Field resistance monitoring of Apolygus lucorum (Hemiptera: Miridae) in Shandong, China to seven commonly used insecticides

Abstract

Recently, due to the decreased usage of broad-spectrum insecticides in transgenic Bt cotton in China, Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) has emerged as a major pest of cotton and other agricultural crops. A glass vial bioassay method was used to evaluate the resistance in the Shandong populations of A. lucorum to seven commonly used insecticides during 2009–2014. For organophosphate insecticides, there was no resistance to malathion in most of the collected populations, and resistance ratios were 1.2–5.6-fold for chlorpyrifos in comparison to a susceptible Juye strain. For pyrethroid insecticides, the resistance of three populations (Juye, Huimin and Xiajin) showed an upward tendency during the six studied years, and the resistance levels were 2.0–19.5-fold for bifenthrin and 1.1–8.2-fold for lambda-cyhalothrin, but the efficiency of bifenthrin remained high because its LC50 value was very low (LC50 < 50.9 ng/cm2) compared to the LC50 values of other insecticides. For carbamate insecticides, the resistance ratios ranged from 1.6 to 19.0-fold for methomyl and 1.3–5.5-fold for carbosulfan. For phenylpyrazole insecticides, there was moderate resistance to fipronil (up to 31.3-fold). The resistances of A. lucorum to insecticides have developed slowly in Shandong, except the resistance of the Juye population to fipronil. Therefore, malathion, chlorpyrifos, bifenthrin and carbosulfan can still be employed in integrated pest management (IPM) programs supplemented with physical and biological control methods.