Efficacy of neem seed oil in controlling bollworms, leafhoppers and aphids
1987
Solsoloy, A.D. | Solsoloy, T.S.
Treating cotton bolls with 2% neem seed oil emulsified with 1% surfactant inhibited the feeding of even starved bollworm larvae. The amount of frass they excreted was significantly lower than the control which was sprayed with acetone. Similarly, the larvae were relatively lighter and smaller. These results showed the antifeedant effect of the oil. The crude 2% oil with 1% surfactant had a strong ovicidal effect on bollworm eggs. It controlled egg hatching by 78% relative to the control. Field evaluation of the efficacy of 5% neem seed oil sprayed on infested cotton plants showed a comparable effect with the check insectic1643ide during early (50 DAE) and late (118 DAE), but no control during peak (86 DAE) bollworm populations. Leafhoppers and aphids were not adequately controlled by the extract when compared with the check insecticides, Metasystox R and Selecron 500, respectively. Leafhopper control was observed only at low infestations, but a relatively lower rate of efficacy than check insecticide. Aphids were not at all controlled. The ineffectivity of the oil extract on leafhoppers and aphids and apparent effectivity on bollworms could be due to their differences in the mode of feed
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