Abstract:

The study aims to delay the resistance of Cnaphalocrocis medinalis to insecticides, and verify the control effect of the new insecticide scheme on Cnaphalocrocis medinalis, thus providing reference for the scientific control. Two treatments were set up: chlorfenapyr·lufenuron 24% SC 750 g/hm², and chlorfenapyr·lufenuron 24% SC 450 g/hm²+ indoxacarb 150g /L SC 300 g/hm². Chlorfenapyr·8% 2100 g/hm² and water (CK) were the control treatments. The field control effect was determined in different fields and on different rice strains. The results showed that each combination treatment had a high control effect on Cnaphalocrocis medinalis. In the Ningbo experiment, the control effect on Cnaphalocrocis medinalis was over 85% three days after the application of chlorfenapyr·lufenuron 24% SC 750 g/hm² and chlorfenapyr·lufenuron 24% SC 450 g/hm²+ indoxacarb 150g /L SC 300 g/hm² in early rice or single-cropping rice fields, and the control effect was over 90% after 7 days. After 14 days, the leaf retention rates of the two treatments were both over 90%. In the Wenzhou experiment, the control effect of chlorfenapyr·lufenuron 24% SC 750 g/hm² and chlorfenapyr·lufenuron 24% SC 450 g/hm²+ indoxacarb 150 g/L SC 300g/hm² on single-cropping rice was over 85%, which was consistent with that of the Ningbo experiment, and the control effect after 7 days was over 93%, and after 14 days, the leaf retention rates of the two treatments were also over 90%. The control effect and leaf retention rate of each treatment were better than those of CK. The experiment showed that chlorfenapyr·lufenuron 24% SC and indoxacarb 150 g/L SC were high-effective and fast-acting, and had long-lasting control effect on Cnaphalocrocis medinalis.

Key words: Cnaphalocrocis medinalis, chlorfenapyr, lufenuron, indoxacarb, control effect, leaf retention rate, suspension concentrates(SC)