PHENOLOGY, NATURAL ENEMIES, AND MANAGEMENT OF LEPIDOPTERAN 
PESTS OF COLE CROPS IN ALABAMA 
 
 
 
 
Except where reference is made to the work of others, the work described in this thesis is 
my own or was done in collaboration with my advisory committee.  This thesis does not 
include proprietary or classified information. 
 
 
 
_____________________________________ 
Elly Marie Maxwell 
 
 
 
 
 
Certificate of Approval: 
 
 
_____________________________   ______________________________ 
Joseph W. Kloepper     Henry Y. Fadamiro, Chair 
Professor      Assistant Professor 
Entomology and Plant Pathology   Entomology and Plant Pathology 
 
 
_____________________________   ______________________________ 
Micky D. Eubanks     Wheeler Foshee  
Associate Professor     Assistant Professor 
Entomology and Plant Pathology   Horticulture 
 
            
             
   ______________________________ 
Stephen L. McFarland 
Acting Dean  
Graduate School 
 
PHENOLOGY, NATURAL ENEMIES, AND MANAGEMENT OF LEPIDOPTERAN 
PESTS OF COLE CROPS IN ALABAMA 
 
 
Elly M. Maxwell 
 
 
 
A Thesis 
Submitted to  
the Graduate Faculty of  
Auburn University  
in Partial Fulfillment of the 
 Requirements for the  
Masters of Science 
 
Auburn, Alabama  
May 11, 2006 
 
 
 iii
PHENOLOGY, NATURAL ENEMIES, AND MANAGEMENT OF LEPIDOPTERAN 
PESTS OF COLE CROPS IN ALABAMA 
 
Elly Marie Maxwell 
 
Permission is granted to Auburn University to make copies of this thesis at its discretion, 
upon request of individuals or institutions and at their expense. The author reserves all 
publication rights 
 
 
 
                                     _________________ 
Signature of Author 
 
May 11, 2006       _____________________ 
Date  
 
       
 
 iv
VITA 
 
 Elly Marie Maxwell was born June 23, 1981 in Midland, Michigan to Casey and 
Roxane Maxwell.  She graduated from Freeland Jr./Sr. High School in 1999 and enrolled 
in Michigan State University (MSU) that fall.  Part of her undergraduate experience 
involved a study abroad program in Costa Rica where she studied environmental science 
at multiple biological stations.  After working three years in the small fruit entomology 
lab with Dr. Rufus Isaacs, she graduated from MSU in 2003 with a B.S. in Entomology.  
She then worked an internship with Rose Exterminator in Saginaw, Michigan.  Elly was 
accepted into the Entomology and Plant Pathology Department as a graduate student in 
August 2003. 
 
 
 
 
 
 
 
 
 v
THESIS ABSTRACT 
PHENOLOGY, NATURAL ENEMIES, AND MANAGEMENT OF LEPIDOPTERAN 
PESTS OF COLE CROPS IN ALABAMA 
 
Elly Marie Maxwell 
M.S., Auburn University, May 11, 2006 
 (B.S., Michigan State University, 2003) 
 
120 Typed Pages 
Directed by Henry Y. Fadamiro 
 
 This thesis first looks at the seasonal abundance of the three key pests of cole 
crops, Plutella xylostella (L.) (Lepidoptera: Plutellidae), diamondback moth; 
Trichoplusia ni (H?bner) (Lepidoptera: Plutellidae), cabbage looper; and Pieris rapae 
(L.), imported cabbageworm in central Alabama on cabbage and collards.  It also does a 
survey of the parasitoid complex of these pests.  The only parasitoid recovered from P. 
xylostella was an ichneumonid wasp, Diadegma insular (Cresson) reaching parasitism 
rates of 57%.  Very sporadic populations of T. ni resulted in very few parasitoids being 
recovered. Lastly, the dominant parasitoid of P. rapae was the pteromalid wasp, 
Pteromalus puparum (L.) which reached parasitism rates of 42.5%.  
  
 vi
The second objective of this thesis is to evaluate two species-specific pheromone-
based experimental attracticide formulations against these pests: Last Call
 TM 
DBM for P. 
xylostella and Last Call
 TM 
CL for T. ni. Laboratory toxicity experiments were first used 
to confirm the effectiveness in killing conspecific males. In replicated small plots of 
cabbage and collards, an attracticide treatment receiving the two Last Call 
TM
 
formulations, each applied multiple times at the rate of 1600 droplets per acre was 
compared against Bacillus thuringiensis subspecies kursatki (Bt) spray at action threshold 
and a negative untreated control. Efficacy was measured by comparing among the three 
treatments the following parameters: male capture in pheromone-baited traps, larval 
counts in plots, and crop damage rating at harvest. The results show that LastCall
TM
 
provided acceptable pest control comparable to Bt in three of the four seasons. Efficacy 
of LastCall
TM
 was shown to be dependent upon lepidopteran population densities, which 
fluctuated from season to season. In general, LastCall
TM
 was effective at low to moderate 
population densities of the three species, such as typically occurs in the fall, but not in the 
spring when high P. rapae population pressure typically occurs in central Alabama. In no 
case did we record significant trap shutdown in LastCall
TM
 plots suggesting that 
elimination of males by the toxicant (permethrin), rather than interruption of sexual 
communication, was probably the main mechanism behind the success of the attracticide 
formulations.  
 The third objective was to evaluate several reduced-risk insecticides for the 
management of these pests. The following formulated sprays were evaluated: Dipel? 
(Bacillus thuringiensis subspecies kursatki), XenTari? (B. thuringiensis subspecies 
aizawai), Dipel+XenTari (a premixed test formulation consisting of both subspecies of B. 
 vii
thuringiensis), Entrust? (a formulation of spinosad), and Novaluron (insect growth 
regulator).  An action threshold of 0.5 cabbage looper equivalents (CLE) per plant was 
used to determine the need for insecticide applications. Insecticide efficacy was 
determined by comparing densities of larvae and immatures (larvae + pupae) of each pest 
species, crop damage ratings, densities of key non-target arthropods, and number of 
insecticide applications in plots treated with each material versus untreated control plots. 
All five reduced-risk insecticide formulations were effective in reducing infestations of 
the three pests and in providing marketable cabbage and collards in Alabama.  No 
significant effects of insecticide treatments were recorded in the numbers of spiders and 
lady beetles found per plant. The results also suggest that the 0.5 CLE action threshold 
can be used to produce marketable cabbage and collards with only minimal applications 
of reduced-risk insecticides. 
 The main goal of this project was to evaluate some componanents of an integrated 
pest management program to control these pests.  Hopefully this information can be used 
to help growers in Alabama build a successful integrated management program for future 
use.
 viii
ACKNOWLEDGMENTS 
I would like to thank my advisor, Dr. Henry Fadamiro for accepting me as his 
graduate student and for his support and patience throughout my years at Auburn.  I want 
to extend another thanks to my committee members: Dr. Micky Eubanks, Dr. Joe 
Kloepper, and Dr. Wheeler Foshee.  I would like to acknowledge Dr. William Moar, Dr. 
Wayne Clark, and Dr. Henry Fadamiro for the teaching experience I gained from 
working with them.  Finally, a special thanks to my parents, Casey and Roxane for their 
support and encouragement throughtout my life. 
 
 
 
 
 
 
 
 
 
 
 ix
Style manual or journal used: Journal of Economic Entomology 
 
Computer software used:  Microsoft Word 2002, Microsoft Excel 2002, SAS for 
Windows version 9.1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 x
TABLE OF CONTENTS 
LIST OF TABLES  ?.???????????????????????. 
LIST OF FIGURES 
CHAPTER I   INTRODUCTION AND RESEARCH OBJECTIVES   
CHAPTER II SEASONAL ABUNDANCE OF THE LEPIDOPTERAN 
 PESTS OF COLE CROPS AND THEIR ASSOCIATED 
PARASITOID GUILD IN ALABAMA ???????.. 
CHAPTER III SUPPRESSION OF PLUTELLA XYLOSTELLA AND 
TRICHOPLUSIA NI IN COLE CROPS BY USING 
PHEROMONE-BASED ATTRACTICIDE  
FORMULATIONS ???????????????.. 
CHAPTER IV EVALUTATION OF SEVERAL REDUCED-RISKED 
INSECTICIDES IN COMBINATION WITH AN ACTION 
THRESHOLD FOR MANAGING LEPIDOPTERAN 
PESTS OF COLE CROPS IN ALABAMA  ?????? 
COMBINED REFERENCES CITED ?????????????????.. 
 
 
 
 
 
xi 
xii 
1 
 
 
13 
 
 
 
30 
 
 
 
70 
93 
 
 
 
 xi
LIST OF TABLES 
Table 3.1.  Percent mortality of male Plutella xylostella and Trichopulsia ni after 
exposure to attracticide (Last Call TM) or double blank formulations. Twenty four  
males were exposed to each formulation. Percent within the same insect column  
having no letters in common are significant at P <.005  
??..?????????.    49 
Table 4.1.  Mean number of applications of each reduced-risk insecticide 
treatment 
 per plot during each season. Treatment applications were made only when 
weekly  
larval counts exceeded a threshold of 0.5 cabbage looper equivalents (CLE) per 
plant???????????????????????????????
.?.  85 
 
 
 
 
 
 
 
 
 
 
 
 
 
 xii
LIST OF FIGURES 
 
CHAPTER TWO 
Figure 1. Seasonal mean (? SE) number adults of lepidopteran species  
sampled. Plutella xylopsella and Trichoplusia ni were sampled using  
pheromone traps checked weekly, whereas Pieris rapae was monitored  
with 5 minute visual counts week during fall 2003 (A) spring 2004 (B), fall 
 2004 (C), and spring 2005 (D) ??..???????????????...    22   
 
Figure 2. Total count of larvae and pupae collected per week of P. rapae  
and associated parasitoids during spring 2004 (A), fall 2004 (B), and  
spring 2005 (C).?????????.???????????????    26 
 
Figure 3. Total count of larvae and pupae collected per week of  
P. xylostella and associated parasitoids during spring 2004 (A), fall 
2004 (B), and spring 2005 (C)  .??????????????????    29  
 
Figure 4. Total count of larvae and pupae collected per week of T. ni  and 
associated parasitoids during spring 2005??????????????..   32
 
 
 xiii
CHAPTER THREE 
Figure 5. Seasonal mean (? SE) number of larvae of the three 
 lepidopteran pest species sampled per plant per week in cabbage subplots  
treated with different treatments during fall 2003 (A) spring 2004 (B), fall  
2004 (C), and spring 2005 (D). DBM = diamondback moth, Plutella  
xylostella; CL = cabbage looper Trichopulsia ni; ICW = imported  
cabbageworm, Pieris rapae. Means followed by the same letter are not 
significantly different (P < 0.05, Tukey-Kramer HSD)  ???...?????    50   
Figure 6. Seasonal mean (? SE) number of larvae of the three lepidopteran 
species sampled per plant per week in collard subplots treated with  
different treatments during fall 2003 (A) spring 2004 (B), fall 2004 (C), 
 and spring 2005 (D). DBM = diamondback moth, Plutella xylostella; CL = 
cabbage looper Trichopulsia ni; ICW = imported cabbageworm, Pieris 
 rapae. Means followed by the same letter are not significantly different 
 (P < 0.05, Tukey-Kramer HSD)  ?????.????????????    54   
 
Figure 7. Mean (? SE) trap capture of diamondback moth (DBM),  
Plutella xylostella  in pheromone baited wing traps for each of three 
 treatments fall 2003 (A) spring 2004 (B), fall 2004 (C), and spring  
2005 (D)???????????????????????..???..     58 
 
 xiv
Figure 8. Mean (? SE) trap capture of cabbage looper (CL), Trichopulsia  
ni in pheromone baited wing traps for each of three treatments during fall 
 2003 (A), fall 2004 (B), and spring 2005 (C) .????????????.    62 
 
Figure 9. Mean (? SE) number of adult imported cabbageworm (ICW),  
Pieris rapae counted during 5-min observation period in untreated and  
treated plots during fall 2003 (A) spring 2004 (B), fall 2004 (C), and  
spring 2005 (D) ?????????????????????...?..?..  65 
 
Figure 10. Mean (? SE) damage ratings of plants harvested from plots of 
 each of three treatments fall 2003 (A) spring 2004 (B), fall 2004 (C), and 
 spring 2005 (D). Line indicates marketability threshold of 3 above which 
 produce is considered unmarketable (Leibee 1995). Means followed by 
 the same letter are not significantly different (P < 0.05, Tukey-Kramer 
HSD)????????????????????????..????    69 
CHAPTER 4 
Figure 11. Caterpillar pressure expressed as mean (? SE) number of  
cabbage looper equivalents (CLE) per plant recorded weekly after  
planting in untreated control plots during spring 2004, fall 2004, and  
spring 2005. Planting dates for spring 2004, fall 2004, and spring 2005  
were March 30 2004, October 2 2004, and April 22 2005, 
respectively?????????????????????????...     86 
 
 xv
Figure 12. Seasonal mean (? SE) number of larvae and immatures of 
lepidopteran species sampled per plant per week in plots treated with 
 different reduced-risk insecticides during spring 2004 (A), fall 2004 (B),  
and spring 2005 (C). Key: CL = cabbage looper (Trichopulsia ni); DBM = 
diamondback moth (Plutella xylostella); ICW = imported cabbageworm  
(Pieris rapae). Means followed by the same letter are not significantly 
 different (P < 0.05, Tukey-Kramer HSD)  ??..???????????     87 
 
Figure 13. Mean (? SE) damage ratings of plants harvested from plots 
 treated with different reduced-risk insecticides during spring 2004 (A),  
fall 2004 (B), and spring 2005 (C). Line indicates marketability threshold  
of 3 above which produce is considered unmarketable. Means followed by  
the same letter are not significantly different (P < 0.05, Tukey-Kramer 
HSD)???????????????????????.?????..   90 
 
 Figure 14. Seasonal mean (? SE) number of non-target spiders and lady 
 beetle adults found per plant per week in plots treated with different 
 reduced-risk insecticides during spring 2004 (A), fall 2004 (B), and spring 
 2005 (C). Means are not significantly different (P > 0.05, Tukey-Kramer 
HSD)????????????????????????????      93 
 1
CHAPTER I: 
 
INTRODUCTION AND RESEARCH OBJECTIVES 
1.1 Cole Crop Production 
Cole crops, Brassica oleracea (L.), including cabbage, collards, broccoli, kale, 
brussels sprouts, and cauliflower, are an important component of diets in many parts of 
the world, including the United States.  Nationally, cabbage is the most common cole 
crop: 80,290 acres of cabbage were planted and 76,850 were harvested in 2003 
translating to a yield of 302 cwt per acre (NASS 2004).  In the year 2002, national 
cabbage production was valued at $301,482,000 (AASS 2003).  
Cabbage and collards are the key cole crops grown in Alabama. Growers in the 
state utilize both spring and fall plantings for both crops, and often grow them in rotation 
with other vegetables (Kemble 1999).  Approximately 1500 acres of cabbage and collards 
are grown in the state of Alabama (Kemble personal communication).  Despite the 
relatively low in the state of Alabama, the high value of the crop (~9,000 US$/ha) and the 
low tolerance of damage accepted for fresh market demands for efficient pest 
management programs to be developed and implemented.
Cabbage and collards are the cole crops grown most commonly in the state of 
Alabama.  Cabbage and collards are grown primarily in the northeastern corner of the 
state in Jackson and DeKalb counties.  The remaining acreage is in Baldwin County and 
the Wiregrass area including Coffee, Dale, Henry, Geneva, and Houston Counties. Cole 
 2
crops are also very common in home gardens, and even on a small scale, the associated 
pests of these crops can be devastating.   
1.2 Non-Lepidopteran Pests 
There is a highly diverse insect pest complex associated with Brassica crops and 
it is represented by several insect orders (Lamb 1989).  Several species of aphids attack 
cole crops in Alabama  (Kemble 1999).  Aphid alates (winged) move onto the plants 
early in the season.  Populations gradually increase through the season peaking prior to 
harvest.  Cabbage aphid (Brevicoryne brassicae), green peach aphid (Myzus persicae) 
and turnip aphid (Lipaphis erysimi) are all fairly common on cabbage in Alabama.  The 
majority of aphids stay on the wrapper leaves and cause minimal damage to the plants.  
turnip mosaic virus is transmitted to the plants by turnip aphid.  Perhaps the most 
destructive problem associated with aphids is contamination.  They can be present in 
large number and are hard to remove before market, and of course, aphid-covered 
cabbage is not favored for fresh market sale (Kemble 1999). 
Cabbage maggot, Delia radicum, is a minor problem in Alabama.  The adults look 
like small black houseflies.  The maggot larvae are small, legless, and are yellow-white in 
color.  Cabbage maggots chew into root hairs creating slimy tunnels on cabbage root 
systems (Bennett et al. 2000). 
 Several species of flea beetles, Phyllotrela spp. are known to feed on cabbage.  
Most commonly are the striped flea beetles, the western black flea beetle, and the crucifer 
flea beetle (Hines and Hutchison 2001b). Adult flea beetles cause the most plant injury.  
The adults overwinter and emerge in mid-spring.  They oviposit on the soil and the larvae 
emerge to feed on the foliage and roots of the plants.  They drop from the plant to pupate 
 3
in the soil (Sorenson 1983).  The beetles are a greater problem for growers in the spring 
months (personal observation) in central Alabama.  The adult beetles chew many small 
irregular shaped holes in the leaves. 
 The Harlequin bug, Murgantia histrionica (Hahn), is another pest frequently 
found in cole crops in Alabama.  It is a brightly colored red and black stinkbug with 
piercing-sucking mouthparts.  It feeds mostly on the veins of leaves causing wilting.  The 
eggs are barrel shaped, black and white, and are laid in clusters (Kemble 1999).  
Harlequin bugs typically reach high populations late in the season in the spring and 
throughout the fall. 
 
