Cross-resistance, inheritance and biochemical mechanism of abamectin resistance in a field-derived strain of the citrus red mite, Panonychus citri (Acari: Tetranychidae).

BACKGROUND: The citrus red mite, Panonychus citri (McGregor), a global pest of citrus, has developed different levels of resistance to various acaricides in the field. Abamectin is one of the most important insecticides/acaricides worldwide, targetting a wide number of insect and mite pests. The evolution of abamectin resistance in P. citri is threatening the sustainable use of abamectin for mite control.

RESULTS: The abamectin resistant strain (NN-Aba), derived from a field strain NN by consistent selection with abamectin, showed 4279-fold resistance to abamectin compared to a relatively susceptible strain (SS) of P. citri. Cross-resistance of NN-Aba was observed between abamectin and emamectin benzoate, pyridaben, fenpropathrin and cyflumetofen. Inheritance analyses indicated that abamectin resistance in the NN-Aba strain was autosomal, incompletely recessive and polygenic. The synergy experiment showed that abamectin toxicity was synergized by piperonyl butoxide (PBO), diethyl maleate (DEM) and tributyl phosphorotrithiotate (TPP) in the NN-Aba strain, and synergy ratios were 2.72-, 2.48- and 2.13-fold, respectively. The glutathione-S-transferases activity in the NN-Aba strain were significantly increased by 2.08-fold compared with the SS strain.

CONCLUSION: The abamectin resistance was autosomal, incompletely recessive and polygenic in P. citri. The NN-Aba strain showed cross-resistance to various acaricides with different modes of action. Metabolic detoxification mechanism participated in abamectin resistance in NN-Aba strain. These findings provide useful information for resistance management of P. citri in the field. © 2023 Society of Chemical Industry.