Study On The Identification Of Biotypes, Resistance Monitoring, Formula Selection Of Pesticide And Synergism Biochemical Mechanism Of Bemisa Tabaci (Gennadius)

Bemisa tabaci (Gennadius) is an agricultural pest in the world, and makes a serious economic loss to agricultural production. In recent years, because the problems of blindly and irrationally application of pesticides, it has led to the occurrence and development of resistance of Bemisa tabaci, and outbreaks of the disaster frequently in many areas, the control becomes difficult. So it is very urgent and important to develop the resistance control and comprehensive treatment on Bemisa tabaci. In this paper, the biotypes and distribution of Bemisa tabaci has been made clear, resistance monitoring, formula selection in the lab and synergism biochemical mechanism of Bemisa tabaci were studied, and it is very beneficial to the resistance control and intergrated pest management on Bemisa tabaci.Mitochondrial cytochrome oxidase I (mtDNA COI) gene sequences were utilized as a marker to identify biotypes of B. tabaci population in Hubei province. The results showed that, the Bemisa tabaci population from Dangyang, Xiantao, Tianmen, Jianli, Yichang and Wuhan belonged biotype Q, where Zaoyang was biotype B.The agar leaf dip method was used to measure the resistance of Bemisa tabaci field populations from Wuhan, Xiantao, Dangyang, Zaoyang respectively to nine insecticides in the year 2008 and 2009, the results indicated that Bemisa tabaci field populations produced different level of resistance, and the whole presented the downward trend. The ratio of resistance on emamectin benzoate and abamectin were 14.3-35.5,9.8-16.9 respectively, the ratio of resistance on imidacloprid, acetamiprid, nitenpyram were 8.4-21.0,28.6-49.9,5.5-15.5, the ratio of resistance on fipronil, diafenthiuron, carbosulfan, acephate were 3.0-7.6,7.7-14.4,2.6-1.9,37.5-93.3. The synergism formulas and optimum ratio of the nine insecticides were selected with the methods of the interactivity testing and CTC, the results showed that emamectin benzoate and imidacloprid optimum synergism ratio which was 1:84, with CTC of 350.55. The combination of nitenpyram and diafenthiuron, nitenpyram and abamectin, nitenpyram and fipronil had certain additive action. The control effect of the combination above was higher than the single doses after field experiments.Biochemical analysis was conducted to studied the 3 kinds of detoxifying enzyme activities of different Bemisa tabaci strains, which were field resistance and susceptible strain. The results showed that the synergism mechanism had close relationship MFO activity, and it had not inevitable connection to CarE and GSTs.