Abstract: The interactive effects of Nilaparvata lugens and Sogatella furcifera in their commensality were studied with nylon net method. The results indicated that within 96 hours, the rest rates of these two kinds of insects on rice plants were gradually increased with time, finally reaching 21.5～25.0%, and there was no difference from each other. In pulse experiment, the female ratio and brachyptery of Sogatella furcifera were increased by 22.1 and 398.1%, and in removal experiment, the reproduction, female ratio and brachyptery of Sogatella furcifera were decreed by 8.8, 20.8 and 48.0%, respectively. Positive or negative effect of the interaction on reproduction, sex ratio and wing-form was observed and meaning and pattern of the interaction were also discussed in this paper.

Key words: Nilaparvata lugens, Sogatella furcifera, Commensalism, Interactive effect, nitrogen, competition index, rice, intercropping, silicon, water spinach