The effect of azadirachtin on larvae of the European corn borer, Ostrinia nubilalis
1986
Meisner, J. (The Volcani Center, Bet Dagan (Israel). Dept. of Toxicology and Entomology) | Melamed-Madjar, V. | Tam, S. | Ascher, K.R.S.
德语. Methanolic solutions of azadirachtin were sprayed at different concentrations on sweet corn seedlings and the fresh deposits were assayed against 2-3 mg larvae of Ostrinia nubilalis. Larval survival, larval weight and percent of pupation and adult emergence served as the criteria af azadirachtin activity. At all concentrations tested, there was a significant difference in larval weight between treatments and the untreated controls. Only 27 per cent of the larvae pupated at 0.005 per cent, whereas in the controls the pupation rate ranged between 50 and 60 per cent, practically no pupation occurred at 0.006-0.05 per cent. The residual effect of 0.025 per cent azadirachtin was investigated 2, 4 and 6 days after treatment. Larval weight on treated seedlings was significantly lower than on untreated ones. No pupae developed from larvae fed on treated seedlings 2 days after treatment, and of those fed on seedlings with 4- and 6-day-old residues, only 11 per cent and 16 per cent, respectively, pupated
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