Monitoring On Pesticide Resistance And Its Mechanisms In Panonychus Citri McGregor

The susceptibility and the activities of several enzymes of Panonychus citri in different districts around Chongqing were investigated, respectively. Influence of the citrus germplasm on the enzymes activity and propargite susceptibility of P. citri were also studied. Furthermore, the changes of the sensitivity to acaricides and enzyme activity after the treatment with different acaricides were monitored. After over one year's study, the main research results are summarized as follows:1. Monitoring on acaricides resistance of Panonychus citri in different districts1.1 Susceptibility monitoring of P. citri in different districtsThe acaricides susceptibility of Panonychus citri collected from the citrus orchards in Changshou, Wanzhou, Beibei, Nanchong and Anyue were investigated, respectively. As for propargite, the LD50 of Changshou population was the highest and it was 2.82-fold compared with Anyue population with the lowest LD₅₀ among five populations; for amitraz, the LD₅₀ of Wanzhou population was the highest and it was 15.03-fold compared with Changshou population with the lowest LD50 among five populations; for azocyclotin, the LD₅₀ of Beibei population was the highest and it was 25.35-fold compared with Changshou population with the lowest LD₅₀ among five populations; for diafenthiuron, the LD₅₀ of Nanchong population was the highest and it was 15.25-fold compared with Beibei population with the lowest LD₅₀ among five populations. The results above showed that the various application levels of acaricides contributed to sensitivity difference of P.citri among different districts.1.2 Enzyme activity of P. citri in different districtsBiochemical assay showed that the tested enzyme activity of P. citri in different districts were also different. The activities of AChE, ACP and GSTs were the highest in Anyue population; while the activities of ALP, SOD, POD and CAT were the highest in Changshou population; the activity of CarE was the highest in Beibei population. The statistical analysis revealed that only AChE and CarE activities were different significantly among different districts.2. Influence of citruses germplasm on the enzyme activity and...