Studies On The Spatial And Temporal Dynamics Of Insecticide Resistance And Its Biochemical Mechanism In Lipaphis Erysimi Kaltenbach

Lipaphis erysimi Kaltenbach, which belongs to Homoptera, is an important worldwide pest to eruciferous vegetables. Serious damage to cruciferous vegetables such as cabbage (Brassica oleracea van capitata), cauliflower (Brassica oleracea var. botrytis) and greengrocery were found in vegetables fields in Fuzhou, Fujian, China. Vegetable production therefore is seriously threatened. To provide theoretical basis for L. erysimi integrated control, studies on the dynamics of resistance development and seasonal variations of insecticide resistance to methamidophos, cypermethrin, fenvalerate, imidacloprid, avermectins, carbosulfan and chlorpyrifos, the dynamics of CarE and the frequency distribution of individual L. erysimi CarE activity of several different Lipaphis erysimi Kaltenbach populations in Fuzhou, and the relationship between seasonal variation of Lipaphis erysimi Kaltenbach populations and their insecticide resistance were conducted. The results are summarized as follows:1. Compared to the susceptible population which was reared in the the field insecticide-free condition, the insecticide ratios to the insecticides in Jianxin L. erysimi population were 54.1-, 130.0-, 121.5-, 20.0-, 27.1-, 9.7-, and 42.3-fold respectively; the insecticide ratios to the insecticides in Shangjie L. erysimi population were 56.5-, 113.5-, 93.4-, 21.4-, 26.3-, 7.0-, and 46.6-fold respectively; the insecticide ratios to the insecticides in Hongtang L. erysimi population were 60.0-, 112.0-, 111.1-, 19.6-, 26.2-, 10.6-, and 43.0-fold respectively; and the insecticide ratios to the insecticides in Nongda L. erysimi population were 61.4-, 145.3-, 133.8-, 25.4-, 21.4-, 10.3-, and 45.8-fold respectively. L. erysimi showed very high resistance levels to methamidophos, cypermethrin and fenvalerate, these insecticides thus should be not used any longer; while the resistance levels to imidacloprid, avermectins, carbosulfan and chlorpyrifos were moderate, and these insecticides should be used restrainedly.2. In addition, L. erysimi populations showed seasonal variations of resistance to the insecticides. Generally to say, insecticide resistance in early summer and autumn is higher than that in spring and winter in one year. Therefore L. erysimi integrated control should according to its resistance seasonal variation.3. Studies on frequency distribution of individual L. erysimi CarE activity indicated that the frequency distribution of individual L. erysimi CarE activity both of resistant populations and of susceptive population were trend to normal school, and the resistant L. erysimi populations have significant higher CarE activity than susceptive L. erysimi population. Thereinto, the activity level of CartE in Hongtang L. erysimi population is the highest among the four field populations, which is tally to the result of drug-fast test on each population.