Abstract
The biological nature of three biotypes of the brown planthopper, Nilaparvata lugens, which possess differential abilities to infest resistant rice varieties, was comparatively studied with respect to their feeding effect on rice seedling growth, host preference response, honeydew excretion, embryonic and nymphal development, and fecundity. The three biotypes were most clearly distinguished from one another on the basis of their average honeydew excretion and the number of progeny produced on rice varieties with different major genes for resistance to this insect in spite of large quantitative variabilities in these physiological traits within each biotype population. In addition, biotype 3 differed significantly from the others, particularly from biotype 1, in its feeding effect on seedling growth, host preference, and nymphal development on resistant varieties. Biotype 3 was also found to be less fecund than others even on a susceptible variety.
