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Response of Ootheca bennigseni (Coleoptera: Chrysomelidae) to extracts from neem
- Karel, A.K.
- Journal of economic entomology 1989 v.82 no.6 pp. 1799-1803
- Phaseolus vulgaris, crop damage, Coleoptera, dimethoate, insect control, neem seed extract, Azadirachta indica, Tanzania
- Various formulations of neem (Azadirachta indica A. Juss) extract were evaluated under field and greenhouse conditions to examine the effects of foliar beetle, Ootheca bennigseni Weise, a serious pest of beans and other legumes in many parts of Africa. At concentrations of 2.0 and 4.0%, neem formulations from seed kernels deterred O. bennigseni from feeding bean leaves. None of the neem formulations protected bean plots completely. However, formulations of neem seed kernel extract resulted in lower foliar damage and less incidence of O. bennigseni than other formulations. In most instances, untreated leaves were severely damaged, whereas leaves protected with neem extracts were not attacked or were only slightly damaged. Residual effectiveness of various neem extracts varied considerably; residual activity was shorter with lower concentrations. In greenhouse studies, 1.0% aqueous leaf and seed kernel extracts were highly active as an antifeedant against O. bennigseni, which consumed little or none of the leaves. In free-choice experiments, bean seedlings treated with 1.0 and 2.0% neem seed kernel extracts were well protected. Because of their effectiveness, safety for the environment, lower cost, availability, and easy preparation, neem extracts have great potential in protecting beans against foliar beetles on beans.