Thirty-five insecticides used on rice in Asia were tested in the field againstNilaparvata lugens. The most important predators of the pest,Cyrthorhinus lividipennis,Microvelia atrolineata, and predacious spiders,Lycosa pseudoannulata,TetragnathaandAraneusspecies, were also momtored in the test plots. Ten insecticides significantly reduced numbers ofN. lugens, but propoxur and ethylan gave the most consistent and effective control. Most insecticides did not significantly reduce populations of spiders andM. atrolineatacompared with untreated checks, but they did reduce numbers ofC. lividipennis. Fifteen treatments caused resurgence ofN. lugens, resulting in significantly higher numbers in the treated plots than m untreated checks. Resurgence was apparently not caused by the toxicity of the materials against predators. Eleven of the insecticides had no effect onN. lugens.