Response of Culicoides sonorensis (Diptera : Ceratopogonidae) to 1-octen-3-ol and three plant-derived repellent formulations in the field

The potential attractant 1-octen-3-ol and 3 potential repellents were assay ed for activity for Culicoides sonorensis, the primary vector of bluetongue virus in North America. Collections using octenol were low, but numbers in suction traps were greater in the high-octenol treatment(11.5 mg/h) than i n the low-octenol treatment (1.2 mg/h) or unbaited control for both sexes. Collections using high octenol, CO2 (similar to 1,000 ml/min), or both show ed octenol alone to be significantly less attractive than either of the CO2 treatments and that octenol did not act synergistically with this level of CO2. A plant-derived (Meliaceae) extract with 4.5% of active ingredient (A I) (Ag1000), heptanone solvent, Lice free* (2% Al from plant extracts in wa ter), Mosi-guard with 50% Eucalyptus maculata var. citriodora Hook extract, and N,N-diethyl-m-toluamide (deet) were applied to polyester-cotton coarse mesh nets and deployed in conjunction with suction light traps plus CO2. C ollections in the trap with deer were 66% lower (P < 0.05) than the heptano ne and 56% (P > 0.05) less than the untreated (negative) control Relative t o deet, collections in the traps with the lice repellent, Ag1000, and Mosi- guard were reduced by 15, 34, and 39%, respectively (P > 0.05). The method has promise for field screening of potential repellents before on-animal te sting.