LAUSR

Wheat aphids are serious pests in wheat growing areas of China, and can lead to from 10% to over 30% reduction in wheat production (Wang et al., 2006). The main wheat aphids are Sitobion avenae (Fabricius), Rhopalosiphum padi (Linnaeus), Metopolophium dirhodum (Walker), and Schizaphis graminum (Rondani). In the Huang-Huai area of China, the dominant wheat aphid species are S. avenae and R. padi. For many years, farmers have applied chemical pesticides to control wheat aphids. The number of wheat aphids in north China has increased from year to year, probably due to the increased resistance to insecticides. In the insect-insecticide ecosystem, the most prevalent resistance mechanism is the metabolic resistance caused by elevated activities of detoxification enzymes carboxylesterases (CarEs), cytochrome P450 monooxygenases (P450s), and glutathione S-transferases (GSTs) (Rufingier et al., 1999; Puinean et al., 2010; Cui et al., 2015). In order to evaluate resistance status, eight field populations of S. avenae and three populations of R. padi were collected from Heilongjiang, Hebei, Shandong, Henan, and Shaanxi