Abstract:

In order to understand the susceptibilities to different insecticides to Cnaphalocrocis medinalis Guenee, Also to screen alternative insecticides for controlling Cnaphalocrocis medinalis Guenee. The populations of Cnaphalocrocis medinalis Guenee were collected from Nanning in Guangxi Province, and their susceptibilities to different insecticides were tested by spraying method of Potter in laboratory. The results showed that: the populations were the most sensitive to emamectin benzoate, the value of LC50 was 3.4595 mg (a.i.)/L, and were also sensitive to silafluofen, cyhalothrin, phoxim, monosultap, alpha-cypermethrin, avermectin, profenofos, triazophos, the values of LC50 were from 6.3490 mg (a.i.)/L to 44.8607 mg (a.i.)/L. Through field trials, we found that 5% silafluofen EW 300, 450, 600 g (a.i.)/hm2 had the best effect on the prevention of Cnaphalocrocis medinalis Guenee, the preventing rate of which reached up to more than 80%, with a top of 87.35%. 1% emamectin benzoate EC 3.6, 4.8, 7.2 g (a.i.)/hm2 and 50% monosultap WP 1125, 1500, 1875 g (a.i.)/hm2 ranked second in this aspect with a rate from 66.05% to 86.70%.