Field Screening Experiments for the Substituted Agrochemicals of Imidacloprid

Field screening experiments for the substituted agrochemicals of imidacloprid were processed. When fipronil 5% SC applied at 750 mL/ha, dursban plus fipronil 48% EC applied at 900 mL/ha and pymetrozine 25% WP applied at 300 g/ha in field plot trials respectively, they provided above 80% control efficacy against both brown planthopper and small brown planthopper at 10 d after application, and provided over 75% control efficacy against white backed rice planthopper at the same time. While the control efficacy of imidacloprid 10% WP applied at 600 g/ha against those three kinds of planthopper were all less than 50%. When they were used at the same dosage in field demonstration trials, the control efficacy against planthopper in rice field at 10 d after application is 82.6%, 85.2% and 76.9%, and against small brown planthopper in cornfield at 15 d after application is 83.9%, 79.9% and 82.4%, respectively. The results showed that the control efficacy of the three agrochemicals to planthopper is better than that of imidacloprid. Thus, fipronil, dursban plus fipronil and pymetrozine may be the substituted. agrochemicals of imidacloprid. In addiiton, the technique of the three agrochemicals used in field was discussed.