| In order to solve a series of problems that the pollution of surroundings, "3R" and the bad quality of rice were caused by application of large quantity pestticide; To serch after the new approaches of congtrolling the Cnaphalorocis medinalis Guenee and Planthopper; To serch the measure of socially harmless controlling techology, and to reduce the use of chemical pesticides, which is significant to ensure the better quality of rice. In the thesis, determination compatibility of Beauveria bassiana and Bacillus thuringiensis B. thuringiensis (Bt) with four biological pesticides and two chemical pesticides in order to provide the basis of mixturing pesticides; At the same time, the virulence of several biological pesticides to C. medinalis and N. lugens were determined to screen the high virulence biological pesticides; The field trials of some bilogical pesticides and mixture with other pesticides on C. medinalis and Rice Planthopper were made to search the application of techology in field.1 Compatibility of six pesticides with Beauveria Bassiana and Bacillus thuringiensisThe effect of six pesticides at differrent concentration on mycelial growth of B. bassiana were discussed. The results showed that 0.5% veratridine WP,48% chlorpyrifos EC and 5% rengent EC had good compatibility with B. bassiana at conventional field use concentrations, with the mycelia growth inhibition were less than 18%.But 2.5% retenone EC,1.8% avermenctin EC,0.36% matrine AS had strong restrain capability, with the inhibition exceeded 65%. The effect of six pesticides at differrent concentration on colony growth of Bt were discussed. The results showed that 0.5% veratridine WP,1.8% avermenctin EC,48% chlorpyrifos EC,25% buprofezin WP had no inhibitory effect on Bt at conventional field use concentrations, and the inhibition were lower than 14%; However, 2.5% retenone EC and 0.36% matrine AS have some inhibition to the colony growth of Bt with the inhibition were more than 40%. Therefore, B. bassiana and B. thuringiensis could combiled with pesticides with good compatibility.2 The virulence of several biological pesticides to Cnaphalocrocis medinalis Guenee and Nilaparvata lugens in lab The virulence of five biological pesticides to the 3th instar larvae of the C. medinalis were determined by insect-soaking method, the result show that Bt SC,0.5% veratridine WP,2.5% retenone EC and B. bassiana WP had a high toxicity to C. medinalis. And the ajusted motality rates were between 81.82% and 90.90%.The virulence of four biological pesticides to the 3th nymph of the N. lugens were determined with the dipping seedling method, the result show that 0.5% veratridine WP,2.5% retenone EC, B. bassiana WP, and 0.36% matrine AS had a high toxcity effect on N. lugens, and the ajusted motality rates were 83.72%,80.36%,78.95% and 81.34%.3 The field trials of 5 biological pesticides on Controlling Cnaphalocrocis medinalisThe efficacy of 5 biological insecticides against the lower instar larvae of C. medinalis were tested. The results showed that the control effects of 0.5% veratridine WP,2.5% retenone EC, abamectin 1.8% EC, B. thuringiensis 2000IU/μl SC, B. bassiana 4.0×1010 spores/g WP respectively at 3000 g/hm2,4500 mL/hm2,1200 mL/hm2,6000 mL/hm2 and 2400 g/hm2 were between 90.30% and 94.60% in the seventh day after spraying the pesticides; and the effects of protective leaves were between 70.45%-84.09% in the fifteenth day. Compared with 48% chlorpyrifos EC at 50 mL/667m2, the differences of the control effects were not notable, but these biological insecticides took effect more slower than the chemical insecticide chlorpyrifos. When mixing the two pesticides respectively at a half of the recommended dose that was sprayed alone, the control efficacy were significantly more quick than those of the insecticides they were sprayed respectively, the controlling effects were between 84.00%-92.96% in the third day, the effects of controlling larvae in the seventh day and protectiving leaves in the fifteenth day were similar or better than those of spraying the single insecticide respectively. So the 5 biological insecticides can substitute partly for chemical insecticides to control lower instar larvae of C. medinalis.4 The controlling Efficiency of several biological pesticides and Chemical pesticides and their mixtures against PlanthopperThe control effects of 5 biological insecticides against the younger nymphs of N. lugens, the field trials were made in rice through field spray in August 2008.The results showed that,7 days after single spray respectively at a dosage of 3000 mL/hm2 and 1800 g/hm2, the control effects of 0.5% veratridine WP and 4.0×1010 spores/g B. bassiana WP were better, i.e.78.63% and 79.00% respectively, but these biological insecticides took effect more slower than chemical insecticides. When the two pesticides were mixed at a half dosage of the recommended dosage for spraying alone, the control efficacy of B. bassiana +buprofezin was the best, i.e.65.03% in 1 day and 87.60% in 7 days after treatment.Control effects of four biological insecticides and two chemical Pesticides and mixtures of them to mixed population of N. lugens (Stal) and Sogatella furcifera (Horvath) were tested in rice field in August 2009. The results showed that, among 0.36% matrine AS 1500 mL/hm2,0.5% veratridineWP 3000 g/hm2,1.8% abamectin EC 900 mL/hm2 and 4.0×1010 spores/g B. bassiana WP 1800 g/hm2, the control efficiency of abamectin sampled 7 days and 14 days after spraying pesticides were best,73.34% and 82.28% respectively. Among the 8 treatments of the 4 biological pesticides were mixed with the 2 chemical pesticides respectively at a half of recommended dosage for spraying alone, the control effects of the 6 treatments, i.e.①matrine+chlorpyrifos,②veratridine+ chlorpyrifos,③avermectin+chlorpyrifos,④B. bassiana+chlorpyrifos,⑤matrine+ buprofezin,⑥veratridine+buprofezin, were respectively between 81.82%-89.20%, between 88.24%-96.54%, between 95.68%-98.19%, and between 86.02%-97.81% in 1,3, 7,14 days after application of insecticides. The controlling efficiency of the biological pesticides mixed with the chemical insecticides were evidently better than those of the single biological insecticide. So the authors suggest to use these six kinds of mixtures and the dosages for controlling younger nymphs of N. lugens and S. furcifera complex.
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