1.3 Lepidopteran Pests 
The three key lepidopteran pests of cole crops are: diamondback moth, Plutella 
xylostella L. (Lepidoptera: Plutellidae); imported cabbageworm, Pieris rapae L. 
(Lepidoptera: Pieridae); and cabbage looper, Trichoplusia ni (H?bner) (Lepidoptera: 
Noctuidae).  These pests are often responsible for direct damage to the marketable part of 
the plant and associated frass (Harcourt et al. 1955, Shelton et al.1982, Talekar and 
Shelton 1993, Tabashnik 1994).  The three caterpillars are not equal in the amount of 
damage inflicted on fresh market cabbage (Shelton et al. 1982).  They are however 
similar in their feeding behavior and biology, and commonly are treated as a single 
caterpillar complex (Mahr et al. 1993). 
Their life cycles are similar in that they all oviposit on the foliage of cole crops.  
The eggs hatch into larvae which begin feeding immediately on the surface of the leaves.  
All the larval instars are completed on the plants, and pupation occurs on the underside 
 4
and in the crevices on the leaves.  The adults also occur in close proximity to the plants, 
flying around to mate and lay more eggs again on the plants.  P. xylostella has the 
capacity reaching up to 16 generations per year (Sarnthony et al. 1989). Trichoplusia ni 
and P. rapae also have multiple generations per year in most parts of the world, although 
not nearly as many as P. xylostella. 
The relative abundance of these three caterpillar populations varies depending on 
location and season.  For instance, in the northwestern United States, abundance of P. 
rapae was greatest followed by P. xylostella, and T. ni was least abundant, and frequently 
not observed (Biever et al. 1991).  In the north central part of the country, T. ni is 
reported to be the most damaging to fresh market cabbage (Hines and Hutchinson 2001a).  
In the south central United States, P. xylostella was noted to be the most abundant 
lepidopteran pest (Legaspi et al. 2000).  This shows a varying abundance of these pests in 
different regions of the United States, and underscores the importance of studying their 
relative occurrence in different regions.  Additional minor lepidopteran pests in North 
America include:  beet arymworm, Spodoptera exigua; cabbage webworm, Hellula 
rogatalis, cross striped cabbageworm, Evergestis rimosalis; and cutworms, Agrotis spp. 
Plutella xylostella 
Plutella  xylostella is the most destructive pest of cruciferous plants throughout 
the world and the annual cost for managing P. xylostella is estimated to be $1 billion US 
dollars (Talekar and Shelton 1993).  Although the native land of P. xylostella is debated 
by scientists, it is now accepted as cosmopolitan, damaging crucifers all over the world 
(Wagener 2004).  The fact that it goes through generations quickly and that it has been 
the target of many pesticide sprays has contributed to the development of resistance by 
 5
the pest complex to most conventional insecticides worldwide (Zhao and You 2001).  In 
addition, P. xylostella has been reported to rapidly evolve resistance to Bacillus 
thuringiensis subspecies kurstaki (Bt) in the field (Ferre and van Rie 2002) as well as to 
the spinosyn class (Sayyed 2004).  Resistance to Bt has also been reported in field 
populations of P. xylostella in Hawaii, Malaysia, the Philippines, Japan, Central America, 
Florida, and Thailand (Tabashnik 1994, Telekar and Shelton 1993).    
The sex pheromone of P. xylostella is well documented.  It consists of three 
components: (Z)-11-hexadecanal, (Z)-11-hexadecen-1-o1 acetate, and (Z)-11-
hexadecanol. (Tamaki et al. 1977).  
Trichoplusia ni 
In addition to P. xylostella having resistance issues, T. ni has also been the target 
of a myriad of pesticide sprays.  Therefore, the potential of T. ni to evolve resistance to Bt 
is feared, and was demonstrated among laboratory colonies (Estada and Ferre 1994).  In 
addition, T. ni, has also been reported to evolve resistance to Bacillus thuringiensis 
kurstaki in greenhouse situations in Bristish Columbia (Janmaat and Myers 2003).  . 
Phermonal communication of T. ni is also well understood.  It was first isolated 
by Berger (1965).  (Z)-7-dodecen-1-o1 acetate and (Z)-7-dodecen-1-o1 are the 
components of the sex pheromone (Bjostad et al. 1984).   
Pieris rapae 
Compared to the other pests, P. rapae has shown the least amount of resistance 
development.  It is not usually the target of insecticide sprays, but rather controlled by the 
same pesticides that are sprayed to target T. ni and P. xylostella.  Pheromonal 
 6
communication of P. rapae is not understood, and it is unclear whether they use sex 
pheromones to seek mates. 
 
1.4 Management of Lepidopteran Pests 
1.4.1 Monitoring and Thresholds 
 The most commonly used sampling method for cabbage and its three 
lepidopterous pests is the cabbage looper equivalent (CLE) method (Shelton et al. 1982, 
1983).  The CLE method was proven to be the most accurate and effective method for 
estimating pest populations, although it does take more time than other methods (Shelton 
et al. 1983, Hines and Hutchinson 2001a).  It is used as a basis to determine the threshold 
for insecticide application.  The CLE method accounts for the varying levels of feeding 
damage caused by the three species.  It assigns a relative feeding ratio to each of the three 
pests to standardize the damage potential each individual caterpillar can inflict. In this 
method, 1 CLE = 20 P. xylostella larvae = 1.5 P. rapae larva = 1 T. ni larva (Shelton et 
al. 1982, 1983). For instance, the standard for spraying broccoli is 1.0 CLE (Maltais et al. 
1994) while 0.5 CLE is a commonly used threshold in cabbage and collards (Shelton et 
al., 1982; 1983). 
Plutella xylostella and T. ni synthetic sex pheromone is successful for monitoring 
populations of adult moths in the field (Baker et al. 1982, Shirai and Nakamura 1995, 
Ronald 1997, Reddy and Guerroer 2001, Wang et al. 2004).  Pheromone lures placed in 
wing traps is a successful way to capture adult male moths and therefore monitor 
populations, and will be used in this project. 
 7
At harvest time the method of Greene et al. (1969) was used to evaluate damage 
rating. In this method cabbage plants were rated based on insect feeding damage on a 
scale of 1 to 6 as follows:  1 = no apparent insect damage on head or inner wrapper 
leaves; 2 = no head damage, but minor feeding on wrapper leaves with 0-1% leaf area 
consumed; 3 = no damage on head, but moderate feeding damage on wrapper leaves with 
2-5% leaf area consumed; 4 = minor feeding on head (but no feeding through outer head 
leaves), but moderate feeding on wrapper or outer leaves with 6-10% leaf area consumed; 
5 = moderate to heavy feeding damage on wrapper and head leaves and a moderate 
number of feeding scars on head with 11-30% leaf area consumed; and 6 = severe 
feeding damage to head and wrapper leaves  with heads having numerous feeding scars 
with ? 30% leaf area consumed (Greene et al. 1969). A similar method was used to assess 
marketability of collards in fall 2004 and spring 2005 with damage rating based solely on 
the percent of leaf area consumed (since collards is not a head-producing plant). A 
damage rating of ? 3 is considerable marketable under normal conditions, whereas a 
damage rating of ? 4 is marketable under exceptional market conditions (Leibee et al., 
1995).   
 
1.4.2 Chemical Control 
Traditionally, more attention has been paid to conventional programs than 
biological based control programs for management of the caterpillar complex (Taleker 
and Shelton 1993, Biever et al. 1994, Xu et al. 2004).  Vegetable growers in North 
America have managed the cabbage caterpillar complex in their fields using calendar-
based applications of broad-spectrum insecticides including carbamates (e.g., Sevin and 
 8
Lannate), organophosphates (e.g., Thiodan), and pyrethroids (e.g., Danitol) (Hines and 
Hutchison 2001a, Liu et al. 2002). However, many of these insecticides have now been 
lost due to governmental regulation (Food Quality Protection Act, 1996) or the 
development of pest resistance.  
Because of insecticide resistance concerns with P. xylostella especially, the 
demand for alternatives to conventional pesticide and even Bt is very important.  An 
integrated approach to pest management was introduced nearly half a century ago (Stern 
et al. 1959).  There is a growing understanding that the best way to slow resistance 
development to any one tactic is to combine multiple control methods in this system.  To 
be able to continually depend on the use of Bt sprays depends on the prevention of 
resistance in target pest populations (Ferre and van Rie 2002). 
 
1.4.3 Biocontrol 
The most widely used biologically-based control strategy in cole crops is 
formulated sprays of Bacillus thuringiensis (Bt). Bacillus thuringiensis is now the 
standard insecticide sprayed against the cabbage caterpillar complex in Alabama and 
several other parts of the United States.  As mentioned before, resistance among P. 
xylostella populations to Bt is common, and therefore other tactics to rotate or combine 
with these sprays are necessary. 
 
The natural enemies of the caterpillar complex have been well studied worldwide.   
There is a fairly strong understanding of these beneficial insects, especially the 
parasitoids of the P. xylostella.  There are dozens of different wasp parasitoids of P. 
 9
xylostella from four hymenopteran families (Ichneumonidae, Braconidae, Pteromalidae, 
and Eulopidae), with 7 braconid wasps in the genus Diadegma alone (Wagner et al., 
2004).  Although worldwide Diadegma semiclausum Helen is the most abundant 
parasitoid, (Talekar and Shelton 1993, Shi et al. 2004, Wagener 2004), Diadegma 
insulare (Cresson) is the most important and abundant parasitoid of P. xylostella in the 
United States (Lasota and Kok 1986, Biever et al. 1991, Mitchell et al. 1997, Godin and 
Boivin 1998, Legaspi et al. 2000, Xu et al 2004, Shi et al. 2004).  Diadegma  insulare 
accounted for 98% of the parasitoids reared from field collected P. xylostella larvae in the 
state of Texas, although alone it did not provide sufficient control of the caterpillar pest 
(Legaspi et al, 2000).  It was the only parasitoid we recovered s from populations of P. 
xylostella in Alabama (Fadamiro and Maxwell, unpublished data).  However, Harvey and 
Eubanks (2003) recovered Cotesia plutellae Kurdjumov (Hymenoptera: Brachonidae) 
from P. xylostella in nearby field sites.  The success and importance of Diadegma spp. 
was illustrated when D. semiclausum out-competed C. plutellae when the two were 
compared, supporting the idea that it is a successful and steadfast control for P. xylostella  
(Shi et al. 2004).  Therefore, the demand to conserve these parasitoids is very important 
in a successful integrated program. 
Unfortunately, most of the synthetic insecticides commonly used in Brassica 
fields are detrimental to D. insulare (Xu et al. 2004) and other parasitoids.  Therefore, the 
incorporation of compatible chemical control methods is crucial.  It is imperative that 
research in the area of reduced risk insecticides (including bacteria-derived insecticides 
and insect growth regulators) continue; both for the conservation of the natural enemy 
guild and for protection of the environment and human health. 
 10
Parasitic wasps have been extensively studied for their contribution to control of 
the caterpillar complex; however, little understanding of the role of predators such as 
carabid beetles and spiders is known (Talekar and Shelton 1993).  In Australia, carabids, 
lady beetles, rove beetles, green lacewings, and spiders, are known to play a role in 
predation of the lepidopteran pests of cole crops (Furlong et al. 2004).  Carabids do 
contribute to larval mortality of both P. xylostella and P. rapae (Schellhorn and Sork 
1997, Suenaga and Hamamura 2001).  Field boundaries are important in that they serve 
as reservoirs of beneficial carabid beetles (Wratten et al. 1998).  Certain species of 
carabid beetle larvae have been shown to climb plants to forage and also consume the 
larvae of P. xylostella in Japan (Suenaga and Hamamura 1998).  Predator activity is 
known to increase as shelter areas (i.e. weed growth, ground cover, etc.) in and around 
cole crop fields are available (Cranshaw 1984), implying that it may be beneficial to 
leave refuge areas to maximize natural enemy control. However, there is no evidence that 
interplanting necteriferous plants among cabbage increases parasitoid abundance in 
cabbage fields (Al-Doghairi and Cranshaw 2004). 
Population dynamics of the cruciferous caterpillar complex and associated natural 
enemies have been studied in various regions of North America (Pimental, 1961; 
Harcourt et al. 1963; Oatman and Platner 1969, Elsey and Rabb 1970, Biever 1972, 
Harding 1976, Ru and Workman 1979, Andalaro et al. 1982, Latheef and Irwin 1983, 
Chamberlin and Kok 1986, Kok and McAvoy 1989, Biever et al. 1991).  However, 
information on abundance and occurrence of these three pests and their associated 
parasitoids in the state of Alabama is limited.   
 
 11
 
 
1.4.4 Semiochemical-Based Control  
 Pheromones are utilized in pest control in multiple ways.  Mass trapping and 
mating disruption are the most common applications for pheromone-based control.  
Mating disruption is accomplished by releasing large amount of pheromone from many 
point sources (Gaston et al. 1967, Farka et al., 1974).   
 Attracticide technology which incorporates an attractant (sex pheromone, floral, 
food) with a toxicant has been evaluated again multiple pests.  Attracticide tactics were 
shown by Losel et al. (2000) and Charmillot et al. (1997, 2000) to be successful in 
controlling codling moth, Cydia pomonella in European apple orchards.  It also was 
shown to successfully control the pink bollworm, Pectinophora gossypiella (Hofer and 
Angst 1995) and the light brown apple moth (Suckling and Brockerhoff 1999).   
 The LastCall
TM
 formulations used in the laboratory and field experiments were 
formulated and supplied by IPM Tech Inc., Portland, OR (now known as IPM 
Development Company, Marylhurst) and consisted (in addition to pheromone and 
toxicant) of a clear viscous paste (gel) with a base proprietary product plus other inert 
ingredients. Two species-specific experimental formulations were evaluated: i) Last Call
 
TM 
DBM for P. xylostella consisting of 0.16% pheromone and 6% permethrin by weight), 
and ii) Last Call
 TM 
CL for T. ni consisting of 1.6% pheromone and 6% permethrin by 
weight. The sex pheromone of P. xylostella consists of three components: (Z)-11-
hexadecanal, (Z)-11-hexadecen-1-ol acetate, and (Z)-11-hexadecanol (Tamaki et al. 
1977), while (Z)-7-dodecen-1-ol acetate and (Z)-7-dodecen-1-ol are the components of T. 
 12
ni sex pheromone (Berger 1966, Bjostad et al. 1984). The sex pheromone of each species 
was purchased from Bedoukian Research Inc. (Danbury, CT) and used as attractant in the 
proprietary formulations (IPM Tech Inc., Portland, OR). The Last Call
 TM
 formulations 
were dispensed from an applicator tube with a calibrated pump that deposits metered 
droplets. Each 50 ?l droplet of the gel formulation weighed ~ 50 mg and consisted of 
pheromone and permethrin as active ingredients.   
The advantage to baiting the droplets with a sex pheromone makes the 
formulations species specific.  An additional advantage that might favor the attractiveness 
of attracticide-baited traps might be the fact that droplets emit pheromones before the 
females are present or begin calling (Krupke et al., 2002).  Also, with males contacting 
droplets, Haynes et at. (1986) showed that even sub-lethal insecticide doses to the pink 
bollworm, Pectinophora gossypiella impaired the ability of male moths to locate sources 
of pheromone. 
 
1.5 Research Objectives 
a. Determine seasonal abundance and phenology of cabbage caterpillar pest 
complex and associated natural enemies in central Alabama. 
b. Evaluate the efficacy of attracticide for suppression of Plutella xylostella and 
Trichoplusia ni in cole crops using pheromone-based attracticide formulations in 
comparision to a grower standard (Bt spray) and a negative control. 
c.  Field evaluation of reduced risk insecticides against cabbage-caterpillar complex 
in Alabama. 
 
