An Evaluation of Hemipteran Pests and Cotton in Alabama

Abstract

Hemipterans have been major pests in cotton since the end of the Boll Weevil Eradication Program and the advent of transgenic cotton. The objective of this study is to provide better insights into integrated resistance management strategies in tarnished plant bugs and the addition of a new class of insecticide to help provide residual control of stink bugs in cotton. An evaluation of insecticide resistance to five common insecticides used in cotton on tarnished plant bug was tested in six distinct regions of Alabama. Field collections were made in the non-crop reservoirs daisy fleabane and crimson clover prior to the growing season and a lab colony of tarnished plant bug was obtained from Mississippi State University to serve as a standard to measure insecticide resistance. A glass scintillation vial bioassay was performed using technical grade formulations for acephate, bifenthrin, dicrotophos, imidacloprid, and thiamethoxam. Distinct regions of Alabama were shown to have resistances that were specific to that area with bifenthrin being the most commonly resistant insecticide. We evaluated the effects of the insect growth regulator novaluron in southern green stink bug, Nezara viridula. Sublethal effects on adult fecundity were tested using a bean dip assay. We found no significant effect on egg masses, eggs, or egg hatch rate. Direct mortality was tested using a bean dip assay on second through fifth instar southern green stink bug nymphs. Mortality was significantly greater in second, third and fifth instars and approaching significance in fourth instars. Field trials were conducted using a randomized complete block design; we found no significant differences for mean internal boll damage or mean yield across the three site-years.