Studies On Investigation Of Pesticides Application And Evaluation Of Pesticides Efficacy On Cnaphalocrocis Medinalis Guenee In Guangxi

In this paper, the investigation of pesticides application on Cnaphalocrocis medinalis Guenee and farmers’ behaviour of using pesticides were researched, followed by the sensibility of different geographical C. medinalis Guenee populations in Guangxi to four pesticides and control effects of8pesticides in Nanning population. These studies set strong foundation for sensibility risk assessment, to lay the basis for scientifically rational using pesticides. The main results were shown as follows:1The results showed that the purchase frequency and sell frequency of avermectin and chlorpyrifos were higher in2012, Guangxi. The educational levels of farmer were low and their ages were higher. When they purchased pesticides, they consider control effect and price of pesticide first.2The results of toxicity test demonstrated that in2012, Guangxi, the sensibility of different geographical populations existed difference. The order of sensibility to chlorantraniliprole was Hengxian,Laibin, Yongfu, Fangcheng, Baise, Nanning, Xing’an, Hepu, Guigang, Yulin. Hengxian population presented the highest sensitive to chlorantraniliprole, with a LC50value of0.0714mg/L, and the relative sensibility factor of Yulin population was2.9, which was the lowest. The order of the sensibility to avermectin was Hengxian, Yongfu, Hepu, Xing’an, Nanning, Fangcheng, Laibin, Yulin, Baise, Guigang. Hengxian population performanced the highest sensitive to avermectin, with a LC50value of0.0331mg/L, and the relative sensibility factor of Guigang was3.31, which was the lowest. The order of sensibility to flubendiamide was Hengxian, Xing’an, Hepu, Yongfu, Baise, Fangcheng, Nanning, Laibin, Guigang, Yulin. Hengxian population performanced the highest sensitive to flubendiamide with a LC50value of0.0331mg/L, and the relative sensibility factor of Yulin population was2.70, which was the lowest. The order of sensibility to chlorantraniliprole-thiamethoxam was Baise, Yulin, Hengxian, Nanning, Xing’an, Yongfu, Laibin, Fangcheng, Hepu, Guigang. Baise population performanced the highest sensitive to chlorantraniliprole·thiamethoxam, with a LC50value of0.1885mg/L, and the relative sensibility factor of Guigang population was2.61times, which was the lowest.3The results of toxicity test showed that the order of sensibility levels of C. medinalis Guenee to8pesticides was avermectin, avermectinand·indoxacarb, avermectinand-four chlorine worm amide, chlorantraniliprole, flubendiamide, four chlorine worm amide, ivermectin, chlorantraniliprole-thiamethoxam. Avermectin had the highest virulence, with a LC50value of0.0433mg/L. Chlorantraniliprole-thiamethoxam had the lowest virulence to C. medinalis Guenee, with a LC50value of0.3620mg/L.4The results of field trials demonstrated that, among different recommended dosage of different pesticides,20%chlorantraniliprole-thiamethoxam and1.8%avermectinand had the worse control effect with83.31%and83.48%when their dosages were60g/hm2and4.05g/hm2, respectively.10%avermectinand-indoxacarb had the best control effect on C. medinalis Guenee, with91.97%when its dosage was45g/hm2. Followed by8%avermectinand-four chlorine worm amide with89.93%when its dosage was60g/hm2. The results of variance analysis demonstrated that, there was no significant difference between them.