 13
CHAPTER II : 
SEASONAL OCCURRENCE OF THE LEPIDOPTERAN PESTS OF COLE 
CROPS AND ASSOCIATED PARASITOIDS IN ALABAMA 
 
2.1 Introduction 
 
Diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), imported 
cabbageworm Pieris rapae (L.) (Lepidoptera: Pieridae) and cabbage looper, Trichoplusia 
ni (Hubner) (Lepidoptera: Noctuidae) are the three key lepidopterous pests of cole crops 
worldwide.  They have similar feeding habits and host ranges do similar damage to the 
foliage of cole crops, and are therefore treated as a single caterpillar complex (Mahr et al. 
1993).  They are responsible for damage directly to the marketable part of the plant 
(Harcourt et al. 1955; Shelton et al. 1982 Talekar and Shelton 1993; Tabashnik 1994).   
Despite the relatively few numbers of acres of cabbage and collards grown in the 
state of Alabama, the high value of the crop (~9,000 US$/ha) demands for efficient pest 
management programs to be developed and implemented.  Broad-spectrum insecticides, 
such as organophosphates, pyrethroids, and carbamates have been used traditionally for 
control of these pests (Hines and Hutchison 2001, Liu et al. 2002).  Unfortunately, 
resistant populations, non-target effects, and government regulations (Food Quality 
Protection Act, 1996) have directed most growers in the state of Alabama to rely on 
Bacillus thuringiensis sprays as a standard for control of these pests (Kemble personal 
communication).  Bacillus thuringiensis is a good method for control because it is
14  
specific to lepidopteran insects, targeting only insects in that order and thus preserving 
the natural enemy complex.  The pests and their natural enemies have been studied 
throughout the U.S. In the northwestern United States, abundance of P. rapae was 
greatest followed by P. xylostealla, and T. ni was least abundant, and frequently not even 
observed (Biever et al., 1991).  In the midwest part of the country (Minnesota) T. ni is 
reported to be the most damaging to market cabbage (Hines and Hutchinson 2001).  In 
the south central United States, P. xylostella was noted to be the most abundant 
lepidopteran pest (Legaspi et al., 2000).  This shows a varying abundance of the pests 
having regional difference throughout the United States, and indicated the importance of 
studying the relative occurrence in different areas independently.   
The natural enemies of the caterpillar complex have been well studied worldwide.   
There is a fairly strong understanding of these beneficial insects, especially the 
parasitoids of P. xylostella.  There are dozens of different wasp parasitoids of P. 
xylostella from four hymenopteran families (Ichneumonidae, Braconidae, Pteromalidae, 
and Eulopidae), with 7 braconid wasps in the genus Diadegma alone (Wagner et al. 
2004).  Although worldwide Diadegma semiclausum Hellen is the most abundant 
parasitoid, (Talekar and Shelton 1993, Shi et al. 2004, Wagener, 2004), Diadegma 
insulare (Cresson) is the most important and abundant parasitoid of P. xylostella in the 
United States (Mahr et al. 1993, Lasota and Kok 1986, Biever et al. 1991, Mitchell et al. 
1997, Godin and Boivin 1998, Legaspi et al. 2000, Xu et al 2004 Shi et al. 2004).  D. 
insulare accounted for 98% of the parasitoids reared from field collected P. xylostella 
larvae in the state of Texas, although alone it did not provide sufficient control of the 
caterpillar pest (Legaspi et al, 2000). 
15  
Population dynamics of these three caterpillar pest species have been studied in 
various regions of North America (Pimental 1961, Harcourt 1963, Oatman and Platner 
1969, Elsey and Rabb 1970, Biever 1972, Harding 1976, Ru and Workman 1979, 
Andalaro et al. 1982, Latheef and Irwin 1983, Chamberlin and Kok 1986, Kok and 
McAvoy 1989, Biever et al. 1991).  However, information on abundance and occurrence 
of these three pests and their associated parasitoids in the state of Alabama is limited.   
In this experiment, we intend to determine the seasonal abundance of the pest 
complex and its associated parasitoid guild.  With the knowledge of pest composition and 
the natural enemy complex, growers in the state will be better able to utilize the 
biocontrol agents as part of an integrated pest management system.  This study will be the 
first to describe seasonal parasitism of Lepidoptera in cabbage grown under commercial 
conditions in this production area. 
2.2 Materials and Methods 
 2.2.1 General Methods 
All data was collected at the E.V. Smith Agricultural Research Station in central 
Alabama.  Eggs, larvae, and pupae of the three species were transported to the lab in a 
Styrofoam container via an air conditioned car and reared individually on freshly picked 
and washed collard leaves in Petri dishes in laboratory conditions.  Emergence of the 
adults as well as parasitoids was recorded in the laboratory.   
 
2.2.2 Preliminary Season 
The year 2003 was used as a preliminary season where the objectives were to 
evaluate the type, activity, and abundance of parasitoids of the cabbage caterpillar 
16  
complex. Eggs, larvae and pupae of the three pests were randomly collected and reared in 
laboratory conditions in individual Petri dishes on cabbage leaves. ?Vates? collards and 
?Bravo? cabbage were grown. 
 
2.2.3 Pest Phenology Experiment 
The three lepidopteran pests were monitored at the E.V. Smith Agricultural 
Research Station.  Populations of adult males of P. xylostella and T. ni were monitored 
weekly by placing in the center of each plot two wing traps baited with the commercial 
pheromone lures one for each species (IPM Tech Inc., Portland, OR). The two traps were 
spaced apart by ~ 10 m. Since no pheromone-baited traps are currently available for 
monitoring P. rapae, adult population of this species was monitored weekly using a 
visual method. This was done weekly by an observer (E. Maxwell) standing in the center 
of each plot and counting the number of adult P. rapae seen in the plot during a 5-minute 
observation period. 
In spring 2004, ?Vates? collards were grown.  In fall 2005, ?Rio Verde? cabbage 
and ?Top bunch? collards were grown.  In spring 2005 ?Bravo? cabbage and ?Vates? 
collards were grown. 
Each season, 50 plants were sampled randomly weekly in each plot.  Eggs, larvae, 
and pupae of the three species were transported to the laboratory in a Styrofoam container 
via an air conditioned car and reared individually on freshly picked and washed collard 
leaves in Petri dishes in laboratory conditions.   
Emergence of the adults as well as parasitoids was recorded in the laboratory.   
In the case of excessive P. rapae egg densities, only one was removed from each plant. 
17  
 
2.3 Results and Discussion 
 Populations of all three species varied by season.  In general, adult, larvae and 
pupal populations of all species were greater in the spring seasons than in the fall.  
Plutella xylostella showed to be the most consistent and abundant pest (Fig. 1) across all 
seasons.  Pieris rapae was present in all growing seasons, but was very abundant in 
spring 2004 (Fig. 1, Fig. 2).  Populations of T. ni were sporadic across the three seasons, 
and were the highest in the spring 2005 (Fig 1, Fig 4).  Trichoplusia ni populations were 
not present in spring 2004, and were only found in the adult stage in Spring Fall 2004 at 
small numbers (Fig. 1).   
Pieris rapae had the most diverse parasitoid complex.  Three species of 
parasitoids were recovered including Pteromalus puparum, Phyrxe vulgaris (Fallen), and 
Brachymeria ovata.  The most common was Pteromalus puparum, which in the 
preliminary season late in the summer was collected at rates as high as 86%.  In fall of 
2004 parasitism rates were also high, at 41.0% overall and reaching a maximum of 57% 
the week of December 2 .  Rates of parasitism of P. rapae increased as the season 
progressed (Fig. 3), and were far more abundant in the fall seasons than the spring 
seasons.  
 The only parasitoid recovered from P. xylostella was Diadegma insulare, but it 
was recovered in very high percentages, especially later in the season.  It was common in 
both the fall and the spring seasons reaching up to 77% parasitism midseason spring 
2005. 
18  
 Throughout much of our study, T. ni was not very abundant.  With the exception 
of fall 2003 and spring 2005, significant levels at the station were not recorded.  In spring 
2005 the populations of this pest were high, but still parasitism rates were very low 
suggesting perhaps the inexistence of the pest in previous seasons reduced the parasitoid 
populations.  The only parasitoids recovered from larvae and pupae of T. ni was Voria 
ruralis and Litomastix truncatellum, both at very low rates.  A single Trichogramma spp 
wasp was recovered in the prelimilary season. a very high number of individuals in each 
parasitized pupa. 
 In many cases, the level of parasitoid activity we observed would not provide 
sufficient protection of cruciferous crops from the pest complex.  To increase the 
effectiveness of the parasitoids it is very important that a grower continue to use reduced-
risk insecticides that do not have nontarget effects. Judicious use of Bacillus thuringiensis 
or other bacterial derived insecticides have no effect on these parasitoids.  Additionally, 
seasonal inoculations of some of these species might increase populations that are 
currently very small.  The data generated in this study serves as a baseline study, the first 
data of its sort collected in Alabama, to assist in the development of a biological control 
management strategy that takes advantage of the parsitoid complex for control of the 
lepidopterous pests of cole crops.   
 
19  
Fall 2003
0
5
10
15
20
25
10/6 10/13 10/20 10/27 11/3 11/10 11/17
2003
Me
a
n
 (? 
S
E
)
 
a
d
u
l
ts
 p
e
r
 tr
a
p
 
o
P. xylostella
T. ni
P. rapae
 
Figure 1a. Seasonal mean (? SE) number adults of lepidopteran species sampled. 
Plutella xylopsella and Trichoplusia ni were sampled using pheromone traps checked 
weekly, whereas Pieris rapae was monitored with 5 minute visual counts week during 
fall 2003 (A). 
 
 
 
 
 
 
 
 
 
20  
Spring 2004
0
10
20
30
40
50
60
4/10 4/17 4/24 5/1 5/8 5/15 5/22 5/29 6/5
2004
M
e
a
n
 (?
 SE
) 
a
d
u
l
ts
 pe
r
 
tr
a
p
 
o
P. xylos tella
T. ni
P. rapae
 
Figure 1b. Seasonal mean (? SE) number adults of lepidopteran species sampled. 
Plutella xylopsella and Trichoplusia ni were sampled using pheromone traps checked 
weekly, whereas Pieris rapae was monitored with 5 minute visual counts week during 
spring 2004. 
 
 
 
 
 
 
 
 
21  
 Fall 2004
0
2
4
6
8
10
12
14
16
10/11 10/18 10/25 11/1 11/8 11/15 11/22 11/29 12/6
2004
Me
a
n
 (? S
E
) a
d
u
l
s
 
p
e
r
 
tr
a
p
 o
r
P. xylostella
T. ni
P. rapae
 
Figure 1c. Seasonal mean (? SE) number adults of lepidopteran species sampled. 
Plutella xylopsella and Trichoplusia ni were sampled using pheromone traps checked 
weekly, whereas Pieris rapae was monitored with 5 minute visual counts week during 
fall 2004. 
 
 
 
 
 
 
 
 
 
22  
 Spring 2005
0
5
10
15
20
25
30
35
40
5/3 5/10 5/17 5/24 5/31 6/7 6/14 6/21 6/28
2004
M
e
a
n
 (
?
 SE
)
 
a
dul
t
s
 pe
r
 t
r
a
p
 o
P. xylostella
T.ni
P. rapae
 
Figure 1.d. Seasonal mean (? SE) number adults of lepidopteran species sampled. 
Plutella xylopsella and Trichoplusia ni were sampled using pheromone traps checked 
weekly, whereas Pieris rapae was monitored with 5 minute visual counts week during 
spring 2005. 
 
 
 
 
 
23  
Spring 2004 P. rapae
0
25
50
75
100
125
150
175
4/16 4/23 4/30 5/7 5/14 5/21 5/28 6/4 6/11 6/18
l
a
rva
e
 +
 p
u
p
ae 
col
l
e
B. ovata
P. puparium
P. pecosensis
P. rapae
 
Figure 2.a. Total count of larvae and pupae collected per week of P. rapae and 
associated parasitoids during spring 2004. 
 
 
 
 
 
 
 
 
24  
Fall 2004 P. rapae
0
5
10
15
20
25
10/11 10/18 10/25 11/1 11/8 11/15 11/22 11/29 12/6
l
a
rva
e
 +
 p
u
p
ae 
col
l
e
B. ovata
P. puparium
P. pecosensis
P. rapae
 
Figure 2.b. Total count of larvae and pupae collected per week of P. rapae and 
associated parasitoids during fall 2004. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
25  
 
 
 
 
 
 
 
 
Figure 2.c. Total count of larvae and pupae collected per week of P. rapae and 
associated parasitoids during spring 2005. 
 
 
 
 
 
 
 
 
 
Spring 2005 P. rapae
0
25
50
75
100
4/25 5/2 5/9 5/16 5/23 5/30 6/6 6/13 6/20 6/27
l
a
r
v
a
e
 +
 pupa
e
 c
o
l
l
e
c
B.ovata
P. puparium
P. pecosensis
P. rapae
26  
Spring 2004 P. xylostella
0
5
10
15
20
25
30
35
4/16 4/23 4/30 5/7 5/14 5/21 5/28 6/4 6/11 6/18
l
a
rv
a
e
 +
 p
u
p
a
e 
co
l
l
e
D. ins ulare
P. xylostella
 
Figure 3.a. Total count of larvae and pupae collected per week of P. xylostella and 
associated parasitoids during spring 2004. 
 
 
 
 
 
 
 
 
27  
Fall 2004 P. xylostella
0
5
10
15
20
25
30
35
40
45
50
10/11 10/18 10/25 11/1 11/8 11/15 11/22 11/29 12/6
l
a
rv
a
e
 +
 p
u
p
a
e
 co
l
l
e
D. insulare
P. xylostella
 
Figure 3.b. Total count of larvae and pupae collected per week of P. xylostella and 
associated parasitoids during fall 2004. 
 
 
 
 
 
 
 
 
28  
Spring 2005 P. xylostella
0
10
20
30
40
50
60
70
4/25 5/2 5/9 5/16 5/23 5/30 6/6 6/13 6/20 6/27
l
a
rv
a
e
 +
 p
u
p
a
e
 co
l
l
e
D. insulare
P. xylostella
 
Figure 3.c. Total count of larvae and pupae collected per week of P. xylostella and 
associated parasitoids during spring 2005. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
29  
 
 
 
 
 
 
 
Figure 4. Total count of larvae and pupae collected per week of T. ni  and associated 
parasitoids during spring 2005.
 
 
 
 
Spring 2005 T. ni
0
10
20
30
40
50
4/25 5/2 5/9 5/16 5/23 5/30 6/6 6/13 6/20 6/27
l
a
rv
ae +
 
p
u
p
a
e co
l
l
e
c
L.truncatellum
V. ruralis
T. ni
 30
CHAPTER III : 
SUPPRESSION OF PLUTELLA XYLOSTELLA AND TRICHOPLUSIA NI IN 
COLE CROPS BY USING PHEROMONE-BASED ATTRACTICIDE 
FORMULATIONS 
3.1 Introduction 
The diamondback moth (DBM), Plutella xylostella L. (Lepidoptera: Plutellidae), 
cabbage looper (CL), Trichoplusia ni (H?bner) (Lepidoptera: Noctuidae), and imported 
cabbageworm (ICW), Pieris rapae L. (Lepidoptera: Pieridae) are the key pests of 
cruciferous plants (Brassica spp.) in North America.  Lepidopteran larvae feed on the 
foliage and cause direct damage to the marketable part of cole crops (Harcourt et al. 
1955, Shelton et al. 1982, Talekar and Shelton 1993, Tabashnik 1994). The three species 
are usually managed together as a single caterpillar complex, commonly referred to as the 
cabbage caterpillar complex (Shelton et al. 1982, Mahr et al. 1993, Hines and Hutchison 
2001).  
Traditionally, vegetable growers in North America have managed the cabbage 
caterpillar complex in their fields using calendar-based applications of broad-spectrum 
insecticides including carbamates (e.g., Sevin and Lannate), organophosphates (e.g., 
Thiodan), and pyrethroids (e.g., Danitol) (Hines and Hutchison 2001, Liu et al. 2002). 
However, many of these insecticides have now been lost due to governmental regulation 
(Food Quality Protection Act, 1996) or the development of pest resistance. The most 
 31
widely used biologically-based control strategy in cole crops is formulated sprays 
of Bacillus thuringiensis (Bt). Bacillus thuringiensis is now the standard insecticide 
sprayed against the cabbage caterpillar complex in Alabama and several other parts of the 
United States. However, Bt-resistant field populations of P. xylostella have been reported 
in various locations world-wide (Mahr et al. 1993, Rueda and Shelton 1995, Tabashnik et 
al. 1997). Furthermore, Bt sprays are directed against pest larvae and thus allow some 
level of feeding damage to take place before mortality occurs. These concerns have 
prompted renewed interests in the development of alternative pest management tactics 
against the cabbage caterpillar complex. Integrating Bt sprays with another biologically 
based tactic (such as the use of semiochemicals) may have the potential of reducing the 
risk of resistance to Bt, and increase its efficacy.    
Semiochemical-based strategies, including mating disruption and attracticides 
(attract-and-kill or lure and kill) can potentially be used to manage two of the three key 
lepidopteran pests of cole crops: P. xylostella and T. ni. The sex pheromone of both 
species have been characterized (Berger 1996, Tamaki et al. 1977, Bjostad et al. 1984), 
and studies have demonstrated the efficacy of mating disruption of P. xylostella and T. ni 
(Gaston et al. 1967, Farka et al. 1974, Mitchell et al. 1997, Mitchell 2002). Recently, 
there has been some focused interest in the potential use of semiochemicals as 
attracticides for pest management. The attracticide technology incorporates an attractant 
(e.g., synthetic pheromones) with an insecticide (e.g., permethrin), and its utility is based 
on the attraction of individuals of the target species to a hydrophobic matrix containing 
an insecticide where they are killed without insecticide run-off or drift, thereby limiting 
contamination of the crop and the ecosystem. The tactic is considered useful and 
 32
promising because, unlike mass trapping, traps do not have to be deployed and serviced, 
and unlike mating disruption, males are actually killed, rather than confused. This 
technology has shown significant promise for the control of several key lepidopteran pest 
species including Pectinophora gossypiella (Saunders) (Haynes et al. 1986, Hofer and 
Angst 1995), Epiphyas postvittana (Walker) (Brockerhoff and Suckling 1999), Cydia 
pomonella (L.) (Charmillot and Hover 1997, Charmillot et al. 2000, Losel et al. 2000, 
Krupke et al. 2002, Evenden and McLaughlin 2005), and Grapholita molesta (Busck) 
(Evenden and McLaughlin 2004a,b, 2005). Mitchell (2002) reported the initial 
development of attracticide formulations against P. xylostella and T. ni, while Mullan 
(2003) evaluated some experimental attracticide formulations against T. ni in commercial 
vegetable greenhouses. The results of both studies demonstrated the potential of the 
attracticide technology for managing both pests in cole crops (Mitchell 2002, Mullan 
2003).   
 In this paper, we report on laboratory and field experiments conducted to further 
evaluate the potential of attracticide formulations for managing P. xylostella and T. ni on 
cole crops. We tested two species-specific pheromone-based commercial attracticide 
formulations (one for P. xylostella and one for T. ni) supplied by IPM Tech Inc., 
Portland, OR (now known as IPM Development Company, Marylhurst, OR), which holds 
the global license rights to an attracticide matrix gel (LastCall
TM
). Laboratory 
experiments were conducted to determine the toxicity of LastCall
TM
 formulations to 
laboratory-reared P. xylostella and T. ni males. We then evaluated over multiple field 
seasons the efficacy of LastCall
TM
 formulations for suppression of lepidopteran pest 
infestation and damage in crucifer plots, in comparison to Bt and a negative untreated 
 33
control. Ultimately, we were interested in determining whether or not the attracticide 
technology could provide acceptable control of the cabbage caterpillar complex and yield 
marketable crops comparable to Bt despite the fact that LastCall
TM
 formulations are not 
currently available against P. rapae, a key member of the cabbage caterpillar complex in 
Alabama. 
   
