SELECTIVITY OF CERTAIN INSECTICIDES FOR CONTROLLING THE CABBAGE APHID Brevicoryne brassicae (L.) and Their Effect on Some Predatory Insects on CAULIFLOWER FIELDS IN EL-MINIA REGION-UPPER EGYPT

The relative toxicity of thiamethoxam, lambda-cyhalothrin, dimethoit, chlorpyrifos and (lambda- cyhalothrin + chlorpyrifos) were tested against the cabbage aphid, brevicoryne brassicae (l.) on cauliflower in el-minia regon during 2015 season. the population of cabbage aphid on cauliflower plants was nearly the same in all the treat plants before application with insecticides in 2015 season. the population density of cabbage aphid was strongly decreased in all treated plots after 3 days from insecticides application compared with control. the average reduction of all compounds during experiment were 86.8 and 76.1for thiamethoxam and (chlorpyriphos + lambda-cyhalothrin), respectively. also, the results revealed that all compounds differed significantly in their toxicity except lambda-cyhalothrin , dimethoit and chlorpyrifos (no significant difference between for their toxicity, which were 64.3, 66.5 and 62.3 percent reduction, respectively). in general, data showed that superiority of thiamethoxam as systemic insecticides activities than non-systemic insecticides in their toxicity after 3,7 and 15 days. on the other hand, the average reduction of all compounds during experiment to coccinella undeciumpunctata l. were 45, 38.3, 38, 37.3 and 30.7, for (chlorpyriphos + lambda-cyhalothrin), chlorpyriphos , lambda-cyhalothrin, dimethoit and thiamethoxam, respectively. the degree of selectivity to all compounds was selectivity but thiamethoxam was the highest. also, thiamethoxam was good selectivity on scymuns spp. and all compounds were selectivity and the average reduction to all compounds during experiment to scymuns spp were 41.7, 35, 31.4, 31 and 16 percent reduction for ( chlorpyriphos + lambda- cyhalothrin), lambda-cyhalothrin, dimethoit , chlorpyriphos and thiamethoxam, respectively. in general, data showed the tested compounds did not completely eliminate the beneficial arthropods. the superiority of thiamethoxam as systemic insecticides activities than non-systemic.