Resistance selection and biochemical mechanism of resistance against cyflumetofen in Tetranychus cinnabarinus (Boisduval)

• The cyflumetofen-resistant strain of Tetranychuscinnabarinus was obtained with the resistance ratio reached 21.33 at LC50.
• All the collected field strains showed low resistance (resistance ratio ranged from 4.32 to 5.87) against cyflumetofen.
• The GSTs was the most important detoxifying enzyme conferring resistance against cyflumetofen in T. cinnabarinus.

The carmine spider mite, Tetranychus cinnabarinus is an important crop and vegetable plants pest mite. As a novel acaricide, cyflumetofen is effective against Tetranychus and Panonychus mites, but its risk and biochemical mechanism of resistance in mites is not clear. In this study, the resistance against cyflumetofen was selected and its biochemical mechanisms were studied in T. cinnabarinus. After selection the susceptibility and resistance against cyflumetofen in T. cinnabarinus, the final resistance ratio reached 21.33 at LC50 (CyR-43/CyS). All the collected field populations showed low resistance against cyflumetofen, although it had never been used in China. The activity of detoxifying enzymes CarE, MFO and GSTs were significantly increased in the final selected resistance strain (CyR-43), especially that for GSTs increased more than 7-folds after selection. The resistance against cyflumetofen developed slowly when selected from the susceptible strain in laboratory, but the resistant genes already existed in field populations, and the GSTs was the most important detoxifying enzyme conferring resistance against cyflumetofen in T. cinnabarinus. These results would provide the valuable information for designing appropriate strategies for the practical application of cyflumetofen in the field and delaying resistance development.

The activity changes of the three detoxifying enzymes along with the resistant level increase.Figure optionsDownload as PowerPoint slide