3.2 Materials and Methods 
3.2.1 Attracticide formulations 
The LastCall
TM
 formulations used in the laboratory and field experiments were 
formulated and supplied by IPM Tech Inc., Portland, OR (now known as IPM 
Development Company, Marylhurst) and consisted (in addition to pheromone and 
toxicant) of a clear viscous paste (gel) with a base proprietary product plus other inert 
ingredients. Two species-specific experimental formulations were evaluated: i) Last Call
 
TM 
DBM for P. xylostella consisting of 0.16% pheromone and 6% permethrin by weight), 
and ii) Last Call
 TM 
CL for T. ni consisting of 1.6% pheromone and 6% permethrin by 
weight. The sex pheromone of P. xylostella consists of three components: (Z)-11-
hexadecanal, (Z)-11-hexadecen-1-ol acetate, and (Z)-11-hexadecanol (Tamaki et al. 
1977), while (Z)-7-dodecen-1-ol acetate and (Z)-7-dodecen-1-ol are the components of T. 
ni sex pheromone (Berger 1966, Bjostad et al. 1984). The sex pheromone of each species 
was purchased from Bedoukian Research Inc. (Danbury, CT) and used as attractant in the 
proprietary formulations (IPM Tech Inc., Portland, OR). The Last Call
 TM
 formulations 
were dispensed from an applicator tube with a calibrated pump that deposits metered 
droplets. Each 50 ?l droplet of the gel formulation weighed ~ 50 mg and consisted of 
 34
pheromone and permethrin as active ingredients. Formulations were kept in a -20? C 
freezer until use. 
 
3.2.2 Laboratory experiments 
 We conducted simple ?touch? toxicity tests to determine the toxicity of both 
experimental attracticide formulations by comparing exposure of adult P. xylostella and 
T. ni to conspecific Last Call
 TM
 formulations versus a double blank formulation (with no 
insecticide or pheromone). Both lepidopteran species were reared in the laboratory on 
modified pinto bean diet using standard rearing protocols for each species (McEwen and 
Hervey 1960, Guy et al. 1985, Shelton and Collins 2002). Pupae of each species were 
harvested from diet, sexed, and held individually in 1 oz plastic cups until adult 
emergence. Prior to the tests, moths were chilled briefly in the refrigerator (at 5 ? C for 
~15 min) to reduce activity. For each species, 24 newly-emerged (1 day old) males were 
treated with their conspecific Last Call
 TM
 formulation by using a toothpick to apply 
(touch) 1 drop of the gel to the back of the thorax. Treated moths were placed 
individually in 1 oz plastic cups (with lid) and provided with a 25% sugar solution (using 
cotton dental wicks). The cups were arranged in a random order on a tray and placed in a 
fume cupboard maintained at ~ 25? C and a photoperiod of 14:10 (L:D). The control 
treatment for each species consisted of another set of males exposed to a double blank 
formulation (no permethrin, no pheromone). Effect of contact with Last Call
 TM
 was 
determined by checking for male mortality at 2 and 24 h after exposure, scoring 
individual male as alive (apparently fully functional) or dead. Significant differences in 
the toxicity of Last Call
 TM
 and double blank formulations to males of each species were 
 35
established using a ?
2
 2 ? 2 test of independence with Yates? correction for continuity 
(Parker 1979). 
 
3.2.3 Field evaluation of attracticide formulations 
We conducted field experiments in replicated small plots of cabbage and collards 
to evaluate the efficacy of LastCall
TM
 formulations in controlling P. xylostella and T. ni 
infestations. This study was conducted over four growing seasons (fall 2003, spring 2004, 
fall 2004, and spring 2005) at the E.V. Smith Agricultural Research Station in Shorter, 
central Alabama.  Plots were 27.4 m by 18.2 m with plants spaced 45 cm apart within a 
row and 90 cm between rows for a total of 600 plants per plot.  Plots were separated by 
33.5 m and each plot was then subdivided into two equal subplots consisting of 300 
cabbage plants and 300 collard plants. Plots were initially bare ground and established by 
transplanting cabbage (Brassica oleraceae L. var. capitata L.) and collard (Brassica 
oleraceae L. var. acephala L.) seedlings obtained from a nursery in western Georgia 
(Lewis Taylor Farms, Ty Ty, Georgia) following a preseason fire ant (Solenopis invicta 
Buren) treatment with Amdro? (active ingredient = hydramethylnon, BASF Corporation, 
Research Triangle Park, NC). In fall of 2003 ?Bravo? cabbage and ?Vates? collards were 
mechanically transplanted on 24 September 2003.  In spring of 2004 ?Bravo? cabbage and 
?Vates? collards were mechanically transplanted on 2 April 2004.  In fall 2004, ?Rio 
Verde? cabbage and ?Top bunch? collards were mechanically transplanted on 3 October 
2004.  In spring 2005, ?Bravo? cabbage and ?Vates? collards were mechanically 
transplanted on 22 April 2005.  Standard field preparation and crop production practices 
(i.e., irrigation, herbicide, fertilizer) were used to establish and maintain cabbage and 
 36
collard plants in all four growing seasons. In each season, three treatments were 
evaluated: i) Attracticide treatment involving applications of P. xylostella and T. ni 
LastCall
TM
 formulations; ii) Bt spray at action threshold, and iii) Untreated control. 
Treatments were arranged in a randomized complete block design with three replicates 
(blocks) in each season (the experiment was replicated in three blocks with each block 
containing three plots, one for each treatment). Blocks were separated by ~ 60 m. In each 
season, each attracticide plot received multiple applications of the two formulations: 
LastCall
TM 
DBM and LastCall
TM 
CL. One droplet (50 mg) of each LastCall
TM
 
formulation was applied to an unmarketable outer leaf of 100 plants per plot (50 plants 
per subplot), translating to a low rate of about 1600 droplets per acre. This application 
rate translated to ~ 0.14 g and 1.4 g of pheromone/acre for P. xylostella and T. ni, 
respectively, and was shown to be effective in preliminary experiments (Mitchell 2002, J. 
McLaughlin, unpublished data). The treated plants were evenly distributed in the plot. 
LastCall
TM
 applications were made at 2 week intervals during the first month of each 
growing season to accommodate early season leaf drop, and at 3-4 week intervals 
thereafter, for a total of 3-4 applications per season.  
Plots were evaluated weekly for pest infestation by sampling ten randomly 
selected plants per plot, 5 from each subplot, for larvae of P. xylostella, T. ni, and P. 
rapae. The species, numbers, and size (instar) of caterpillars per plant were counted and 
recorded. Eggs and pupae of the three species were also sampled, but only larval data are 
presented in this paper. For the Bt treatment, Dipel? (a formulation of B. thuringiensis 
subspecies kurstaki) was applied, since it is currently the most commonly used microbial 
insecticide on Alabama vegetable crops (Kemble, personal comm.) 
 37
Applications of Dipel? (Valent Biosciences Libertyville, IL) were made only 
when larval counts exceeded a threshold of 0.5 cabbage looper equivalents (CLE) per 
plant (Shelton et al. 1982, 1983). The CLE method accounts for the varying levels of 
feeding damage caused by the three species. In this method, 1 CLE = 20 P. xylostella 
larvae = 1.5 P. rapae larva = 1 T. ni larva (Shelton et al. 1982 1983). Dipel? applications 
were made at the recommended rate of 1 pound per acre with a CO
2
 pressurized 
backpack sprayer using a 3-ft boom with 3 nozzles calibrated to deliver about 25 gpa at 
40 psi. On average, each Bt plot received 2-3 applications of Dipel? per season. 
Populations of adult males of P. xylostella and T. ni were monitored weekly by placing in 
the center of each plot two wing traps baited with the commercial pheromone lures one 
for each species (IPM Tech Inc., Portland, OR). The two traps were spaced apart by ~ 10 
m. Since no pheromone-baited traps are currently available for monitoring P. rapae, adult 
population of this species was monitored weekly using a visual scheme. This was done 
weekly by an observer (E. Maxwell) standing in the center of each plot and counting the 
number of adult P. rapae seen in the plot during a 5-minute observation period. 
 At harvest, ten plants were randomly selected from each subplot and rated for 
caterpillar feeding damage and marketability using the method of Greene et al. (1969). In 
this method cabbage plants were rated based on insect feeding damage on a scale of 1 to 
6 as follows:  1 = no apparent insect damage on head or inner wrapper leaves; 2 = no 
head damage, but minor feeding on wrapper leaves with 0-1% leaf area consumed; 3 = no 
damage on head, but moderate feeding damage on wrapper leaves with 2-5% leaf area 
consumed; 4 = minor feeding on head (but no feeding through outer head leaves), but 
moderate feeding on wrapper or outer leaves with 6-10% leaf area consumed; 5 = 
 38
moderate to heavy feeding damage on wrapper and head leaves and a moderate number 
of feeding scars on head with 11-30% leaf area consumed; and 6 = severe feeding 
damage to head and wrapper leaves  with heads having numerous feeding scars with ? 
30% leaf area consumed (Greene et al. 1969). A similar method was used to assess 
marketability of collards with damage rating based solely on the percent of leaf area 
consumed (since collard is not a head-producing plant). A damage rating of ? 3 is 
considered marketable under normal conditions (Leibee et al. 1995).   
 For each field season, mean seasonal numbers of larvae and adults of each species 
and mean damage rating at harvest were calculated for each treatment.  Data were 
transformed by using the square-root method ?(x + 0.5) and analyzed for significant 
treatment effects by using analysis of variance (ANOVA) with the replicate plots (or 
subplots) considered as blocks. Means were compared using the Tukey-Kramer HSD 
comparison for all pairs (JMPIN Version 4.0.2, SAS Institute Inc., 1988). Significant 
differences were established at the 95% confidence level (P < 0.05). 
 
3.3 Results 
 
3.3.1 Laboratory experiments. 
  LastCall
TM
 formulations were significantly more toxic to adult P. xylostella and 
T. ni than the double blank formulation both at 2 h and 24 h exposure periods (Table 3.1).  
Approximately 71% of P. xylostella males and 63% of T. ni males were killed within 2 h 
of exposure to conspecific LastCall
TM
 formulations, whereas none of the males exposed 
to the double blank control died within this period. At the end of a 24 h exposure period 
 39
to the formulations, 96% of P. xylostella males and 100% of T. ni males were killed, 
compared to the significantly lower 8% mortality recorded for males of both species 
exposed to the double blank control. 
 
3.3.2 Field evaluation of attracticide formulations 
In general, attracticide formulations provided significant suppression of P. 
xylostella and T. ni populations and crop damage. However, the efficacy of LastCall
TM
 
varied from season to season and was shown to be highly dependent upon the population 
densities of the three lepidopteran species, which also fluctuated from season to season. 
Generally, no significant block effects were detected on any of the key parameters 
(variables), suggesting that the blocks (replicate plots) were similar in pest abundance 
and treatment efficacy.  
In fall 2003, moderate larval infestations (? 0.5 larva per plant per week) of P. 
xylostella and P. rapae were recorded in the cabbage and collard subplots, while T. ni 
larval infestation was very low averaging less than 0.1 larva per plant per week (Figs. 5A 
& 6A). Male P. xylostella capture was relatively low throughout the fall increasing near 
the end of the season (Fig. 7A). Also, low numbers of T. ni were trapped in untreated 
control plots (Fig. 8A), while moderate numbers of adult P. rapae were recorded in 
visual counts (Fig. 9A). Fewer P. xylostella males were captured in pheromone traps 
located in LastCall
TM
 plots (seasonal mean ? SE = 3.4 ? 0.9) than in Bt (seasonal mean ? 
SE = 5.4 ? 0.9) or untreated (seasonal mean ? SE = 6.6 ? 1.4) plots. However, this ~ 49% 
reduction of trap capture in LastCall
TM
 plots relative to untreated plots was not significant 
(F = 2.6, df = 2, P = 0.08). Similarly, trap captures of T. ni in LastCall
TM
 plots were not 
 40
significantly different than captures in the other two treatments (F = 0.1, df = 2, P = 
0.91). Nonetheless, P. xylostella larval counts were significantly lower in cabbage 
subplots treated with LastCall
TM
 or Bt compared to untreated subplots (F = 8.3, df = 2, P 
= 0.0003), whereas no significant differences were recorded among the treatments in 
collard subplots (F = 1.8, df = 2, P = 0.17). Larval counts of T. ni in cabbage and collard 
subplots were too low to detect any significant differences among treatments (cabbage: F 
= 1.0, df = 2, P = 0.37; collard: F = 0.49, df = 2, P = 0.61). As expected, significantly 
lower numbers of P. rapae larvae were found in cabbage and collard subplots treated 
with Bt compared to untreated subplots (cabbage: F = 5.5, df = 2, P = 0.004; collard: F = 
2.9, df = 2, P = 0.05), whereas larval counts were not significantly different between 
LastCall
TM
 subplots and untreated or Bt subplots. Significantly higher damage ratings 
were recorded in untreated subplots than in LastCall
TM
 or Bt subplots (cabbage: F = 14.9, 
df = 2, P < 0.0001; collard: F = 14.5, df = 2, P < 0.0001); marketable cabbage and 
collards were produced in both LastCall
TM
 and Bt subplots, but not in untreated subplots 
(Fig. 10A). 
In spring 2004, P. rapae infestation was very high both in terms of larval pressure 
(Figs. 5B & 6B) and adult visual counts (Fig. 9B). Similarly, high numbers of male P. 
xylostella were captured in pheromone traps (Fig. 7B), while larval pressure was 
moderate (Figs. 5B & 6B). In contrast, T. ni larval pressure was extremely low in the 
subplots (Figs. 5B & 6B), while adult trap catch was virtually zero. Traps captures of 
male P. xylostella in pheromone traps were not significantly different among the three 
treatments (F = 1.0, df = 2, P = 0.36), although slighty lower in LastCall
TM
 plots. 
Significantly higher numbers of P. xylostella larvae were found in untreated cabbage 
 41
subplots than in LastCall
TM
 or Bt subplots (F = 5.6, df = 2, P = 0.0004), whereas 
significant differences were not recorded among the treatments in collard subplots (F = 
2.8, df = 2, P = 0.06). As observed in fall 2003, T. ni infestation was too low to detect any 
significant difference between treatments (cabbage: F = 1.0, df = 2, P = 0.37; collard: F = 
1.0, df = 2, P = 0.37). Expectedly, P. rapae larval counts were significantly lower in 
cabbage and collard subplots treated with Bt compared to untreated or LastCall
TM
 
