Effects of tungro virus-infected rice plants on the behavior and biology of the vectorNephotettix virescens(Distant) were investigated. In a choice test, tungro-infected plants attracted significantly moreN. virescensindividuals than did healthy plants, but after 24 h more individuals settled on healthy plants. Insect feeding on diseased plants was disrupted and the quantity of food ingested and assimilated was significantly less than on healthy plants. Although there was no significant difference in the number of nymphs that became adults on infected and healthy plants, the growth period was prolonged on diseased plants. A significant reduction in adult longevity, fecundity, egg hatchability, and population growth was observed on tungro-infected plants. However, oviposition was not affected. Tungro-infected plants had a significantly higher free sugar content but soluble protein was significantly lower than in healthy plants.