Sub-lethal effects of tiametoxam on life table parameters of the cabbage aphid, Brevicoryne brassicae (L.) (Hemiptera: Aphididae) under laboratory conditions.

摘要

Efficiency of tiametoxam was determined on population growth parameters of cabbage aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae) using demographic toxicology by leaf spray method. At first, bioassay was performed. The LC₅₀ values and confidence limits for thiamethoxam were 169.05 ppm (92.61-342.51). To evaluate, the sub-lethal effect of this insecticide on population growth parameters of cabbage aphid, LC₂₅ and LC₁₀ concentrations of tiametoxam were used at 58.8 and 22.05 ppm, respectively. Also, the LC₅₀ value of insecticide on the life table estimates was measured. Experiments were carried out in the laboratory at 23+or-1 degrees C, 60+or-5% RH and 16:8 (L:D) photoperiod on cabbage seedlings, Brassica oleracea, var. capitata L. Net fecundity rate decreased in insecticide-treated populations. Intrinsic rates of increase (r_m) were lower in tiametoxam treatment than in controls. There was a relative increase in intrinsic death rates of treated populations. The mean generation time and doubling time were also lower in population treated with insecticide than the control. There was a considerable reduction in the average numbers of nymphs reproduced per female as compared with the control. The average longevity of female adults in the control was significantly different (p<0.05) from those treated with thiamethoxam.