Influence of insecticide application and flying predators on insect abundance in a suburban paddy field

Abstract

This study examined the effects of natural predators and insecticides for pest control to achieve effective integrated pest/biodiversity management. Four 7-m2 experimental plots were set in a suburban paddy field, with or without netting (20-mm mesh to exclude large flying predators) or pyrethroid insecticide application. Insecticide application decreased the abundance of Hemiptera, Orthoptera, Coleoptera, and Diptera and netting increased those of Hemiptera and Orthoptera. Hemipteran insects, which are main pests of rice plants, comprised 85% of the total insect abundance. With insecticide application, the abundance of Nilaparvata lugens decreased, with netting the abundance of Laodelphax striatellus increased and with both, the abundance of Nephotettix cincticeps, Recilia dorsalis, Psammotettix striatus, and Empoasca vitis changed. Our simple experiment showed that flying predators were as effective at reducing rice pest populations as insecticide application, whereas insecticide reduced non-pest insect populations.