Development of resistance in field strain of Aphis craccivora to the dinotefuran insecticides from the new class neonicotinoids and its effect on some enzymes content.

Resistance of cowpea aphid colony to the newest insecticide, dinotefuran was tested by selection pressure for 20 generations. Resistance ratio reached 148.8 fold in relation to susceptible strain. The LC50 value of the parent (first generation) was 5.39 ppm with slope value 1.06 ±0.53 which mean that this strain was not homogenous to this insecticide. The value of LC50 increased slowly with selection pressure, reached 22.24 ppm for the 10 th generation. Up to 15 th generation with the same selection pressure LC50 value increased to reach to 66.19 ppm and reached to 230.71 ppm in case of 20 th generation. Resistance ratio values in relation to susceptible strain, increased until the 10 th generation to 14.34 fold, and fastly increasing to 42.7 fold and 148.8 fold to 15 th and 20 th generation respectively. Selection pressure produced some differences in total protein content and SDSprotein patterns. The analysis of esterase patterns obtained by the native- PAGE and by using α naphthyl acetate as a substrate which revealed a minor was measured.