Population Characteristics of the Brown Planthopper, Nilaparvata lugens (Hemiptera: Delphacidae), with Special Reference to Differences in Japan and the Tropics

Abstract

Light trap records showed that N. lugens, an important insect rice pest is prevalent in southwestern Japan. Adult female populations which were studied in Zentsuji, Japan, developed from sparsely distributed colonizers and then multiplied approximately 10-fold each generation. In Kalugomuwa, Sri Lanka, N. lugens populations never explosively increased. Population stability seemed to be associated with production of many macropterous females. In Indonesia, serious damage was usually observed in rice at the maximum tiller stage. Populations in some infested fields had many macropterous females. In contrast to field-wide injury in Indonesia, the Japanese N. lugens caused large patches of damaged plants. The formation of patches is explained on the basis of earlier population processes. The relation of mean crowding of N. lugens adult females to mean density was so complicated that their spatial distribution patterns could not always be explained by existing mathematical models.