Abstract
Field censuses were made to clarify the difference in population processes of the green rice leafhopper, Nephotettix cincticeps UHLER, between Hokuriku and Tokai-Nisinippon districts of Japan. In the former district, the density of this species in rice paddies increased at an almost constant rate from the first invasion of adults to the harvesting stage and the highest density of adults was a peak not usually attained in the Tokai-Nisinippon district. In the latter location, on the other hand, the rate of increase was initially high but became near unity in mid-summer to autumn. There was no remarkable difference between densities of spiders in the two districts. Although these results are consistent with the results of analyses of pest-forecasting records published elsewhere, further studies are needed to learn whether the factor most responsible for the difference is genetic or environmental (including cultural practice).
