EFFECTS OF NOVEL PESTICIDES ON TRICHOGRAMMA PRETIOSUM

摘要

The effects of several pesticides on the foraging behavior and life history of Trichogramma pretiosum were evaluated. Thepesticides tested were: (1) Tracer~R (spinosad; Dow AgrosSciences); (2) Steward~R (indoxacarb; DuPont); (3) Dimilin~R(diflubenzuron; Uniroyal); and (4) Karate Z~R (l-cyhalothrin; Syngenta). For the foraging study, eggs were treated with a singlerate of each compound, the eggs were allowed to dry, and female parasitoids were each allowed to forage on two eggs. Fourbehaviors (antennating, stinging, host feeding, and cleaning) were timed and compared among treatments. For the life historystudy, eggs parasitized 3 days prior were treated with 2 rates of each of the compounds, and the developmental times, emergencerates, parasitoid size (right hind tibia length), female longevity, and fecundity were assessed. Female parasitoids spentsignificantly less time foraging on both eggs treated with Karate than on eggs treated with Steward and Tracer, where femalesspent the greatest amount of time. Most of this difference was due to shortened stinging and prolonged cleaning times forfemales on the Karate-treated eggs, and prolonged stinging times and cleaning times for females on the Steward- and Tracertreatedeggs, respectively. Pesticide treatment significantly affected preimaginal developmental times, but these differences weresmall and likely of limited biological significance. Parasitoid emergence was adversely affected by Tracer and Karate at bothrates, and by Dimilin at the high rate (0.125 lbs AI/A). Females emerging from eggs treated with a low rate of Karate (0.015lbs AI/A) were significantly larger than females emerging from eggs treated with Dimilin at the low rate (0.03 lbs AI/A) butno other differences were observed in size. Female longevity and offspring production were unaffected by the treatments thefemales had received while developing in the host egg.