Effects of Neem (Azadirachta indica A. Juss) on Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae), a Parasitoid of Nezara viridula (L.) (Hemiptera: Pentatomidae)

Abstract

The effects of neem (Azadirachtin indica A. Juss) on Trissolcus basalis (Wollaston), an egg parasitoid of Nezara viridula (L.), were assessed in the laboratory and in cowpea (Vigna unguiculata [L.] Walpers). Treatment of N. viridula eggs with 0.5% (225 ppm azadirachtin) aqueous solution of neem had no effect on parasitization by T. basalis, using both choice and no-choice tests. Parasitoid development and emergence from host eggs treated before or after parasitization also were not affected by neem compared with controls. Additionally, neem did not affect longevity of adult parasitoids from treated eggs or the reproductive activity of females compared with controls. In a field choice test using treated and control eggs, parasitism levels were similar. Also, parasitism of eggs was similar in treated and control cowpea plots. These results suggest that neem may be safe to parasitoids of N. viridula and could be an important component of an integrated pest management program in cowpea.