Susceptibilities of the cabage aphid, Brevicoryne brassicae (Linnaeus) to selected organophosporous insecticides

Abstract : In this study the effect of three insecticides including Trichlorophen, chlorpyriphos-methyl and Oxydemton-methyl on Brevicoryne brassicae in a leaf dip assay was investigated. At the highest and the lowest concentrations of Oxydemton-methyl 91.16 and 25 % mortality was achieved, respectively. Fifty percent mortality (LC50) was recorded at 19.62 ppm with fudicial limit of 11.41 and 30.73 ppm. Also, LC10 and LC90 were estimated to be 1.08 and 356.27 ppm. When different concentrations of Trichlorophen was used at the lowest and the highest concentrations about 21.27 and 87.23 % mortality was achieved, respectively which correspond to 30 and 480 ppm of the insecticide doses. Lethal concentration of 10, 50 and 90% was calculated using probit analysis and estimated LC10, LC50 and LC90 were 14.30, 95.96 and 643.89 ppms, respectively. Estimated lethal concentration of 10, 50 and 90 for chlorpyriphos-methyl were equal to 14.06, 59.65 and 253.10 ppm, respectively. Results showed that the most effective insecticide was Oxydemton-methyl with the LC50 value of 19.62 ppm followed by chlorpyriphos methyl with the LC50 value of 59.65 ppm and Trichlorophen with the LC50 value of 95.96 ppm. Therefore, Oxydemton-methyl act on insect through contact and systemic action that is major reason why this insecticide has low LC50 and is more effective than the other two insecticides which are contact and stomach insecticides
Keyword : Cabbage aphid, Oxydemton-methyl, Chlorpyriphos methyl, Trichlorophen
Author(s) : , A. Moslemi, S. Ravan, B. Mehrabi, A. R. Bandani
Downloads : 2123

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