subplots (cabbage: F = 26.8, df = 2, P < 0.0001; collard: F = 21.7, df = 2, P < 0.0001). 
Damage ratings were significantly higher in untreated and LastCall
TM
 subplots than in Bt 
subplots (cabbage: F = 190, df = 2, P < 0.0001; collard: F = 273, df = 2, P < 0.0001), and 
marketable cabbage and collards were produced only in the Bt subplots (Fig. 10B). 
The results obtained in fall 2004 were generally similar to those of fall 2003 in 
terms of pest pressure, species abundance, and treatment efficacy. In this season, P. 
xylostella and P. rapae pressure was moderate (Figs. 5C, 6C, 7C & 9C). Trichopulsia ni 
larval infestation was not detected in the subplots (Figs. 5C & 6C), although low numbers 
of males were captured in pheromone traps (Fig. 8B). A modest (~ 34%) reduction in trap 
capture was recorded in LastCall
TM
 plots in comparison with untreated control plots, but 
this was not significant (F = 0.15, df = 2, P = 0.87). Similarly, the ~ 43.5% reduction in 
trap capture of T. ni males in LastCall
TM
 plots was not significant (F = 2.3, df = 2, P = 
0.11). Larval counts of P. xylostella were significantly lower in subplots treated with Bt, 
compared to LastCall
TM
 or untreated subplots (cabbage: F = 6.3, df = 2, P = 0.002; 
collard: F = 6.3, df = 2, P = 0.002). Similarly, numbers of P. rapae larvae found in 
subplots treated with Bt were significantly lower than in LastCall
TM
 or untreated subplots 
(cabbage: F = 3.4, df = 2, P = 0.04; collard: F = 5.3, df = 2, P = 0.005). Nevertheless, 
 42
damage ratings were significantly lower in LastCall
TM
 and Bt subplots than in untreated 
subplots (cabbage: F = 3.2, df = 2, P = 0.05; collard: F = 210, df = 2, P < 0.0001); 
marketable crops were produced both in LastCall
TM
 and Bt subplots but not in untreated 
subplots (Fig. 10C). 
In spring 2005, moderate to high infestations of all three species were recorded in 
the subplots both in terms of larval pressure (Figs. 5D & 6D) and adult counts (Figs. 7D, 
4D & 5D), resulting in a relatively higher total pest pressure than in the previous seasons. 
A modest (but not significant) reduction (~ 26%) was recorded in trap captures of male P. 
xylostella was recorded in LastCall
TM
 plots, compared to untreated plots (F = 0.72, df = 
2, P = 0.49). Also, no significant differences in T. ni male trap capture were recorded 
among the treatments (F = 0.02, df = 2, P = 0.98). Seasonal mean numbers of P. 
xylostella larvae were significantly lower in LastCall
TM
 and Bt subplots than in untreated 
subplots (cabbage: F = 8.8, df = 2, P =  0.0002; collard: F = 6.4, df = 2, P =  0.0002). 
Similarly, significantly lower numbers of T. ni larvae were found in cabbage subplots 
treated with LastCall
TM
 or Bt than in untreated subplots (F = 5.8, df = 2, P = 0.003), 
whereas no significant differences were recorded among treatments in collard subplots (F 
= 1.0, df = 2, P =  0.37). For P. rapae, larval counts were significantly lower in subplots 
treated with Bt than in untreated or LastCall
TM
-treated subplots (cabbage: F = 4.6, df = 2, 
P = 0.01; collard: F = 3.2, df = 2, P = 0.04). Significantly lower damage ratings were 
recorded in LastCall
TM
 and Bt subplots than in untreated subplots (cabbage: F = 14.9, df 
= 2, P < 0.0001; collard: F = 14.5, df = 2, P < 0.0001). Marketable cabbage and collards 
were produced in the LastCall
TM
 and Bt subplots, but Bt treatment resulted in a slightly 
 43
better cabbage marketability rating than LastCall
TM
 (Fig. 10D). In general, similar results 
were obtained for cabbage and collard subplots.  
3.4 Discussion 
 The goal of this study was to evaluate the efficacy of attracticide technology as a 
pest management tactic against lepidopteran pests of cole crops. First, we demonstrated 
in laboratory toxicity experiments the effectiveness of both commercial attracticide 
(LastCall
TM
) formulations in killing P. xylostella and T. ni males. The results of our field 
experiments further confirmed the potential utility of both LastCall
TM
 formulations in 
suppression of infestations of P. xylostella and T. ni on cabbage and collards. In the 
current study, LastCall
TM
 provided acceptable control of P. xylostella and T. ni and 
yielded marketable crops similar to Bt in all but one of the four seasons (spring 2004). 
The results show that the efficacy of LastCall
TM
 was dependent upon the population 
densities of the three lepidopteran species, which fluctuated from season to season. In our 
study plots in central Alabama, P. xylostella was observed in moderate numbers in all 
four seasons, while population densities of P. rapae and T. ni were greater in the spring 
than in the fall.  
The failure of LastCall
TM
 in yielding marketable produce in spring 2004 could be 
attributed to several reasons. First, P. xylostella infestation as indicated by adult trap 
captures was 2- to 3-fold greater in spring 2004 than in any of the other seasons (~ 24 
males per trap per week recorded in spring 2004).  In addition, LastCall
TM
 failure may be 
due to the relatively high P. rapae infestation recorded in spring 2004 coupled with the 
fact that this species was not the target of the LastCall
TM
 treatments. Several authors have 
also attributed attracticide failure to very high initial pest populations (Charmillot et al. 
 44
2000, Krukpe et al. 2002, Evenden and McLaughlin 2004b). Krukpe et al. (2002) 
postulated that the effectiveness of attracticide formulations is likely to decrease as the 
population density of female increases, since more females will increase the competition 
provided by natural sources of pheromones. Disruption of sexual communication 
(measured by trap shutdown) has been proposed as a key operative mechanism of the 
attracticide tactic (Mitchell 2002, Evenden and McLaughlin 2004a, b, Evenden et al. 
2005). However, we did not record significant trap shutdown in LastCall
TM
 plots, yet 
LastCall
TM
 was effective in producing marketable cabbage and collards. This suggests 
that elimination of males by the toxicant (permethrin), rather than male confusion or 
interruption of sexual communication due to multiple pheromone sources, was probably 
the main mechanism behind the success of the attracticide tactic in this study 
(Brockerhoff and Suckling 1999, Charmillot et al. 2000).  
Our field study covering four growing seasons each with varying pest pressure 
has yielded some insights on the potential efficacy of the attracticide tactic against 
lepidopteran pests of cole crops and allowed us to make some predictions regarding some 
of the factors that may influence the effectiveness of this relatively novel technology. The 
results of our study suggest that LastCall
TM
, at the recommended application rate of 1600 
droplets per formulation per acre, is effective at low to moderate population densities of 
P. xylostella and T. ni typically observed in the fall in central Alabama. The relatively 
greater spring population densities of P. xylostella and T. ni coupled with extremely high 
P. rapae pressure commonly observed in the spring in central Alabama may likely result 
in the failure of the present pheromone-based attracticide system against lepidopteran 
crucifer pests, which does not target P. rapae. It is possible that the use of a higher 
 45
application rate (e.g., 3000 droplets per formulation per acre) or frequency may likely 
enhance the efficacy of LastCall
TM
 even at high pest population densities; however this 
possibility needs to be investigated. Attracticides utilizing floral attractants instead of 
pheromone are currently under development (IPM Development Company, Marylhurst, 
OR), and may hold promise for utilization against P. rapae. Floral attractants often attract 
both sexes and therefore have the potential to increase the utility of attracticide tactic 
against other species. Furthermore, the development of attracticide formulations that use 
botanical insecticides (e.g., pyrethrum) instead of synthetic insecticides will likely make 
the tactic acceptable to organic farmers, or those interested in sustainable crop 
production. 
In summary, the attracticide technology is potentially effective against 
lepidopteran pests of cole crops and can be of use in an integrated pest management 
program against the cabbage caterpillar complex, either as a stand alone tactic utilizing 
multiple applications within a season or in rotation with Bt or other tactics. The 
advantages of this tactic include species specificity, little or no impact on non-target 
beneficial arthropods, and requirement of less pheromone per acre than mating disruption 
(Charmillot et al. 2000, Mitchell 2002, Evenden and McLaughlin 2004a, b). Additionally, 
because the attracticide technology targets the adult males of these insect populations, it 
is compatible and complementary with tactics aimed at eggs or larvae of P. xylostella and 
T. ni. However, it remains to be seen whether or not this tactic will provide a cost-
effective alternative to Bt or conventional insecticides. 
 
 46
Table 3.1.  Percent mortality of male Plutella xylostella and Trichopulsia ni after 
exposure to attracticide (Last Call 
TM
) or double blank formulations. Twenty four 
males were exposed to each formulation. Percent within the same insect column 
having no letters in common are significant at P < 0.05. 
 
 
% P. xyllostella males dead 
 
% T. ni males dead 
 
Formulation 
treatment 
2 h exposure 24 h exposure 2 h exposure 24 h exposure 
Attracticide 
(Last Call 
TM
) 
70.8 a 95.8 a 62.5 a 100 a 
Double blank 
control 
0 b 8.3 b 0 b 8.3 b 
 
 
 
 
 
 
 
 
 
 
 47
Fall 2003
0
0.2
0.4
0.6
0.8
1
CL DBM ICW
Me
an
 (
?
 SE
)
 
l
a
rvae/
p
l
a
nt
/
w
ee
k
Attracticide
Bt
Untreated control
a
abb
b
b
a
 
Figure 5.a. Seasonal mean (? SE) number of larvae of the three lepidopteran pest species 
sampled per plant per week in cabbage subplots treated with different treatments during 
fall 2003. DBM = diamondback moth, Plutella xylostella; CL = cabbage looper 
Trichopulsia ni; ICW = imported cabbageworm, Pieris rapae. Means followed by the 
same letter are not significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 
 
 
 
 48
Spring 2004
0
0.5
1
1.5
2
CL DBM ICW
M
e
a
n
 (
?
 
S
E
) la
r
v
a
e
/p
la
n
t
/w
e
e
k
Attracticide
Bt
Untreated control
a
a
b
bb
a
a
 
Figure 5.b. Seasonal mean (? SE) number of larvae of the three lepidopteran pest species 
sampled per plant per week in cabbage subplots treated with different treatments during 
spring 2004. DBM = diamondback moth, Plutella xylostella; CL = cabbage looper 
Trichopulsia ni; ICW = imported cabbageworm, Pieris rapae. Means followed by the 
same letter are not significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 
 49
Fall 2004
0
0.2
0.4
0.6
0.8
1
CL DBM ICW
M
e
a
n
 (?
 S
E
) lar
v
a
e
/p
l
a
n
t
/w
e
e
k
Attracticide
Bt
Untreated control
a
a
a
b
b
a
 
Figure 5.c. Seasonal mean (? SE) number of larvae of the three lepidopteran pest species 
sampled per plant per week in cabbage subplots treated with different treatments during 
fall 2004. DBM = diamondback moth, Plutella xylostella; CL = cabbage looper 
Trichopulsia ni; ICW = imported cabbageworm, Pieris rapae. Means followed by the 
same letter are not significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 50
Spring 2005
0
0.2
0.4
0.6
0.8
1
CL DBM ICW
M
e
a
n
 (
?
 
S
E
)
 
la
r
v
a
e
/p
la
n
t
/
w
e
e
k
Attracticide
Bt
Untreated control
a
ab
b
b
b
a
ab
b
a
 
Figure 5.d. Seasonal mean (? SE) number of larvae of the three lepidopteran pest species 
sampled per plant per week in cabbage subplots treated with different treatments during 
fall 2004. DBM = diamondback moth, Plutella xylostella; CL = cabbage looper 
Trichopulsia ni; ICW = imported cabbageworm, Pieris rapae. Means followed by the 
same letter are not significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 
 
 
 
 
 
 
 51
Fall 2003
0
0.2
0.4
0.6
0.8
1
CL DBM ICW
M
e
a
n
 (
?
 S
E
) 
la
r
v
a
e
/
p
la
n
t
/w
e
e
k
Attracticide
Bt
Untreated control
ab
b
a
 
Figure 6.a. Seasonal mean (? SE) number of larvae of the three lepidopteran species 
sampled per plant per week in collard subplots treated with different treatments during 
fall 2003. DBM = diamondback moth, Plutella xylostella; CL = cabbage looper 
Trichopulsia ni; ICW = imported cabbageworm, Pieris rapae. Means followed by the 
same letter are not significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 52
Spring 2004
0
0.5
1
1.5
2
CL DBM ICW
M
e
a
n
 (
?
 S
E
) 
la
r
v
a
e
/
p
la
n
t
/w
e
e
k
Attracticide
Bt
Untreated control
a
b
a
 
Figure 6.b. Seasonal mean (? SE) number of larvae of the three lepidopteran species 
sampled per plant per week in collard subplots treated with different treatments during 
spring 2004. DBM = diamondback moth, Plutella xylostella; CL = cabbage looper 
Trichopulsia ni; ICW = imported cabbageworm, Pieris rapae. Means followed by the 
same letter are not significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 
 53
Fall 2004
0
0.2
0.4
0.6
0.8
1
CL DBM ICW
M
e
a
n
 (
?
 S
E
) 
la
r
v
a
e
/
p
la
n
t
/w
e
e
k
Attracticide
Bt
Untreated control
a
b
ab
a
a
b
 
Figure 6.c. Seasonal mean (? SE) number of larvae of the three lepidopteran species 
sampled per plant per week in collard subplots treated with different treatments during 
fall 2004. DBM = diamondback moth, Plutella xylostella; CL = cabbage looper 
Trichopulsia ni; ICW = imported cabbageworm, Pieris rapae. Means followed by the 
same letter are not significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 
 54
Spring 2005
0
0.2
0.4
0.6
0.8
1
CL DBM ICW
Mean (
?
 
SE
)
 l
a
rvae/
p
l
a
nt
/
w
e
e
k
Attracticide
Bt
Untreated control
a
b
b
 
Figure 6.d. Seasonal mean (? SE) number of larvae of the three lepidopteran species 
sampled per plant per week in collard subplots treated with different treatments during 
spring 2005. DBM = diamondback moth, Plutella xylostella; CL = cabbage looper 
Trichopulsia ni; ICW = imported cabbageworm, Pieris rapae. Means followed by the 
same letter are not significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 
 
 55
Fall 2003
0
5
10
15
20
25
10/4 10/11 10/18 10/25 11/1 11/8 11/15
Me
a
n
 (
?
 SE
)
 D
B
M m
a
l
e
s
/
Attracticide
Bt spray
Untreated Control
 
Figure 7.a. Mean (? SE) trap capture of diamondback moth (DBM), Plutella xylostella  
in pheromone baited wing traps for each of three treatments fall 2003. 
 
 
 
 
 
 
 
 56
Spring 2004
0
10
20
30
40
50
60
4/8 4/15 4/22 4/29 5/6 5/13 5/20 5/27 6/3 6/10
Me
a
n
 (?
 S
E
) D
B
M
 m
a
l
e
s
/
Attracticide
Bt Spray
Untreated Control
 
Figure 7.b. Mean (? SE) trap capture of diamondback moth (DBM), Plutella xylostella  
in pheromone baited wing traps for each of three treatments spring 2004. 
 
 
 
 
 
 
 
 57
 Fall 2004
0
5
10
15
20
10/9 10/16 10/23 10/30 11/6 11/13 11/20 11/27 12/4
M
e
a
n
 (?
 
S
E
) D
B
M
 ma
l
e
s
/
Attracticide
Bt Spray
Untreated Control
 
Figure 7.c. Mean (? SE) trap capture of diamondback moth (DBM), Plutella xylostella  
in pheromone baited wing traps for each of three treatments fall 2004. 
 
 
 
 
 
 
 
 
 58
 Spring 2005
0
10
20
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4/28 5/5 5/12 5/19 5/26 6/2 6/9 6/16 6/23
M
e
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Attracticide
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Figure 7.d. Mean (? SE) trap capture of diamondback moth (DBM), Plutella xylostella  
in pheromone baited wing traps for each of three treatments spring 2005. 
 
 
 
 
 
 
 
 
 59
 Fall 2003
0
1
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10/3 10/10 10/17 10/24 10/31 11/7 11/14
M
e
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Attracticide
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Figure 8.a. Mean (? SE) trap capture of cabbage looper (CL), Trichopulsia ni in 
pheromone baited wing traps for each of three treatments during fall 2003. 
 
 
 
 
 
 
 
 60
Fall 2004
0
2
4
6
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M
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Attracticide
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Figure 8.b. Mean (? SE) trap capture of cabbage looper (CL), Trichopulsia ni in 
pheromone baited wing traps for each of three treatments during spring 2004. 
 
 
 
 
 
 
 
 
 61
Spring 2005
0
5
10
15
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4/30 5/7 5/14 5/21 5/28 6/4 6/11 6/18 6/25
M
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Attracticide
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Figure 8.c. Mean (? SE) trap capture of cabbage looper (CL), Trichopulsia ni in 
pheromone baited wing traps for each of three treatments during spring 2005. 
 62
 Fall 2003
0
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10/6 10/13 10/20 10/27 11/3 11/10 11/17
M
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Attracticide
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Untreated Control
 
Figure 9.a. Mean (? SE) number of adult imported cabbageworm (ICW), Pieris rapae 
counted during 5-min observation period in untreated and treated plots during fall 2003. 
 
 
 
 
 
 
 
 
 
 63
Spring 2004
0
10
20
30
40
50
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4/10 4/17 4/24 5/1 5/8 5/15 5/22 5/29 6/5
Me
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Attracticide
Bt Spray
Untreated Control
 
Figure 9.b. Mean (? SE) number of adult imported cabbageworm (ICW), Pieris rapae 
counted during 5-min observation period in untreated and treated plots during spring 
2004. 
 
 64
Fall 2004
0
1
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3
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10/11 10/18 10/25 11/1 11/8 11/15 11/22 11/29 12/6
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Attracticide
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Untreated Control
 
Figure 9.c. Mean (? SE) number of adult imported cabbageworm (ICW), Pieris rapae 
counted during 5-min observation period in untreated and treated plots during fall 2004. 
 
