STUDIES ON THE INSECTICIDE RESISTANCE AND SYNERGISM IN ORGANOPHOSPHORUS-RESISTANT GREEN LEAFHOPPER NEPHOTETTIX CINCTICEPS
CHEN CHIAO-YUN CHIANG CHIA-LIANG LIN HAO TSOU BAI-SHIANG TANG CHEN-HUA(Shanghai Institute of Entomology, Academic Sinica)
By combining bioassay technique with enzymatic determination in vitro, the mechanisms of resistance and synergism to some insecticides in organopbosphorus-resis-tant green leafhoppers have been studied. The results are briefly stated as follows:(1)The increase of carboxylesterase activity may be the cause of resistance of the green leafhopper against Malathion.(2)Carbozylesterase plays a more important role in the resistance of the green leafhopper against Dimethoate than the mixed function oxidase (mfo).(3)The fungicide Kitazin strongly synergizes the toxicity of Malathion and Dimethoate against the resistant green leafhopper and the degree of its synergistic action is similar to that of TPP. The enzymatic study shows that Kitazin strongly inhibits carboxylesterase in vitro. Thus the synergism of Kitazin might be due to its highly effective inhibition to carboxylesterase.