title: Insecticide resistance status of field populations of Spodoptera exigua (Lepidoptera: Noctuidae) from China.
abstract: Beet armyworm, Spodoptera exigua (Hübner), is a serious pest of vegetables in China, and its control is heavily dependent on chemical insecticides. The current resistance status of nine insecticides was investigated in 16 field populations collected from seven provinces of China during 2009-2012. Compared with the susceptible strain WH-S, some field populations evolved various levels of resistance to eight of the nine insecticides tested: emamectin benzoate (4- to 348-fold), indoxacarb (2- to 41-fold), spinosad (5- to 38-fold), chlorantraniliprole (2- to 44-fold), tebufenozide (2- to 87-fold), chlorfluazuron (3- to 31-fold), cypermethrin (79- to 1240-fold), and chlorpyrifos (8- to 3,080-fold), but no significant resistance was detected to chlorfenapyr (0.4- to 7-fold). This indicates that chlorfenapyr has no cross-resistance with these other currently used insecticides. Four consecutive years' resistance screening at two places shows that resistance patterns were different between populations from Luhe (Jiangsu Province) and Fengxian (Shanghai), which are approximately 300 km apart. Resistance levels to chlorpyrifos were much higher in populations from Luhe (877- to 3,080-fold) than from Fengxian (8- to 110-fold). Fengxian populations developed moderate levels of resistance to tebufenozide (13- to 87-fold), but no resistance in Luhe populations (2- to 6-fold). However, Luhe populations developed moderate levels of resistance to chlorfluazuron (21- to 31-fold), but there was no resistance in Fengxian populations (3- to 5-fold). It is suggested that local insecticide selection determined resistance patterns although S. exigua has long-distance migratory potential. Adaptive resistance management tactics (such as rotations) should be designed and implemented based on the resistance patterns of S. exigua for each geographic area.
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Wunan
authors.initials: W
authors.lastname: Che
authors.forename: Tian
authors.initials: T
authors.lastname: Shi
authors.forename: Yidong
authors.initials: Y
authors.lastname: Wu
authors.forename: Yihua
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000818:Animals; D002681:China; D007300:Insect Control; D007305:Insecticide Resistance / Q000187:drug effects*; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D012641:Selection, Genetic; D018411:Spodoptera / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development
chemical_list: D007306:Insecticides