 
 
 
 
 
 
 65
 Spring 2005
0
5
10
15
20
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4/25 5/2 5/9 5/16 5/23 5/30 6/6 6/13 6/20 6/27
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Attracticide
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Figure 9.d. Mean (? SE) number of adult imported cabbageworm (ICW), Pieris rapae 
counted during 5-min observation period in untreated and treated plots during spring 
2005. 
 66
Fall 2003
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Cabbage Collards
M
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(
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Attracticide
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Untreated Control a
a
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Figure 10.a. Mean (? SE) damage ratings of plants harvested from plots of each of three 
treatments in fall 2003. Line indicates marketability threshold of 3 above which produce 
is considered unmarketable (Leibee 1995). Means followed by the same letter are not 
significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 
 
 
 
 67
Spring 2004
0
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Cabbage Collards
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b
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a
 
Figure 10.b. Mean (? SE) damage ratings of plants harvested from plots of each of three 
treatments in spring 2004. Line indicates marketability threshold of 3 above which 
produce is considered unmarketable (Leibee 1995). Means followed by the same letter 
are not significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 
 
 
 
 
 68
Fall 2004
0
1
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Cabbage Collards
M
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 r
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ti
n
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Attracticide
Bt Spray
Untreated Control
a
a
ab
bb
b
 
Figure 10.c. Mean (? SE) damage ratings of plants harvested from plots of each of three 
treatments in fall 2004. Line indicates marketability threshold of 3 above which produce 
is considered unmarketable (Leibee 1995). Means followed by the same letter are not 
significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 
 
 
 
 
 69
Spring 2005
0
1
2
3
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Cabbage Collards
M
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Attracticide
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a a
b
b
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c
b
 
Figure 10.d. Mean (? SE) damage ratings of plants harvested from plots of each of three 
treatments in spring 2005. Line indicates marketability threshold of 3 above which 
produce is considered unmarketable (Leibee 1995). Means followed by the same letter 
are not significantly different (P < 0.05, Tukey-Kramer HSD).
 
 
 
 
 70
CHAPTER IV : 
EVALUATION OF SEVERAL REDUCED-RISK INSECTICIDES IN 
COMBINATION WITH AN ACTION THRESHOLD FOR MANAGING 
LEPIDOPTERAN PESTS OF COLE CROPS IN ALABAMA 
 
4.1 Introduction 
Cole crops, Brassica oleracea (L.), including cabbage, collards, broccoli, kale, 
brussels sprouts, and cauliflower, are an important component of diets in many parts of 
the world.    
Cabbage and collards are the key cole crops grown in Alabama. Growers in the state 
utilize both spring and fall plantings for both crops, and often grow them in rotation with 
other vegetables (Kemble 1999).  The key lepidopteran pests of cole crops in Alabama 
include the diamondback moth, Plutella xylostella (L.), imported cabbageworm, Pieris 
rapae (L.), and cabbage looper, Trichoplusia ni (H?bner) (Kemble 1999).  Plutella 
xylostella and P. rapae are often the most abundant pests in many parts of Alabama, 
while infestations of T. ni are sporadic in nature (personal observation).  
Caterpillars of the three lepidopteran species do direct damage to the marketable 
part of the plant by chewing holes in the foliage and producing frass (Harcourt et al. 
1955; Shelton et al. 1982; Talekar & Shelton 1993; Tabashnik 1994), and are usually 
managed as a single caterpillar complex (Mahr et al. 1993). Tolerance of damage from 
 71
these caterpillars is extremely low, basically zero to trace amounts of insect 
damage or frass in the final product (Morisak et al. 1984). In order to avoid significant 
economic loss, vegetable producers have typically managed these pests using an 
expensive therapeutic approach involving calendar-based applications of conventional 
insecticides, including various organophosphate, carbamate, and pyrethroid formulations. 
For instance, approximately 30,000 pounds of insecticide active ingredient are utilized 
annually for collard production in Alabama (Williams & Dangler 1992). Excessive and 
indiscriminate use of conventional insecticides has resulted in the development of pest 
resistance to insecticides (Hines & Hutchison 2001; Liu et al. 2002).  
Globally, formulated sprays of microbial insecticides such as Bacillus 
thuringiensis and spinosad have been widely used as an alternative to chemical 
insecticides. However, development of pest resistance to microbial insecticides has been 
reported in several locations. For instance, resistance to Bacillus thuringiensis subspecies 
kursatki have been detected in field populations of P. xylostella in various locations in the 
mainland U.S. (Mahr et al. 1993; Shelton et al. 1993; Tang et al. 1997), and in several 
other locations throughout the world including Hawaii, Malaysia, the Philippines, Japan, 
Central America, and Thailand (Talekar & Shelton 1993; Rueda & Shelton, 1995; 
Tabashnik 1997). Similarly, field populations of P. xylostella collected in Malaysia have 
been reported to show resistance to spinosad (Sayyed 2004).  The problem of insecticide 
resistance is not limited to P. xylostella. Resistance to B. thuringiensis has been 
demonstrated in laboratory populations of T. ni (Estada & Ferre 1994) and in greenhouse 
populations in British Columbia (Janmaat & Myers 2003).   
 72
Traditionally, more attention has been paid to insecticide-based control programs 
than biological control for management of lepidopteran pests of cole crops (Taleker & 
Shelton 1993, Biever et al. 1994, Xu et al. 2004).  Although successful integrated pest 
management (IPM) programs have been developed and implemented in many parts of the 
world (Biever et al. 1994), it appears that insecticide-based control will remain the major 
tactic for managing caterpillar pests of cole crops for the foreseeable future  (Xu et al. 
2004).  
Over the past several years, numerous biologically-based insecticides with novel 
modes of action have been developed and shown to have a high level of efficacy on 
lepidopteran pests of cole crops (Eger & Lindenbery 1998; Liu and Sparks 1999, Hill & 
Foster 2000; Hines & Hutchison, 2001). These include microbial insecticides (e.g., 
several formulations of spinosad and B. thuringiensis) and insect growth regulators. 
These new materials are termed ?reduced-risk insecticides? because of their narrow 
spectrum of activity and low toxicity to humans and non-target organisms, and are 
considered IPM-compatible. Although reduced-risk insecticides are increasingly being 
used by vegetable growers worldwide, little has been done to evaluate these materials in 
Alabama. The objective of this study was to evaluate the efficacy of several reduced-risk 
insecticides against lepidopteran pests of cole crops in Alabama. The materials evaluated 
included three formulations of B. thuringiensis (Dipel?, XenTari?, and Dipel+XenTari 
mixture) (Valent Biosciences Libertyville, IL), Entrust? (Dow AgroSciences, 
Indianapolis, IN), and Novaluron (Crompton (now Chemtura), Middlebury, CT).  Dipel? 
is a formulation of B. thuringiensis subspecies kursatki and is the most commonly used 
microbial insecticide on Alabama vegetable crops (Joseph Kemble, personal 
 73
communication). XenTari? is a formulated spray of B. thuringiensis subspecies aizawai, 
while Dipel+XenTari is a premixed test formulation consisting of both subspecies of B. 
thuringiensis.  Entrust? is a naturalyte insect control product formulated for the organic 
grower. The active ingredient, spinosad, is developed from a fermentation by-product of 
the soil-borne actinomycete bacterium, Saccharopolyspora spinosa (Liu et al. 1999). 
Novaluron is an insect growth regulator (IGR) that works by inhibiting chitin synthesis. It 
is currently labeled in the U.S. as Diamond? for use on cotton and Rimon? for use on 
apples, potatoes and sweet potato, and the registrant plans to label Novaluron for use on 
cole crops in the near future (K. Griffith, personal communication). These materials were 
evaluated over multiple field seasons (2004-2005) in central Alabama. 
 
4.2 Materials and Methods 
4.2.1 General Methodology 
 This research was conducted over three growing seasons; spring 2004, fall 2004, 
and spring 2005 at the E.V. Smith Agricultural Research Station in Shorter, AL.  
Treatments were arranged in a randomized complete block design with three replicates in 
each spring season and four in the fall 2004 season.  All seedlings were obtained from a 
nursery in western Georgia (Lewis Taylor Farms; Ty Ty, Georgia) and were planted 
bareground following a preseason fire ant (Solenopis invicta) treatment with Amdro? 
(active ingredient = hydramethylnon, BASF Corporation, Research Triangle Park, NC).  
Standard field preparation and crop production practices (i.e., irrigation) were used to 
establish cabbage or collard plants in all three field seasons. 
 74
 In spring of 2004 ?Bravo? cabbage was mechanically transplanted on 30 March 
2004.  Plots were 13.7 m by 9.1 m with plants spaced 45 cm apart within a row and 90 
cm between rows for a total of 300 plants per plot. Plots were separated by a 15.2 m 
alley.  The following four reduced-risk insecticides were compared: Dipel?, Xentari?, 
Dipel+Xentari combination, and Entrust?. In fall 2004, ?Top bunch? collards were 
mechanically transplanted 2 October 2004.  Plots consisted of two 10?m rows, 100 cm 
apart with plants spaced 45 cm apart within a row and 90 cm between rows for a total of 
40 plants per plot.  Five reduced-risk insecticides were compared: Dipel?, Xentari?, 
Dipel+Xentari combination, Entrust?, and Novaluron. In spring 2005, ?Vates? collards 
were mechanically transplanted at the E.V. Smith Agricultural Research Station on 22 
April 2005.  The plot dimensions and treatments evaluated were as described for fall 
2004. 
 Plots were evaluated weekly for pest infestation by sampling ten randomly 
selected plants per plot for larvae of P. xylostella, P. rapae, and T. ni. Eggs and pupae of 
the three species were also sampled. The number of immatures of each species was 
calculated by summing the number of larvae and pupae. Treatment applications were 
made only when larval counts exceeded a threshold of 0.5 cabbage looper equivalents 
(CLE) per plant (Shelton et al., 1982; 1983). The CLE method accounts for the varying 
levels of feeding damage caused by the three species. In this method, 1 CLE = 20 P. 
xylostella larvae = 1.5 P. rapae larva = 1 T. ni larva (Shelton et al., 1982; 1983). In 
addition, plants were also sampled for aphids (number of plants with aphid infestation) 
and key non-target predatory insects in our fields, mainly spiders and lady beetle adults 
(Coccinelidae). Treatment applications were made with a CO
2
 pressurized backpack 
 75
sprayer using a 3-ft boom with 3 nozzles calibrated to deliver about 25 gpa at 40 psi.  
Insecticides were applied at the recommended rates. Dipel?, Xentari?, and 
Dipel+Xentari were applied at the rate of 1 pound per acre, Entrust? at 2 oz per acre, and 
Novaluron applied at the rate of 12 fluid ounces per acre. Using the action threshold of 
0.5 CLE, the average number of insecticide applications varied by treatment and season 
and ranged from 1.3 to 5 applications per season (Table 4.1). 
  At harvest, ten plants were randomly selected from each plot and rated for 
caterpillar feeding damage and marketability was quantified using the method of Greene 
et al. (1969). In this method cabbage plants grown in spring 2004 were rated based on 
insect feeding damage on a scale of 1 to 6 as follows:  1 = no apparent insect damage on 
head or inner wrapper leaves; 2 = no head damage, but minor feeding on wrapper leaves 
with 0-1% leaf area consumed; 3 = no damage on head, but moderate feeding damage on 
wrapper leaves with 2-5% leaf area consumed; 4 = minor feeding on head (but no feeding 
through outer head leaves), but moderate feeding on wrapper or outer leaves with 6-10% 
leaf area consumed; 5 = moderate to heavy feeding damage on wrapper and head leaves 
and a moderate number of feeding scars on head with 11-30% leaf area consumed; and 6 
= severe feeding damage to head and wrapper leaves  with heads having numerous 
feeding scars with ? 30% leaf area consumed (Greene et al. 1969). A similar method was 
used to assess marketability of collards in fall 2004 and spring 2005 with damage rating 
based solely on the percent of leaf area consumed (since collards is not a head-producing 
plant). A damage rating of ? 3 is considerable marketable under normal conditions, 
whereas a damage rating of ? 4 is marketable under exceptional market conditions 
(Leibee et al., 1995).   
 76
4.2.2 Statistical Analysis   
For each season, mean seasonal larval and immature counts of each lepidopteran 
species, number of plants with aphid infestation, numbers of key non-target beneficial 
arthropods (i.e., spiders and lady beetle adults), and mean damage rating at harvest were 
calculated for each treatment. Data were transformed using the square-root method ?(x + 
0.5) and analyzed for significant treatment effects by using analysis of variance 
(ANOVA) with the plots considered as blocks. Means were compared using the Tukey-
Kramer HSD comparison for all pairs (JMPIN Version 4.0.2, SAS Institute Inc., 1988). 
Significant differences were established at the 95% confidence level (P < 0.05). 
 
