The Comparison Of Susceptibilities In Rice And Water-oat Populations Of Chilo Suppressalis To Different Insecticides

Water-oat is an important economical crop in China. It makes serious economic loss by excessive pesticide residues which leads to the limit of exports. How to make reasonable pest controlment in water-oat field has become a critical issue. Rice stem borer Chilo suppressalis is the main pest in water-oat field. The research shows that the rice and water-oat populations of C. suppressalis have a significant difference in susceptibility to Organophosphate insecticide. To find whether there is significant difference in susceptibilities to other kinds of insecticides is essential for our pest controlling in both water-oat and rice fields.The main results are as follows:(1) Micro-drop method was used for testing susceptibilities in C. suppressalis from both rice population and water-oat population to Organophosphate insecticide (Phoxim and Chlorpyrifos), O-formyl amino benzamides insecticide (Chlorantraniliprole), Nereistoxin insecticide (Monosultap) and Antibiotic insecticide (Avermectin). The susceptibilities in rice population to Phoxim and Chlorpyrifosis are lower than those in water-oat population, susceptibilities to Chlorantraniliprole and Avermectin are also lower than those in water-oat population, while to Monosultap, the susceptibility in rice population is higher than in water-oat population. After comparison, we find susceptibilities in rice and water-oat populations to Avermectin and Chlorantraniliprole have significant difference, while other insecticides don’t.(2) Method was used in testing susceptibilities in C. suppressalis to Cry1Ac、 Cry2Aa and Cry1Ca by newly hatched neonate from two populations. In Bt protoxin, the susceptibilities in rice population to Cry1Ac and Cry2Aa are lower than those in water-oat population, while the susceptibility in rice population to Cry1Ca is higher than water-oat population. And there is no significant difference in susceptibilities to3Bt protoxins between rice population and water-oat population.By analysis:The toxic effects of Avermectin and Chlorantraniliprole on C. suppressalis are the best, followed by Phoxim and Chlorpyrifos, the effect of Monosultap is the worst. While on Bt protoxin, Cry1Ca is the best, followed by Cry1Ac, and Cry2Aa is the last. In pest controlling, rice population fits with a higher content of Avermectin and Chlorantraniliprole compared to water-oat population. While water-oat population in the field needs a lower content to prevent pest resistence and excessive pesticide residues. We could mix those insecticides of different functions to make the prevention more efficiency and finally prevent pest resistant.The study that in Avermectin and Chlorantraniliprole, there is a significant difference on susceptibility between water-oat and rice populations of C. suppressalis provides us a scientific theory in controlling C. suppressalis from water-oat field and rice field separately. And it also provides us some help in further research for host population’s formation.