Insecticide Susceptibility and Wing-Form Ratio of the Brown Planthopper, Nilaparvata lugens (StÅl) (Hemiptera: Delphacidae) and the White Backed Planthopper, Sogatella furcifera (Horvath) (Hemiptera: Delphacidae) of Southeast Asia

Abstract

The brown planthopper and the white backed planthopper collected from Thailand and Philippines were considerably more susceptible to 8 insecticides, especially to DDT than those of Japan. Furthermore, they produced significantly higher percentages of brachypterous form than the Japanese strains when reared on rice seedlings. One of the two strains of the brown planthopper collected from Taiwan was quite similar to the Japanese strain with respect to insecticide susceptibility and wing-form ratio, and the other showed a coasid-erably higher DDT-susceptibility and a higher percentage of brachypterous form. These results suggested that the tropical populations of the two species of rice planthoppers are differentiated in physiological and ecological properties from the temperate populations. © 1980, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.