Monitoring Of Insecticide Resistance And Resistance Risk Assessment For JS118 In The Rice Stem Borer, Chilo Suppressalis (Walker)

The rice stem borer with the Latin name Chilo suppressalis(Walker) is one of the pests in pyralidae family which belongs to lepidoptera. It could cause great damage to rice in the drainage area of the Changjiang River.lt has been always difficult to control for the outbreak of the pest in some areas since 90s of last century. For a long time, populations of Chilo suppressalis(Walker) are mainly used to chemical control. The fact that long time abuse of some pesticide result in insect resistance. To administer and mitigate the resistant problem, we started to monitoring the insecticide resistance and evaluating the risk of JS118.In total,17 populations of Chilo suppressalis Walker were collected from seven rice-growing provinces from 2008 to 2009 in China, and they were used topical bioassay to examine their resistant levels to monosultap. triazophos. chlorpyrifos, fipronil. and abamectin. Results indicated that the resistance levels of the 17 populations to the 5 insecticides were different as various regions where the insect was collected from drainage area of the Changjiang River. The high-level resistant region was the Cangnan, Rui'an. Jiangshan in south of Zhejiang province. Populations from the region developed extremely high to high-level resistance to monosultap (RR=177.0-43.2 fold), triazophos (728.1-238.7), and chlorpyrifos (57.8-31.7). At the same time, they had moderate or low level resistance to fipronil (24.7-11.2) and abamectin (5.9-7.1) which were widely used in recent years; Moderate level resistant region had the Lujiang of Anhui. Youxian of Hunan and Gaochun of Jiangsu province. Their populations had extremely high level resistance to triazophos (379.0-203.2), high to moderate level resistance to monosultap (48.8-18.3) and chlorpyrifos (29.8),and low susceptivity to fipronil (4.4) and abamectin (4.7-4.1); The low resistant region involved in Yizheng of Jiangsu. Hexian of An'hui province.The populations showed high level resistance to chlorpyrifos (45.2) and triazophos (50.0), but moderate level resistance to susceptive to the other insecticides; The areas of Xinyang of He'nan. Lianyungang of Jiangsu and Wusheng of Sichuan province belonged to susceptible region. These populations were low susceptivity or susceptive to most insecticides that were tested except monosultap.According to the monitoring result during 2008 to 2009, resistance management strategies should be proposed based on thel resistant locationIn our laboratory, the LYG05 population has been selected uncontinuously with JS118 for 13 gererations. Compared with the relatively susceptible population, LYG05 population was 2.71 fold resistant to JS118. which is 0.06 times higher than that of pre-selection. Realized heritability(h2) estimated from selection was 0.0139 and showed that the development of resistance to JS118 is very low.