Laboratory Effects of Two Organically-Certified Insecticides on Trichopoda pennipes (Diptera: Tachinidae)

The objective of this laboratory study was to determine the effects of two organically-certified insecticides, azadirachtin and spinosad, on the stink bug parasitoid Trichopoda pennipes (F.) (Diptera: Tachinidae) in residual, topical, and oral toxicity tests. The insecticide lambda-cyhalothrin was used as a conventional crop production standard for control of lepidopterous pests. Azadirachtin was the only insecticide in which T. pennipes adults survived after exposure to dried residues, topical applications, and insecticide-treated food. Spinosad was as highly toxic to this parasitoid as lambda-cyhalothrin in all 3 tests even though spinosad was slower acting than lambda-cyhalothrin. These results suggest that azadirachtin would probably be safer to T. pennipes adults than spinosad in organically-grown crops.