4.2 Results 
Infestation levels of the three lepidopteran pests varied with growing season. Moderate to 
high populations of P. xylostella and P. rapae were recorded during all three field 
seasons, while T. ni population was recorded only in spring 2005.  In general, relatively 
higher populations of the lepidopteran pests were recorded in both spring seasons 
compared with the fall season. This was also reflected in the number of applications per 
insecticide treatment made during each season which averaged 3.2, 1.3, and 4.3 for spring 
2004, fall 2004, and spring 2005, respectively (Table 4.1). In both spring seasons, 
caterpillar pest pressure as measured by CLE per plant per week in untreated control plots 
began two weeks after planting and moderate caterpillar pressure was observed through 
harvest in spring 2004 (Fig. 11). Extremely high caterpillar pressure was recorded late in 
spring 2005 with CLEs greater than 3.5 per plant per week recorded in the last two weeks 
of the season (Fig. 11). In the lone fall season (fall 2004), however, caterpillar pest 
 77
infestation did not commence until six weeks after planting averaging less than 0.5 CLE 
per plant per week for the remainder of the season (Fig. 11). In general, no significant 
block (plot) effects were detected (P > 0.005) for any of the dependent variables in any of 
the seasons, suggesting that the plots were similar in pest abundance and treatment 
efficacy. 
In spring 2004, all four reduced-risk insecticides resulted in significant reductions in 
the number of P. xylostella larvae (F = 9.5, df = 4, P = < 0.0001) and immatures (F = 8.9, 
df = 4, P = < 0.0001), and P. rapae larvae (F = 3.3, df = 4, P = < 0.0001) and immatures 
(F = 20.3, df = 4, P = < 0.0001) compared with the untreated control (Fig. 12A). 
However, significantly higher numbers of P. rapae immatures were recorded for Dipel? 
compared with the other insecticide treatments. Significantly higher damage ratings were 
recorded in untreated control plots than in any of the treatments (F = 65.3, df = 4, P = < 
0.0001; Fig. 13A). Comparing the treatments, mean damage ratings were significantly 
lower in Entrust? than in Dipel+Xentari combination. No significant effects of 
insecticide treatments were recorded in the number of plants with aphids (F = 0.3, df = 4, 
P = 0.89), and in the numbers of spiders (F = 0.7, df = 4, P = 0.62) or lady beetles (F = 
1.2, df = 4, P = 0.30) found per plant (Fig. 14A). 
In fall 2004, a significant treatment effect was recorded for P. xylostella larvae (F = 
2.3, df = 5, P = 0.04). However, only Entrust? resulted in significant reduction in P. 
xylostella larvae compared with the untreated control; no significant differences were 
recorded for the other treatments (Fig. 12B). With the exception of Dipel?, all treatments 
significantly reduced P. xylostella immatures (F = 4.4, df = 5, P = 0.0006) and P. rapae 
larvae (F = 5.3, df = 5, P < 0.0001).  Nonetheless, a significantly higher density of P. 
 78
rapae immatures was recorded in the untreated control than in any of the treatments (F = 
11.3, df = 5, P < 0.0001). All five treatments had significantly lower mean damage 
ratings in comparison with the untreated control (F = 38.7, df = 5, P < 0.0001; Fig. 13B). 
No significant effects of treatments were recorded in the number of plants with aphids (F 
= 1.8, df = 4, P = 0.10), and in the numbers of spiders (F = 1.5, df = 4, P = 0.20) or lady 
beetles (F = 0.7, df = 4, P = 0.62) found per plant (Fig. 14B). 
In spring 2005, T. ni was collected in the field, whereas it was not present during the 
previous two seasons (Fig. 12C). In general, all treatments resulted in significant 
reductions in pest populations (Fig. 12C). All treatments except Dipel? significantly 
reduced densities of T. ni larvae (F = 3.3, df = 5, P = 0.006) and immatures (F = 3.7, df = 
5, P = 0.003) compared with the untreated control (Fig. 12C). For P. xylostella, 
significantly lower numbers of larvae (F = 8.1, df = 5, P < 0.0001) and immatures (F = 
9.7, df = 5, P < 0.0001) were recorded for all treatments compared with the untreated 
control. Similar significant treatment effects were recorded for P. rapae larvae (F = 3.9, 
df = 5, P = 0.002) and immatures (F = 4.1, df = 5, P = 0.001); however P. rapae larval 
counts in plots treated with the Dipel+Xentari formulation were not significantly lower 
than larval counts in untreated control plots (Fig. 12C). A mean damage rating of 5.4 was 
recorded in the untreated control which was significantly higher (F = 101.4, df = 5, P < 
0.0001) than damage ratings in any of the five treatments (Fig. 13C). In all three seasons, 
mean damage ratings recorded in the treated plots were never above the marketability 
threshold of 3 (Green et al. 1969). No significant differences were recorded among the 
treatments in the number of plants with aphids (F = 0.26, df = 4, P = 0.93), numbers of 
spiders per plant (F = 1.2, df = 4, P = 0.30), and numbers of lady beetles per plant (F = 
 79
0.8, df = 4, P = 0.55) (Fig. 14C), suggesting little or no effects of insecticide treatments 
on the key non-target predators in our plots. 
4.3 Discussion 
The goal of this study was to evaluate the efficacy of various reduced-risk 
insecticides in providing acceptable control of lepidopteran pests of cole crops in 
Alabama.  In all three seasons, all materials tested resulted in the production of 
marketable produce with considerably lower pest pressure and crop damage ratings 
compared with untreated control plots which never yielded marketable produce.  These 
results indicate that all five reduced-risk insecticides were effective in controlling 
lepidopteran pests of cole crops in Alabama. The results also suggest that the 0.5 CLE 
action threshold recommended by Shelton et al. (1982, 1983) can be used to produce 
marketable cabbage and collards in Alabama with only minimal applications of reduced-
risk insecticides, particularly in locations with minor or no endemic populations of T. ni. 
Although resistance evaluation was not the primary goal of this study, our results 
confirming the high efficacy of the various microbial insecticides tested in this study may 
suggest that P. xylostella resistance to B. thuringiensis is currently not a major problem in 
central Alabama, considering that vegetable growers in this region have been applying 
Dipel? in their fields for years. 
Although we did not always find significant differences among the reduced-risk 
insecticides tested in this study, Entrust? consistently produced the lowest mean damage 
ratings (although not always significant) with the least mean number of applications per 
season (Table 4.1). The relatively higher efficacy of Entrust? recorded in this study may 
be due to its broad spectrum of activity and multiple mode of entry. Entrust? differs from 
 80
the other materials evaluated in this study in that it successfully kills insects from several 
orders, whereas the other treatments are selective to lepidopterans only (Cisneros 2002). 
In addition, spinosad, the active ingredient in Entrust? has both contact and ingestion 
activity (Eger & Lindenber 1998; Liu et al. 1999), whereas the other reduced-risk 
insecticides must be eaten by the insects in order to be effective.  It is thought that the 
broad spectrum activity of Entrust? will probably ensure some control of non-
lepidopteran pests such as cruciferous flea beetles, harlequin bugs, aphids, and other 
minor pests that the other chemicals were not effective against. However, we did not 
observe in the current study a significant reduction in aphid-infested plants in Entrust?-
treated plots compared to the other treatments or control. On the other hand, spinosad has 
also been reported as toxic to beneficial insects such as Diadegma insulare (Cressons) 
(Hymenoptera: Ichneumonidae) (Xu et al. 2004), a very common and effective parasitoid 
of P. xylostella in North America (Mahr et al. 1993).  Hill & Foster (2000) showed a 
100% D. insulare mortality rate after 8 hours of exposure to spinosad-treated brassica 
leaves, while Cisneros et al. (2002) recorded up to 98% mortality of predators exposed to 
high concentrations of this microbial insecticide. However, we did not record any 
significant effect of Entrust? or any of the other treatments on numbers of spiders and 
lady beetles, the two most important predators in our fields. Entrust? thus appears to be a 
promising tool for use in cole crop pest management and insecticide resistance 
management programs, considering that the active ingredient, spinosad has not been 
reported to share cross-resistance mechanisms with any other group of insecticides (Liu 
& Yue 2000, Wei et al. 2001). In general, Xentari? was second to Entrust? in producing 
acceptable damage ratings. However, the fact that this material had the highest average 
 81
number of applications per season suggests that it may not provide economically 
acceptable control compared to the other treatments. 
Significant variations in the populations of the three lepidopteran pests were 
recorded from season to season. In general, lepidopteran pest pressure was higher in both 
spring seasons than in the fall. Significant P. xylostella pressure was recorded in both 
spring seasons and in the fall, whereas P. rapae pressure was highest in spring 2004 
followed by spring 2005. Furthermore, we recorded during spring 2004 ~ 60 flying P. 
rapae adults per plot in 5-min visual observations compared to ~ 8 flying adults in fall 
2004, suggesting that this pest may be more severe in the spring than in the fall. The 
detection of T. ni in spring 2005 may have exacerbated total pest pressure during this 
season resulting in above threshold CLEs and the need to apply insecticides at a much 
higher frequency than in the first two seasons. This is especially likely since T. ni is the 
most voracious and damaging of the three pests (Shelton et al. 1982; Hines & Hutchison 
2003).  The reason for the detection of T. ni only in spring 2005 may be due to later 
planting date for this season. In summary, our results confirmed the efficacy of the tested 
reduced-risk insecticides in managing direct pests of cole crops in Alabama in a 
threshold-based IPM program. These reduced-risk insecticides offer a wide range of pest 
management options available to vegetable growers and should be used wisely or in 
rotation with one another to minimize selection for resistance to any one given material. 
Obviously, the longevity of these new insecticides as effective IPM tools will depend on 
their judicious use, compatibility with natural enemies, and cost effectiveness, among 
other factors.   
 
 82
Table 4.1.  Mean number of applications of each reduced-risk insecticide treatment 
per plot during each season. Treatment applications were made only when weekly 
larval counts exceeded a threshold of 0.5 cabbage looper equivalents (CLE) per 
plant.                  
Treatment/      
Formulation  Spring 2004  Fall 2004  Spring 2005       
  
Dipel DF  2.67 ? 0.19  1.50 ? 0.14  4.33 ? 0.19 
Xentari DF  2.33 ? 0.19  1.25 ? 0.13  5.00 ? 0.00 
Dipel+Xentari DF 2.67 ? 0.19  1.25 ? 0.13  4.67 ? 0.19 
Entrust 80WP  2.33 ? 0.19  1.25 ? 0.13  3.67 ? 0.29 
Novaluron        ---   1.25 ? 0.13  4.00 ? 0.00 
 
 
 
 
 
 83
0
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Weeks after planting
Me
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Spring 2004
Fall 2004
Spring 2005
 
Figure 11. Caterpillar pressure expressed as mean (? SE) number of cabbage looper 
equivalents (CLE) per plant recorded weekly after planting in untreated control plots 
during spring 2004, fall 2004, and spring 2005. Planting dates for spring 2004, fall 2004, 
and spring 2005 were March 30 2004, October 2 2004, and April 22 2005, respectively. 
 
 
 
 
 
 
 
 
 
 84
 
Spring 2004
0.0
0.5
1.0
1.5
2.0
2.5
CL larvae CL immatures DBM larvae DBM immatures ICW larvae ICW immatures
M
e
an
 (
?
 S
E
)
 #/
p
l
an
t
/
w
e
e
k
Dipel
Xentari
Dipel+Xentari
Entrust
Untreated Check
a
a
a
a
c
b
b
b
b
b
bb
b
b
bb
b
b
c
c
 
Figure 12.a. Seasonal mean (? SE) number of larvae and immatures of lepidopteran 
species sampled per plant per week in plots treated with different reduced-risk 
insecticides during spring 2004. Key: CL = cabbage looper (Trichopulsia ni); DBM = 
diamondback moth (Plutella xylostella); ICW = imported cabbageworm (Pieris rapae). 
Means followed by the same letter are not significantly different (P < 0.05, Tukey-
Kramer HSD). 
 
 
 
 
 
 
 
 
 85
Fall 2004
0.0
0.5
1.0
1.5
2.0
2.5
CL larv ae CL immatu res DBM larvae DBM immatures ICW  larv ae ICW  immatures
Me
a
n
 (
?
 SE
)
 #
/
pl
a
n
t
/
w
e
e
k
Dipel
Xentari
Dipel+Xentari
Entrust
Novaluron
Untreated Check
a
a
b
bb
b
b
b
ab
abab
ab
b
a
a
ab
ab bbbbb bb
 
Figure 12.b. Seasonal mean (? SE) number of larvae and immatures of lepidopteran 
species sampled per plant per week in plots treated with different reduced-risk 
insecticides during fall 2004. Key: CL = cabbage looper (Trichopulsia ni); DBM = 
diamondback moth (Plutella xylostella); ICW = imported cabbageworm (Pieris rapae). 
Means followed by the same letter are not significantly different (P < 0.05, Tukey-
Kramer HSD). 
 
 
 
 
 
 
 
 
 86
Spring 2005
0.0
0.5
1.0
1.5
2.0
2.5
CL larvae CL immatures DBM larvae DBM immatures ICW larvae ICW immatures
M
e
an
 (
?
 S
E
)
 #/
p
l
an
t
/
w
e
e
k
Dipel
Xentari
Dipel+Xentari
Entrus t
Novaluron
Untreated Check
a
a
a
a
b
ab b
bbb babbb bb
b
b
b
b
bb
bb
a
a
b
ab b
b
bbb
b b
 
Figure 12.c. Seasonal mean (? SE) number of larvae and immatures of lepidopteran 
species sampled per plant per week in plots treated with different reduced-risk 
insecticides during spring 2005. Key: CL = cabbage looper (Trichopulsia ni); DBM = 
diamondback moth (Plutella xylostella); ICW = imported cabbageworm (Pieris rapae). 
Means followed by the same letter are not significantly different (P < 0.05, Tukey-
Kramer HSD). 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 87
Spring 2004
0
1
2
3
4
5
6
Dipel Xentari Dipel+Xentari Entrust Untreated Check 
Me
a
n
 (
?
 S
E
)
 
d
a
mag
e
 r
a
t
i
n
g
a
b
bc
bc
c
 
Figure 13.a. Mean (? SE) damage ratings of plants harvested from plots treated with 
different reduced-risk insecticides during spring 2004. Line indicates marketability 
threshold of 3 above which produce is considered unmarketable. Means followed by the 
same letter are not significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 
 
 
 
 
 
 
 
 
 
 
 
 88
Fall 2004
0
1
2
3
4
5
6
Dipel Xentari Dipel+Xentari Entrust Novaluron Untreated
Check 
M
e
a
n
 (?
 S
E
) d
a
m
a
g
e
 
r
a
t
i
n
g
a
b
bbb
b
 
Figure 13.b. Mean (? SE) damage ratings of plants harvested from plots treated with 
different reduced-risk insecticides during fall 2004. Line indicates marketability threshold 
of 3 above which produce is considered unmarketable. Means followed by the same letter 
are not significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 
 
 
 
 
 
 
 
 
 
 
 
 89
Spring 2005
0
1
2
3
4
5
6
Dipel Xentari Dipel+Xentari Entrust Novaluron Untreated
Check 
M
e
a
n
 (
?
 SE
)
 da
m
a
g
e
 ra
t
i
n
g
a
b
bb
b
b
 
Figure 13.c. Mean (? SE) damage ratings of plants harvested from plots treated with 
different reduced-risk insecticides during spring 2005. Line indicates marketability 
threshold of 3 above which produce is considered unmarketable. Means followed by the 
same letter are not significantly different (P < 0.05, Tukey-Kramer HSD). 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 90
0
0.02
0.04
0.06
0.08
Spiders Lady beetles
M
e
a
n
 (?
 S
E
) #
/
p
l
a
n
t/
w
e
e
k
Dipel
Xentari 
Dipel+Xentari
Entrus t
Untreated Check
Spring 2004
 
 
Figure 14.a. Seasonal mean (? SE) number of non-target spiders and lady beetle adults 
found per plant per week in plots treated with different reduced-risk insecticides during 
spring 2004.  Means are not significantly different (P > 0.05, Tukey-Kramer HSD). 
 
 
 
 
 
 
 
 
 
 
 
 
 
 91
0
0.02
0.04
0.06
0.08
Spiders Lady beetles
M
e
a
n
 (?
 S
E
) #
/
p
l
a
n
t/
w
e
ek
Dipel
Xentari
Dipel+Xentari
Entrus t
Novaluron
Untreated Check
Fall 2004
 
 
Figure 14.b. Seasonal mean (? SE) number of non-target spiders and lady beetle adults 
found per plant per week in plots treated with different reduced-risk insecticides during 
fall 2004.  Means are not significantly different (P > 0.05, Tukey-Kramer HSD). 
 
 
 
 
 
 
 
 
 
 
 
 
 
 92
0
0.02
0.04
0.06
0.08
Spiders Lady beetles
Me
a
n
 (?
 S
E
) #
/
p
l
a
n
t/
w
e
e
k
Dipel
Xentari 
Dipel+Xentari
En trus t
Novaluron
Untreated Check
Spring 2005
 
 
Figure 14.c. Seasonal mean (? SE) number of non-target spiders and lady beetle adults 
found per plant per week in plots treated with different reduced-risk insecticides during 
spring 2005.  Means are not significantly different (P > 0.05, Tukey-Kramer HSD). 
 
 
 93
COMBINED REFERENCES CITED 
 
Alabama Agricultural Statiscs Service (AASS) 2003. pp 94. 
Al-Doghairi, M.A., W.S. Cranshaw.  2004.  The effect of interplanting of necteriferous 
plants on the population density and parasitism of cabbage pests.  Southwestern 
Entomologist. 29 (1) 61-68. 
Andalaro, J.T., C.W. Hoy, K.B. Rose, A.M. Shelton. 1983. Evaluation of Insecticide 
Usage in the New York Procession-Cabbage Pest Management Program. Journal 
of Economic Entomology. 76:1121-1124. 
Baker, P.B., A.M. Shelton, and J.T. Andale. 1982. Monitoring of Diamondback moth 
(Lepidoptera: Plutellidae) in cabbage with pheromones. Journal of Economic 
Entomology 75:1025-1028. 
Bennett, K.V.W. Burkness, E.C., and Hutchinson, W.D. 2000.  Cabbage Maggot.  
University of Minnesota Extension Service.  
http://vegedge.umn.edu/vegpest/colecrop/cabmag.htm . 
Berger, R.S. 1966.  Isolation, identification and synthesis of the sex attractant of the 
cabbage looper, Trichoplusia ni.  Ann. Entomol. Soc. Am. 59: 767-771. 
Biever, K.D. 1972. Reliability of climate-simulation studies utilizing Pieris rapae (L.) 
Environ Entomol. 1: 194-197.
 
