ÃÞ »¨ ѧ ±¨ Cotton Science 2008£¬20(5)£º359-363
Monitoring of Early Stage Resistance to Novel Classes of Insecticides in Spodoptera exigua (Lepidoptera £ºNoctuidae) Abstract£ºSeveral classes of new insecticides with novel mode of action, such as emamectin benzoate, abamectin, indoxacarb, chlorfenapy, methoxyfenozide, JS118 and tebufenozide were developed or introduced to control the beet armyworm, spodoptera exigua (H¨¹bner) in China . Resistance of this pest to many conventional insecticides has been reported in different countries and areas, but there is few evidence of resistance to these new insecticides in beet armyworm as yet. In order to make good use of these new insecticides and implement effective resistance management strategy, susceptibility to several classes of new insecticides was determined using leaf-dipping method in field populations of Spodoptera exigua from six areas of Jiangsu and Henan Province , in China . The results showed that in all six field populations tested with abamectin, three populations from Fengxian and Fu'ning counties, Jiangsu province and Henan province were susceptible or had decreased susceptibility (2.5¡«4.4-fold), one population from Dafeng county, Jiangsu province developed low level resistance (5.2-fold), and two populations from Jiangning and Sheyang counties, Jiangsu province first developed moderate levels of resistance (10.4¡«14.2-fold). In all four populations tested, three populations from Henan province and Jiangning, Fu ' ning and Fengxian of Jiangsu province were susceptible (2.3¡«2.9-fold) to indoxacarb except that one population from Fengxian of Jiangsu province had low level of resistance (6.8-fold) to indoxacarb. Four populations from Henan province and Jiangning, Fu ' ning and Sheyang counties of Jiangsu province were susceptible to emamectin benzoate (RR0.6¡«2.0-fold). In case of chlorfenapy, all four populations tested were susceptible (1.5¡«2.7-fold). Similarly, all populations tested were susceptible to methoxyfenozide (0.4¡«1.7-fold) and JS118 (0.3¡«1.3-fold). In all six populations tested with tebufenozide, four populations from Dafeng, Jiangning and Fengxian of Jiangsu province and Henan province were susceptible (1.6¡«2.5-fold), and two populations from Fu ' ning and Sheyang, Jiangsu province had decreased susceptibility (3.2-fold). These results provide a guideline for developing a more effective resistance management program for beet armyworm.
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