Monitoring Of Resistance Of Chilo Suppressalis To Fipronil And Other Pesticides And The Research Advance Management

Striped stem borer, Chilo suppressalis (Walker),is one of major insect pests ofrice in China, especially in the valley of Changjiang River. In recent 10 years,population of this pest and its damage to rice increased dramatically,severelythreatening the high and stable yields of rice. For a long time, populations of C.suppressalis are controlled mainly by the use of chemical insecticides. Insecticideresistance in C. suppressalis was one of the main factors for its infestation increase.During 2005 to 2006, insecticide resistance was determined with populationsfrom five provinces Hunan, Hubei, Zhejiang, Jiangsu and Jiangxi.Most populations examined remained susceptible to fipronil. However, in2005,for the first time, Shaodong was found to have 1.4-fold resistance only and thetopmost county, Nanchang was found to have 6.0-fold resistance; in 2006,Li countywas found to have 1.36-fold, but resistance ratios for these three populations were5.27-fold(Yizheng),5.09-fold (Jinhua),6.09- fold (Nanchang)and 5.36-fold(Xinjian).In 2006, Triazophos, was found to have 70.4-129.3-fold resistance, Monosultapwas 30.5-78.9-fold, chlorpyrifos was 4.4-29.7-fold, abamectin was 18.4-37.6-fold,The all pesticides had moderate resistance, Triazophos had high or extremely highresistance.Synergism studies on PY-t strain showed that TPP and DEM had no effect onsusceptible ones. But they had significant synergism to fipronil in resistant borers.PBO and had neither synergistic nor antagonistic action with fipronil, suggesting thatfipronil resistance in the strain had no close relations with piperonyl butoxide (PBO).The field examination to Jinhua in Zhejiang province, Nanchang in Jiangxi province and Liling in Hunan province showed: Fipronil of 5 percent was the best toprevent and control paddy rice Chilo suppressalis,and it could keep long time,maintained an adequated supply of seedlings the effect to be good.