.0.2% Bitter Skin Vine Prime Ec Resistance Preliminary Study

0.2% Celangulin EC is a new kind of botanical insecticide. It is essential to study the resistance of 0.2% Celangulin EC for sake of guiding to be used in the field. The preliminary studies to Celangulin resistance on the trend of resistance development, cross-resistance and mechanism of resistance were carried. The selective strain is the susceptible strain of diamondback moth. The main results are as follows:After 20 generations selection, the resistance of moth increased by 21.57 folds. The speed of resistance was slower than chemical and microbial insecticides, such as Bt and avermectin. The time course of resistance development appeared to be "S" shape. The resistance development was slow in the earlier stage(F0～F6), faster in the mid-stage(F6～F17),and stable in the later stage(F17～F20). There was no obvious difference between the susceptible(F0) and the selective strain(F5, F10, F15 and F20) in biological characteristics, which shows 0.2% Celangulin EC can't result in degeneration of the strain.The sensitivities of the Celangulin-resistance strain to 10 insecticides were tested. The results showed the resistant strain has positive cross-resistance to dimehypo, cartap and isoprocarb(4.63, 4.11 and 3.71 folds), and negative cross-resistance to deltamethrin, cypermethrin, permecthrin and Bt(0.22, 0.26, 0.01 and 0.66 folds). The sensitivities of cartap, dimehypo and deltamethrin-resistance strains to 0.2% Celangulin EC showed the strains has 1.06, 1.76 and 3.61 folds resistance to 0.2% Celangulin EC, respectively. PAGE demonstrated that the resistance of 0.2% Celangulin EC was related to special esterases. Maybe enzymes 4～5 are special esterases of susceptible strain and enzyme 10 is special esterase of the resistance strain. Enzyme 10 is an important detoxicative enzyme. Maybe the gene amplification is not a reason of resistance development, but the genes of coding enzymes 4～5 altered expression or changed structure, so that enzyme 10 was expressed. The gene of coding enzyme 10 concerns resistance, probably. The result of study on activities of phosphatase and carboxylesterase showed the resistance wasn't related to phosphatase and carboxylesterase.