Fipronil resistance in the whitebacked planthopper (Sogatella furcifera): possible resistance mechanisms and cross-resistance.
BACKGROUND
The whitebacked planthopper (WBPH), Sogatella furcifera (Horváth), is a major rice pest in many parts of Asia. Fipronil has been widely used to control rice pests, and resistance to fipronil has been reported in some important species.


RESULTS
A field population (F) of WBPH was collected, with 50.5-fold resistance to fipronil, which increased to 137.5-fold (F-se) after continuous selection for 11 generations. The F-se population did not show significant cross-resistance to the insecticides examined by comparison with the F population. TPP (synergism ratio 1.9), DEM (1.5) and PBO (1.1) showed only slight synergism on fipronil in the F-se population. A large increase was found in esterase and P450 monooxygenase activity in the F-se population. In vitro, PBO inhibited both esterase and P450 monooxygenase activity, and TPP inhibited esterase activity in the F-se population.


CONCLUSIONS
Synergistic study in vivo and biochemical study in vitro indicated that esterase and P450 monooxygenases might be important factors for fipronil resistance in the selected population F-se. However, these biochemical factors could not lead to such high resistance (137.5-fold) in the F-se population, and target-site insensitivity would be another or more important factor.
Tang
Jian
J
Rice Technology Research and Development Centre, China National Rice Research Institute, Hangzhou, China.
Li
Jian
J
Shao
Ying
Y
Yang
Baojun
B
Liu
Zewen
Z
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004950:Esterases / Q000378:metabolism; D006430:Hemiptera / Q000187:drug effects* / Q000201:enzymology; D019476:Insect Proteins / Q000378:metabolism; D007305:Insecticide Resistance; D011720:Pyrazoles / Q000494:pharmacology*
D019476:Insect Proteins; D011720:Pyrazoles; D003577:Cytochrome P-450 Enzyme System; D004950:Esterases; C082360:fipronil