Combined application of neem-seed-kernel-extract with Bacillus thuringiensis-products for the control of Spodoptera frugiperda and Aedes togoi
1986
Hellpap, C. (Giessen Univ. (Germany, F.R.). Inst. fuer Phytopathologie und Angewandte Zoologie) | Zebitz, C.P.W.
Four and ten days old larvae of Spodoptera frugiperda were fed in the laboratory for one to three days with leaves of Ricinus communis treated either with a neem-seed-kernel-extract (AZT-VR), Bacillus thuringiensis (Dipel), or a mixture of both. AZT-VR was tested in concentrations of 25 ppm, to 250 ppm, the concentrations of Dipel were 0.1 per cent and 0.5 per cent. Young fourth instar larvae and fourth instar larvae of different age of Aedes togoi were held in water treated with a neem-seed-kernel-extract (AZT-VR-K), Bacillus thuringiensis var. israelensis (Teknar), or a mixture of both until adult emergence. The combination of neem-seed-kernel extract and B. thuringiensis-products increased mortality compared to that exerted by each compound alone. Furthermore the combination decreased pupal weight of surviving test insects and reduced the time required to kill 50 per cent of the larvae of S. frugiperda. In the tests with A. togoi the dead larvae/dead pupae ratio was shifted to a higher number of killed pupae in the combinations compared to the ratios revealed after application of the compounds alone. In most of the combinations the resultant effect of the two substances was the same as the value expected on the basis of the part-actions, that is an additive action. In some combinations however, the resultant effect was larger as expected and showed a synergistic action
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