Comparative Study of Gravid-Trap Infusions for Capturing Blood-Fed Mosquitoes (Diptera: Culicidae) of the Genera Aedes, Ochlerotatus, and Culex

Abstract

Field experiments were conducted in east-central Alabama to compare the attractiveness of selected gravid-trap infusions to ovipositing female mosquitoes of 3 medically important genera: Aedes, Ochlerotatus and Culex. Evaluations of infusions to collect medically important Culex females were performed in 2003 and 2004. Infusions were produced from Bermuda hay and 3 species of emergent aquatic plants: soft rush, Juncus effuses; a common sedge, Rhynchospora corniculata; and broad-leaf cattail, Typha latifolia, which are typical of Culex larval habitats. Experimental sites included a hardwood bottomland site bordering a marsh in Tuskegee National Forest, Macon County, AL and a soils bioremediation site in Lee County, AL. Carbon dioxide-baited miniature light traps were operated concurrent with gravid traps to monitor activity of various mosquito species at both sites. Gravid traps with hay infusion collected the greatest mean Culex quinquefasciatus and Culex restuans females in 2003 and in 2004. Traps with sedge infusion collected the second greatest mean of females for both species, followed by infusions of cattail and rush. The results indicate that hay infusion is highly attractive to Culex spp., such as Cx. quinquefasciatus and Cx. restuans, and is the infusion of choice for collecting medically important Culex spp. in gravid traps. In 2004 field experiments were conducted to compare the attractiveness of infusions made from commercially available garden products to an oak-leaf infusion standard to container-breeding Aedes and Ochlerotatus females. Three products selected from preliminary experiments (composted horse manure, dyed (red) hardwood mulch, and pine straw) were compared to an oak-leaf infusion under field conditions at 2 sites in Lee County, AL: an Automobile Salvage Yard, Phenix city and a suburban forested lot, Dean Road, Auburn. Container-breeding mosquitoes collected from gravid-traps included females of Ae. albopictus and Oc. triseriatus. Neither of these species demonstrated a preference for any of the infusions evaluated in experiments at either field site. In general, females of Culex spp. demonstrated selectivity when choosing an oviposition site while Aedes and Ochlerotatus females did not. Factors associated with oviposition behavior of the latter 2 genera most likely account for their lack of preference for any single infusion type.