Control Effect of the Mixture of Abamectin and Bacillus Thurmgiensis (B.t) on Cnaphalocrocis medinalis and Chilo suppressalis

Co-toxicity coefficiency (CTC) of a mixture of abamectin and bacillus thurmgiensis (Bt) to the Cnaphalocrocis medinalis was tested in laboratory. The CTC was 147.73. The result showed the mixture had a significant synergism effect. Basing on the proper proportion of abamectin to Bt, we manufactured the compound of abamectin + Bt WP. The results of trials on field in 2000 and 2001 showed that the compound had a good effect on controlling C. medinalis and C. suppressalis. At the dosage of 120 g/667m2, 100 g/667m2, 80 g/667m2, the roller-killing rates to C. medinalis were 94.74% and 95.08%, 87.50% and 91.80%, 84.58% and 86.88% respectively. At the same dosage, the efficiency of dead heart rates to C. suppressalis were 84.61% and 86.40%, 79.71% and 82.06%, 73.50% and 74.44%, respectively. The mixture has a lower toxicity to mammals, so it can be used to protect environment and produce green-rice.