Efficacy of the plant phototoxinα-terthienyl againstAedes intrudens and effects on nontarget organisms.

The botanical phototoxin, α-terthienyl (α-T) was spray applied to natural or artificial pools containing mosquito (Aedes intrudens) larvae and nontarget invertebrates (caddisfly, damselfly, midge, shrimp,Daphnia, snail) and one vertebrate (trout) at concentrations varying from 0.01 to 1 kg/hectare, under field and laboratory conditions. All field-treated nontarget invertebrates survived α-T treatment better thanA. intrudens which can be controlled at doses as low as 0.01 kg/hectare within one week. Under laboratory conditions, snails and trout survived α-T and UV treatments up to 10 kg/ hectare. These results compare favorably with organophosphates and pyrethroid insecticides currently used for mosquito control. The results confirm that α-T is a highly effective larvicide with acceptable nontarget effects.