Fenpyroximate resistance in Tetranychus urticae (Acari: Tetranychidae): cross-resistance and biochemical resistance mechanisms.
A field colony of the Two-spotted spider mite, Tetranychus urticae (Koch), resistant to fenpyroximate was further selected with fenpyroximate 5SC for 20 generations at a selection pressure of 30-50% mortality (designated as FR-20 strain). Resistance and cross-resistance levels of the FR-20 strain to 18 acaricides were determined using a spray method. The FR-20 strain was extremely resistant to fenpyroximate [resistance ratio (RR) 252]. The strain exhibited extremely strong positive cross-resistance to acrinathrin (RR 196), and high levels of resistance to benzoximate (RR 55) and propargite (RR 64). Moderate levels of cross-resistance (RR 11-40) to abamectin, fenbutatin oxide, fenpropathrin, pyridaben, pyridaben + bifenthrin and tebufenpyrad were observed. The FR-20 strain showed low levels of resistance (RR < 10) to azocyclotin, bromopropylate, chlorfenapyr, chlorfenapyr + bifenthrin, chlorfenapyr + pyridaben, dicofol, fenazaquin and milbemectin. Synergist experiments with different metabolic inhibitors revealed that piperonyl butoxide had the greatest effect on the efficacy of fenpyroximate, followed by iprobenfos and triphenyl phosphate. In a comparative assay with detoxifying enzymes, the FR-20 strain showed 2.5-fold higher activity in p-nitroanisole-O-demethylation, and 2.5- and 2.2-fold higher activities in alpha- and beta-naphthyl acetate hydrolysis, respectively. These results suggested that enhanced activities of both mixed-function oxidases and esterases likely contribute to the fenpyroximate resistance of the FR-20 strain of T urticae.
School of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Republic of Korea.
Young-Joon
YJ
Kim
Si-Hyeock
SH
Lee
Si-Woo
SW
Lee
Young-Joon
YJ
Ahn
D000818:Animals; D001565:Benzoates / Q000494:pharmacology*; D003433:Crosses, Genetic; D004950:Esterases / Q000378:metabolism*; D005260:Female; D007305:Insecticide Resistance / Q000235:genetics / Q000502:physiology; D007306:Insecticides / Q000494:pharmacology*; D007928:Lethal Dose 50; D008297:Male; D010088:Oxidoreductases / Q000378:metabolism*; D010574:Pesticide Synergists; D011720:Pyrazoles / Q000494:pharmacology*; D040102:Tetranychidae / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics
D001565:Benzoates; D007306:Insecticides; D010574:Pesticide Synergists; D011720:Pyrazoles; C415144:fenpyroximate; D010088:Oxidoreductases; D004950:Esterases