 94
Biever K.D., R.L. Chauvin, G.L. Reed, R.C. Wilson, 1991. Seasonal occurrence and 
abundance of lepidopterous pests and associated parasitoids on collards in the 
northwestern United States. J Econ Science. 27(1) 5-17. 
Biever, K.D., D.L. Hostetter D.L and J.R. Kern. 1994. Evolution and implementation 
of a biological control IPM system for crucifers: 24-year case history. American 
Entomologist. 40:103-108. 
Bjostad, L.B., C.E. Linn, L.-W. Du, and W. L. Roelofs. 1984.  Identification of new 
sex pheromone components in Trichoplusia ni predicted in biosynthetic 
precursors. Ann. Entomol. Soc. Am. 59: 767-771. 
Brockerhoff, E.G., and D.M Suckling. 1999. Development of an attracticide against 
lightbrown apple moth (Lepidoptera: Tortricidae). J. Econ. Entomol. 92:853-859. 
Charmillot, P.J., and D. Hofer. 1997. Control of the codling moth, Cydia pomonella L., 
by an attract and kill formulation. Technology transfer in mating disruption. 
IOBC WPRS Bull. 20: 139-140. 
Charmillot, P.J, D. Hofer, and D. Pasquier. 2000. Attract and Kill: a new methold for 
control of the codling moth, Cydia Pomonella. Entomologia Experimentalis at 
Applicata 94: 211-216. 
Chamberlin, J.R., and L.T. Kok, 1986. Cabbage lepidopterous pests and their parasites 
in southwestern Virginia. Journal of Economic Entomology.79: 630-632. 
Cisneros, J.D., D. Goulson, L.C., Derwent, D.I. Penagos, O. Hernandez, and T. 
Williams. 2002. Toxic effects of spinosad on predatory insects. Bio. Control. 
23:156-163. 
 95
Cranshaw. W.S. 1984. Effects of a hay mulch and of a companionate planting on 
cabbage pests populations.  The Great Lake Entomologist.  17(1):9-12. 
Eger, J.E., and J.E. Lindenberry. 1998.  Utility of spinosad for insect control in Florida 
Vegetables.  Proceedings of the Fla. State Hort. Soc. 111:55-57. 
Elsey, K.D., and R.L. Rabb. 1970. Analysis of the seasonal mortality of the cabbage 
looper in North Carolina. Ann. Entomol Soc of America. 63: 1597-1604. 
Estada, U. and J. Ferre. 1994. Binding of insecticidal crystal proteins of Bacillus 
thuringiensis to the midgut brush border of the Cabbage Looper, Trichoplusia ni 
(Hubner) (Lepidoptera: Noctuidae) and the selection for resistance to one of the 
crystal proteins. App.Environ. and Microbial. 60: 3840-3846. 
Evenden, M.L., and J.R. McLaughlin. 2004a. Initial development of an attracticide 
formulation against the Oriental fruit moth, Grapholita molesta (Lepidoptera: 
Tortricidae). Environ. Entomol. 33: 213-220. 
Evenden, M.L., and J.R. McLaughlin. 2004b. Factors influencing the effectiveness of 
an attracticide formulation against the Oriental fruit moth, Grapholita molesta. 
Entomol. Exp. Appl. 112: 89-97. 
Evenden, M.L., and J.R. McLaughlin. 2005. Male Oriental fruit moth response to a 
combined pheromone-based attracticide formulation targeting both Oriental fruit 
moth and codling moth (Lepidoptera: Tortricidae). J. Econ. Entomol. 98: 317-
325. 
Evenden, M.L., J.R. McLaughlin, and D. Czokajlo. 2005. Effects of exposure to 
pheromone and insecticide constituents of an attracticide formulation on 
 96
reproductive behavior of Oriental fruit moth (Lepidoptera: Tortricidae). J. Econ. 
Entomol. 98: 334-341. 
Farka, S.R., H.H. Shorey, and L.K. Gaston. 1974. Sex pheromones of Lepidoptera. 
The use of widely separated evaporatores of looplure for the disruption of 
pheromone communication in Trichoplusia ni. Environ. Entomol. 3: 876-877.  
Ferre J, and J. van Rie. 2002. Biochemistry and genetics on insect resistance to Bacillus 
thuringiensis. A review of Entomology. 47: 501-533. 
Furlong, M.J., S. Zu-Hua, L. Yin-Quan, G. Shi-Jian, L. Yao-bin, L. Shu-sheng, M.P. 
Zalucki. 2004. Experimental Analysis of the Influence of Pest Management 
Practice on the Efficay of an Endemic Arthropod Natural Enemy Complex of the 
Diamondback Moth. Journal of Economic Entomology. 97(6): 1814-1827. 
Gaston, L.K., H.H. Shorey, and C.A. Saario. 1967. Insect population control by the use 
of sex pheromones to inhibit orientation between the sexes.  Nature (Lond.) 213: 
1155. 
Greene, G.L., W.G. Genung, R.B. Workman, and E.G. Kelsheimer. 1969. Cabbage 
looper control in Florida- a cooperative program. J. Econ. Entomol. 62: 798-800. 
Godin, C. and Boivin G. 1998. Lepidopterous pests of Brassica crops and their 
parasitoids in southwestern Quebec. J Environ Entomol. 27:1157-1165. 
Guy, R.H., N.C. Leppa, J.R. Rye, C.W. Green, S.L. Barrette and K.A. Hollien. 1985. 
Trichoplusia ni. Handbook of insect rearing, Vol. II. Eds. P. Singh and R.F. 
Moore. 487-494. Elsevier, New York. 
Harcourt, D.G., R.H. Backs, and L.M. Cass. 1955. Abundance and relative importance 
of caterpillars attacking cabbage in eastern Onterio. Canadian Ent. 87: 400-406. 
 97
Harding, J.A., 1976. Seasonal occurrence, hosts, parasitism, and parasites of cabbage 
and soybean loopers in the Rio Grande Valley. Environ Entomol 5: 672-674. 
Harvey, C.T. and M.D. Eubanks. 2004. Effect of habitat complexity on biological 
control by the red imported fire ant (Hymenoptera; Formicidae) in collards. Bio 
Control 29:348-358. 
Harvey, C.T. and M.D. Eubanks. 2004. Intraguild predation of parasitoids by 
Solenopsis invicta: a non-disruptive interaction. Entom. Exp. Et App 114:127-
135. 
Haynes, K.F., W.G. Li, and T.C. Baker. 1986. Control of pink bollworm moth 
(Lepidoptera:Gelechiidae) with insecticides and pheromones (attracticide): lethal 
and sublethal effects. J. Econ. Entomol. 79: 1466-1471. 
Hill, T.A. and R.E. Foster. 2000. Effect of insecticides on the diamondback moth 
(Lepidoptera: Plutellidae) and its parasitoid, Diadegma insulare (Hymenoptera: 
Ichneumonidae). J. Econ. Entomol. 93: 763-768. 
Hines, R.L. and W.D. Hutchinon. 2001a. Evaluation of Action Thresholds and 
Spinosad for Lepidopteran Pest Management in Minnesota cabbage. J. Econ. 
Entomol. 94:190-196. 
Hines, R.L. and Hutchinson, W.D. 2001b, Flea Beetles. University of Minnesota 
Extension Service.  http://vegedge.wmn.edu/vegpest/colecrop/flea.htm. 
Hofer, D., and M.Angst. 1995. Control of pink bollworm in cotton with Sirene, a novel 
sprayable attract and kill formulation. Report of 1995 Beltwide Cotton 
Conferences in San Antonio, TX. 
 98
Janmaat, A.F., J. Myers. 2003. Rapid evolution and the cost of resistance to Bacillus 
thuringiensis in greenhouse populations of cabbage loopers Trichoplusia ni.  
Proceedings of the Royal Society of London. 270: 2263-2270. 
Kemble, J.  1999.  Guid to Commerical Cabbage Production.  Auburn University 
Extension Service.  http://wwww.aces.edu. 
Kok, L.T., and T.J. McAvoy, 1989. Fall broccoli pests and their parasites in Virginia. J 
Econ Sci. 24:258-265. 
Krupke C.H., B.D, Roitberg, G.R.J. Judd, 2000. Field and Laboratory Responses of 
Male Codling Moth to a Pheromone-Based Attract-and-Kill Strategy. . Environ. 
Entomol. 31: 189-197. 
Lamb, R.J., 1989. Entomology of oilseed brassica crops. Annual Review of 
Entomology. 34. 211-219. 
Latheef, M.A., and R.D. Irwin. 1983. Seasonal abundance and parasitism of 
lepidopterous larvae on Brassica greens in Virginia. J Georgia Entomol Soc. 
18:164-168.  
Lasota J.A. and L.T. Kok. 1986. Diadegma insulare (Hymenoptera: Ichneumonidae) 
parasitism of the diamondback moth (Lepidoptera: Plutellidae) in south Virginia, 
U.S.A. J. Entomol Sci. 21: 237-242. 
Leibee, G.L., R.K. Jansson, G. Nuessley, and J.L. Taylor. 1995.  Efficacy of 
emamectin benzoate and Bacillus thuringiensis at controlling diamondback moth 
(Lepidoptera: Plutellidae) populations on cabbage in Florida.  Florida 
Entomol.78(1): 82-96. 
 99
Legaspi B.C. Jr., T.X.Liu, A.N. Sparks Jr. 2000. Occurrence of the diamondback moth 
and its parasitoids in the Lower Rio Grande Valley of Texas. Subtropical Plant 
Science. 21: 237-242. 
Liu, N.N. and X. Yue.2000. Insecticide resistance and cross-resistance in the house fly 
(Diptera: Muscidae). J. Econ. Entomol. 93:1269-1275. 
Liu, T-X, A.N. Sparks Jr., W. Chen, G-M. Liang, and C. Brister. 2002. Toxicity, 
persistence and efficacy of indoxacarb on cabbage looper (Lepidoptera: 
Noctuidae) on cabbage. J.  Econ. Entomol. 92(2): 360-367. 
Liu, T.-X., A.N. Sparks Jr., W.H. Hendrix, and B.S. Yue. 1999. Effects of SpinTor on 
cabbage looper (Lepidoptera: Noctuidae): toxicity and persistence of leaf residue 
on cabbage under field and laboratory conditions. J. Econ. Entomol. 92(6): 1266-
1273. 
Liu, T.-X., A.N. Sparks Jr. 1999. Efficacies of some selected insecticides on cabbage 
looper and diamondback moth on cabbage in South Texas. Subtropical Plant Sci. 
51: 54-58. 
Losel, P.M., G. Penners, R.P.J. Potting, D. Ebbinghaus, A. Elbert, and J. 
Scherkenbeck. 2000.  Laboratory and field experiments towards the development 
of an attract and kill strategy for the control of the codling moth, Cydia 
pomonella. Entomol. Exp. Appl. 99: 39-46. 
Mahr, S.E., D.L. Mahr, J.A. Wyman. 1993. Biological Control of insect pests of 
cabbage and other crucifers in North Central Regional Publication 471. University 
of Wisconsin, Madison, WI. 17-33. 
 100
Maltais, P.M., J.R. Nuckle, P.V. LeBlanc, 1994. Economic threshold for management 
of lepidopterous larvae on broccoli in southeastern New Brunswick. 
Entomological Society of America Horticultural Entomology.  87(3) 766-774. 
McEwen, F.L., G.E.R. Hervey, 1960. Mass-rearing the cabbage looper, Trichoplusia ni, 
with notes on its biology in the laboratory. Annals of the Entomol. Soc. of 
America 53:229-234. 
Mitchell, E.R. 2002. Promising new technology for managing diamondback moth 
(Lepidoptera: Plutellidae) in cabbage with pheromone. J. Environ. Sci. Health 
B37: 277-290. 
Mitchell, E.R., G.Y. Hu, and J.S. Okine. 1997. Diamondback moth (Lepidoptera: 
Plutellidae) infestation and parasitism by Diadegma insulare (Hymenoptera: 
Ichneumonidae) in collards and adjacent cabbage fields. Florida Entomologist. 
80: 54-62. 
Morisak,D.J., D.E. Simonet, and R.K., Lindquist. 1984. Use of action thresholds for 
management of lepidopterous larval pests of fresh-market cabbage. J. Econ. 
Entomol. 77:476-482. 
Mullan, J. M. 2003. Characterization and application of semiochemical-based attract-
and-kill to suppress cabbage looper, Trichopulsia ni (H?bner) in commercial 
vegetable greenhouses. Master Thesis, Simon Fraser University, British 
Columbia, Canada. 
National Agricultural Stastics Service (NASS). 2004.  http://www.usda.gov/nass/. 
Oatman, E.R. and G.R. Platner. 1969. An ecological study of insect populations on 
cabbage in southern California. Hilgardia. 40:1-40. 
 101
Parker, R.E. 1979. Introductory statistics for biology, 2
nd
 ed. Cambridge University 
Press, Cambridge, UK. 
Pimental, D. 1961. Natural control of caterpillar populations on cole crops. J Econ 
Entomol. 54: 889-892. 
Reddy,G.V.P., and A. Guerro. 2001. Optimum timing of insecticide applications 
against diamondback moth, Plutella xylostella, in cole crops using threshold 
catches in sex pheromone traps. Pest Management Science. 57:90-94. 
Ronald, T. 1997. Relationship between the number of males captured by sex pheromone 
traps and wild population density in the field.  Journal of Entomology Sciences. 
22. 120-137. 
Ru, N. and R.B. Workman. 1979. Seasonal abundance and parasites of the imported 
cabbageworm, diamondback moth, and cabbage webworm in northeast Florida. 
Florida Entomol. 62: 68-69. 
Rueda, A, and A.M. Shelton. 1995. Diamondback moth (DBM). Global Crop Pests, 
Cornell International Institute for Food, Agriculture and Development. 
Sarnthony, O. Keinmeesuke, P. Sinchaisri, N., abd Nakasuji, F. 1989. Development 
and reproductive rate of the diamondback moth, Plutella xylostella, from 
Thailand.  Applied entomology and zoology. 24, 202-208. 
SAS Institute. 1998. JMP Statistics and Graphics Guide, Version 5.1. SAS Institute, 
Cary, NC, USA. 
Sayyed, A.H., D. Omar, D.J. Wright. 2004. Genetics of spinosad resistance in a multi-
selected population of Plutella xylostella. Pest Management Science. 60:827-832. 
 102
Schellhorn, N.A. and V.L. Sork. 1997. The impact of weed diversity on insect 
population dynamics and crop yield in collards, Brassica oleraceae 
(Brassicaeceae). Oecologia 111: 233-240. 
Schellhorn, N.A., G. Sienkmann, C. Paull, G. Furness, G. Baker, 2004. The use of 
dyes to mark populations of beneficial insects in the field. International Journal of 
Pest Management. 50(3): 153-159. 
Shelton, A.M., and Collins, H.L. 2000.  Techniques for rearing Plutella xylostella at 
N.Y.S. Agricultural Experiment Station Geneva, New York. 
Shelton, A.M., J.T. Andaloro, and J. Barnard. 1982. Effects of cabbage looper, 
imported cabbageworm, and diamondback moth on fresh market and processing 
cabbage. J. of Econ. Entomol. 75. 742-745. 
Shelton, A.M., M.K. Sears, J.A. Wyman, and T.C. Quick. 1983. Comparision of 
action thresholds for lepidopterous larvae on fresh-market cabbage. J. of Econ. 
Entomol. 76: 196-199. 
Shelton, A.M., J.A. Wyman, N.L. Cushing, K. Applebeck, T.J. Dennehy, S.E. Mahr, 
and S.E. Eigenbrode. 1993. Insecticide resistance of diamondback moth in North 
America. J. Econ. Entomol. 86: 11-19. 
Shi-Jian, G., G. Geitz, T. Franklin, L. Yin-Quan,  M.J. Furlong, M. P. Zalucki, L. 
Cooper, 2004. A comparision of the performance and biological efficency of new 
knapsack sprayers and a controlled droplet application (CDA) sprayer for the 
control of the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae). 
International Journal of Pest Management. 50(2): 121-127. 
 103
Shirai Y. and A. Kukanura 1995. Relationship between the numbers of wild males 
captured by sex pheromone trap and the population density estimated from a 
mark-recapture study in the Diamondback moth, Plutella xylostella, (L.) 
(Lepidoptera: Plutellidae). Applied Entomology and Zoology. 30: 543-549. 
Sorenson, K.A.  and Baker, J.R. 1983.  Insects and Related Pests of Vegetables, Some 
Important Common and Potential Pests in the Southeastern United States.  The North 
Carolina Agricultural Extension Service, Raleigh.   
Stern, V.M., R.F. Smith, R. van den Bosch, and K.S. Hagen. 1959. The integrated 
control concept. Hilgardia. 29:81-101. 
Suckling, D.M. and E.G. Brockerhoff. 1999. Control of lightbrown apple moth 
(Lepidoptera: Tortricidae) by using an attracticide. J. Econ. Entomol. 92:367-372. 
Suenaga, H. and T. Hamamura. 2001. Occurrence of carabid beetles (Coleoptera: 
Carabidae) in cabbage fields and their possible impact on lepidopteran pests. The 
Journal of Applied Entomology and Zoology.  36(1): 151-160. 
Suenaga, H. and T. Hamamura. 1998. Laboratory evaluation of carabid beetles 
(Coleoptera:Carabidae) as predators of diamondback moth (Lepidoptera: 
Plutellidae) larvae. Environmental Entomology 27: 767-772. 
Tabashink, B.E. 1994. Evolution of resistance to Bacillus thuringiensis Annual Review 
of Entomol. 39: 47-49. 
Tabashink, B.E., Y.B. Liu, T. Malyar, D.G. Heckel, L. Masson, V. Ballester, F. 
Gradero, J.L., Menusa, and J. Ferre. 1997. Global variation in the genetic and 
biochemical basis of diamondback moth resistance to Bacillus thuringiensis. 
Proceedings of the National Academy of Sci. 94 (24): 12780-12785. 
 104
Talekar N.S. and A. M Shelton. 1993. Biology, ecology, and management of the 
diamondback moth.  Annual Review of Entomol. 39: 275-301. 
Tang, J.D., S. Gilboa, R.T. Roush, and A.M. Shelton. 1997. Inheritance, stability, and 
lack-of-fitness costs of field-resistance to Bacillus thuringiensis in diamondback 
moth (Lepidoptera: Plutellidae) from Florida. J. Econ. Entomol. 90: 732-741. 
Tamaki, Y., K., Kawasaki, H. Tamada, T. Kashihara, N. Osaki, T. Ando, S. 
Yashida, H, Kakinohama. 1977. Z-11 hexadecenal and Z-11 hexadecenal 
acetate: sex pheromone components of the diamondback moth (Lepidoptera: 
Plutellidae). Appl. Entomol. Zoo. 12: 208-210. 
Wagener B., A. Reineke, B. L?hr, and C.P.W. Zebitz. 2004. A PCR-based approach to 
distinguish important Diadegma species (Hymenoptera:Ichneumonidae) 
associated with diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae). 
Bulletin of Entomological Research.  94: 465-471. 
Wang, X.P. V.T. Le, Y.L. Fang, Z.N. Zhang. 2004. Trap effect on the capture of 
Plutella xylostella (Lepidoptera: Plutellidae) with sex pheromone lures in cabbage 
fields in Vietnam. 39(2): 303-309. 
Wei, X.P., A.G. Appel, W.J. Moar, and N.N. Liu. 2001. Pyrethroid resistance and 
cross-resistance in the German Cockroach, Blatella germanica (L.). Pest 
Management Sci. 57: 1055-1059. 
Williams, L., and J. Dangler. 1992. 1992 Budgets for vegetable crop enterprises in 
Alabama.  Special Extension Report, Alabama Cooperative Extension Service, 
AECBUD 1-4. 
 105
Xu, T.X. Liu, G.L.Leibee, W.A. Jones, 2004. Effects of Selected Insecticides on 
Diadegma insulare (Hymenoptera: Ichneumonidae) a Parasitoid of Plutella 
xylostella (Lepidoptera: Plutellidae). Biocontrol Science and Technology.  
14(7):713-723. 
Wagener B., A. Reineke, B. L?hr, and C.P.W. Zebitz. 2004. A PCR-based approach to 
distinguish important Diadegma species (Hymenoptera:Ichneumonidae) 
associated with diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae). 
Bulletin of Entomological Research.  94: 465-471. 
Zhao, H.L. and M.S. You. 2001. Advances in research on the insecticide resistance of 
the diamondback moth Plutella xylostella (L.) and its management. 
Entomological Journal of East China 10:82-88.