The Control Effects Of Fipronil And Other Insecticides On Three Rice Insects And Impacts On Their Predator

Screening insecticide for rice insect is very important because 5 high toxicity organophosphorus pesticides ( methamidophos. parathion-methyl etc ) will be prohibited in china from jan.1 .2007.The control effects of the 4 insecticides: fipronil, chlorpyrifos. abamectin and deltamethrin on the main rice insects as rice thrips. rice stem borer, rice leaf folder and the impacts on the main predators as rice field spider, geocoris sp., brumoides hainanesis, Paederus sp. Cyrtorrhinus lividipennis Reuter in rice field were studied. The results shows that:The control effects of sprayying them in the seedling period, by the amount of 5% fipronil 30 mL/667m2, 48% chlorpyrifos EC 60 mL/667m2, 2% abamectin EC 20 mL/667m2, 2.5% deltamethrin 30 mL/667m2 to control rice thrips, on rice thrips are 92.8%, 92%, 92.9%, 88.5% respectively. The effects of them all are higher than that of methamidophos (87.3%). The effects of protecting leaves are 71.3%. 80.4%. 70.4%. 76.2% respectively, which are similar as methamidophos (79.6%). But in the seedling period , the difference among the killing effects of the 4 insecticides on predators are very distinctness. 7 days after spraying them, the killing effects of them on spider are 36.24%, 48.42%, 26.15%, 91.63% respectively (67.85% for methamidophos 100 mL/667m2) and the killing effects of them on Geocoris sp. are 50%, 83.1%. 47.7%, 92.6% respectively ( 93.8% for methamidophos).In the field period, the 4 insecticides are sprayed to control rice leaf folder and rice stem borer. 7 days after spraying them, by the amount of 5% fipronil 30 mL/667m2, 48% chlorpyrifos EC 60 mL/667m2, 2% abamectin EC 20 mL/667m2. 2.5% deltamethrin 30 mL/667m2 to control rice leaf folder, the control effects are 90.3%, 89.4%, 85%, 82.1%, respectively ( 83.6% for methamidophos ) . 15 days after application of them, the effects of protecting leaves are 77.0%. 78.9%, 76.6%, 75.1%.respectively (72.7% for methamidophos ). 7 days after sprayying them, the control effects on rice stem borer are 98.5%, 96.9%, 96.9%, 78.5%, respectively (72.7% for methamidophos ). 21 days after that, the control effects on rice stem borer are 100%,95.2%, 100%, 38.1 %, respectively. (56.2% for methamidophos ) the effects of protecting leaves are 100%, 100%, 100%, 53.8%, respectively ( 56.2% for methamidophos ).The impacts of 4 insecticides applied in field period on their predators are different. For rice field spider, the impacts of abamectin and fipronil on their predators are lighter than that of deltamethrin and chlorpyrifos, proofread growth and decline rate of insect amount in the deal with abamectin or fipronil is lower than that of deltamethrin or chlorpyrifos. 3 days after spraying with 48% chlorpyrifos EC 60 Ml/667m2, 2% abamectin EC 20 mL/667m2 and 2.5% deltamethrin 30 mL/667m2. growth and decline rate 减退率 of rice field spider is -21.3%. -41.3%. -6.0% and -72.0% , respectively, ( -81.2% for methamidophos ); 21 days after that, growth and decline rate of rice field spider is -17.8%, -72%, -3.4% and -72.9%, respectively. (-73.9% for methamidophos ).The killing effect of deltamethrin and chlorpyrifos on Paederus sp. is most strong, The killing effect of fipronil on Paederus sp. is lighter, the impacts of abamectin on Paederus sp. is basically zero. 3 days after spraying the insecticides, proofread growth and decline rate of Paederus sp. for all controls is -15.4%, -50%, 0, -70%, -88.9%, respectively; 21 days after that, proofread growth and decline rate of Paederus sp. for all control is -13.4%, 51.8%. -6.2%, -55.0%, -58.3%, respectively.The impacts of abamectin and fipronil on Cyrtorrhinus lividipennis Reuter is lighter than of deltamethrin and chlorpyrifos ; the impact of deltamethrin on Cyrtorrhinus lividipennis Reuter is most heavy. 3 days after spraying insecticides, proofread growth and decline rate of Cyrtorrhinus lividipennis Reuter for all controls is -16.5%, -49.9%, -5.9%, -68.7%, respectively ( -84.5% for methamidophos ); 21 days afte that, proofread growth and decline rate of Cyrtorrhinus lividipennis for all controls is...