Evaluation Of Control Effect Of Chlorantraniliprole On Cnaphalocrocis Medinalis (Guenee) And Its Influence On Rice Growth

The rice leaf folder (RLF), Cnaphalocrocis medinalis (Guenee) is one of the most important pests of rice. Control effects of several insecticides on C. medinalis were studied. Action mode of chlorantraniliprole and enzyme activities on C. medinalis as well as the effect on the development of rice were investigated in this paper. The main results are as follows:1. Biological activities and control effects of several insecticides on C. medinalis larvae were studied. The results of bioassay in laboratory indicated that the biological activitiy to C. medinalis larvae of chlorantraniliprole was the highest (LC50: 0.85 mg/L), followed by emamectin,abamectin,fipronil,PuGV?Bt,profenofos,chlorpyrifos (LC50: 1.09mg/L,2.28mg/L,9.30mg/L,394.17mg/L,582.30mg/L,1120.84 mg/L, respectively). The results of field experiments showed that chlorantraniliprole had the best control effect both in rapid and sustained effectiveness from 3 days to 14days after spraying the insecticides. The organophsphorus and pyrazole were the most effective on the 3rd day after treatment. The control effect of biological insecticides increased significantly at 7 days to 14 days after treatment.2. Chlorantraniliprole which had the highest biological activity and control effect was selected to study its action mode and the effect on activity of protective enzymes and detoxification enzymes of C. medinalis larvae. Results of Action mode tests showed that chlorantraniliprole had three kinds of action mode, the effcets of which from high to low was stomach toxicity > contact toxicity > intake transportation activity. The Results of enzymes activity tests indicated that the activities of peroxidase and glutathione-S-transferase of the C. medinalis larvae which treated with LC50 of chlorantraniliprole increased significantly with treatment time increased.3. The growth of the rice seeding was significantly higher than the control when the seeds were treated by chlorantraniliprol of different concentrations. The height,root length,leaf number,fresh weight of the rice seeding were all significantly higher than the control. The height and leaf length of rice plant were not significantly influenced by chlorantraniliprole spraying. The tiller numbers (total branch number per hole) of the rice plant were not obviously changed at 14 days after treatment when using chlorantraniliprole for controlling 4(2) generation of C. medinalis, while activities of superoxide dismutase(SOD) and peroxidase(POD) in rice leaves decreased significantly.