Characteristics of biochemical resistance mechanism of novel insecticides in Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae)

Abstract

Phenacoccus solenopsis Tinsley is a major sap-sucking insect pest of many ornamental and agricultural crops in Pakistan. Insecticides are recommended to manage P. solenopsis but due to inappropriate use of insecticides, the resistance become the major concern. The study was conducted to investigate resistance against insecticides with different action modes (carbosulfan, clothianidin and chlorfenapyr) by selecting P. solenopsis populations successively for twelve generations with mentioned insecticides. Along with, possible biochemical mechanisms (acetylcholinesterase (AChE), acid and alkaline phosphatases (ACP and ALP), esterase (EST) and glutathione S-transferases (GST)) were assessed. The results described very high resistance (235-fold) to carbosulfan selected pop. (Carbo-SEL G12) and clothianidin selected pop. (Cloth-SEL G12) (112-fold) and high resistance to chlorfenapyr selected pop. (Chlor-SEL G12) (86-fold), relative to the unselected population. The activities of AChE, ACP, ALP, EST and GST enzymes gradually increased upon selection from G1 to G10. The enzymes contribute in resistance of tested insecticides were following: EST (15.61 μmol/min/mg of protein) in Carbo-SEL G12. Whereas, AChE activity (21.5 μmol/min/mg of protein) in Cloth-SEL G12 and the highest ALP enzymes activity 16.57 μmol/min/mg of protein in Chlor-SEL G12, as compared to the unselected population. Current research suggests that the detoxifying enzymes may contribute to resistance evolvement in P. solenopsis and this information may be used for the efficient management of insecticide resistance.