Potential Toxicity of Selected Insecticides to Rice Leafhoppers and Planthoppers and their Important Natural Enemies

Abstract

Potential toxicity of selected insecticides to rice brown planthopper (BPH), Nilaparvata lugens , whitebacked planthopper (WBPH), Sogatella furcifera , green leafhopper (GLH), Nephotettix virescens and their important predators in rice ecosystem, viz., green mirid bug, Cyrtorhinus lividipennis , brown mirid bug, Tytthus parviceps and veliid predator, Microvelia douglasi atrolineata was assessed in the greenhouse. Among the single compound insecticides, spinosad was moderately toxic to BPH followed by flubendiamide while ethiprole and indoxacarb were not effective against BPH, WBPH and GLH. Flubendiamide was least toxic to green mirid bug compared to acephate and other insecticides. Ethiprole and spinosad were less toxic to nymphs of brown mirid bug. Individually ethiprole, spinosad, flubendiamide were less toxic to Microvelia , but indoxacarb was more toxic. Ethiprole+imidacloprid and thiamethoxam+lambdacyhalothrin exhibited excellent initial and persistent toxicity against BPH, WBPH and GLH, but these two combination products were also highly toxic to all the three natural enemies recording 100% mortality within 24 hours. Flubendiamide+fipronil exhibited moderate toxicity against BPH, but was less effective against WBPH and ineffective against GLH. However, this product was highly toxic to both the mirid bugs and relatively less toxic to veliid bug.