Abstract:

【Objective】 This study monitored the resistance to nine insecticides in different populations of the striped stem borer, Chilo suppressalis (Walker), collected from Zhejiang and Jiangsu provinces in 2007, sensitivity of Donghai population to 20 insecticides was evaluated as well. The results have provided useful information for the resistance management strategies of the striped stem borer. 【Method】 Topical application method was used in the experiment. 【Result】 The results showed that Rui’an, Cangnan and Gaochun populations developed extremely high levels of resistance to monosultap (164.8 to 248.1 fold), and Lianyungang and Donghai populations had moderate levels of resistance (18.1 and 25.1 fold respectively). The resistance to triazophos varied greatly in five populations, from having extremely high levels of resistance in Rui’an, Cangnan and Gaochun populations (204.8 to 1395.2 fold), to being susceptible in Lianyungang and Donghai populations (1.8 and 3.1 fold respectively). Moderate resistance levels to fipronil were monitored in Rui’an and Cangnan populations (12.3 and 26.8 fold respectively), while other three populations tested were susceptible to fipronil (1.3 to 2.9 fold). A low level of resistance to abamectin was detected in Cangnan population (7.6 fold), and other four populations tested remained susceptible to abamectin (0.9 to 2.0 fold). Rui’an and Cangnan populations had moderate or high levels of resistance to cyhalothrin, fenvalerate, beta-cypermethrin, beta-cyfluthrin and deltamethrin (22.1-115.6 fold), while Lianyungang, Donghai and Gaochun populations had low or moderate levels of resisitance to cyhalothrin, fenvalerate, beta-cypermethrin, beta-cyfluthrin and deltamethrin (31.2-5.3 fold). The sensitivity to 20 insecticides was evaluated in Donghai population of Jiangsu province. The toxicity sequence of 20 insecticides to the population was as follows: abamectin, emamectin benzoate＞ivermectin, beta-cyfluthrin＞butene-fipronil, fipronil, fenvalerate, cyhalothrin, deltamethrin, beta-cypermethrin, tebufenozide≥phoxim, quinaphos, furan-tebufenozide, triazophos, pyridaphenthion＞malathion, chlorpyrifos, silafluofen＞monosultap. 【Conclusion】 The resistances to insecticides varied significantly with populations of the striped stem borer, so the resistance management strategies should be proposed according to the local situation.

Key words: striped stem borer, resistance, toxicity, insecticides, pyrethriods