Pathogenicity of Entomophthora delphacis HORI to the brown planthopper, Nilaparvata lugeus (STAL)

Abstract

Infection experiments with Entomophthora delphacis on various stages, sexes, and wing forms of Nilaparvata lugens were carried out. The insects were put in small test tubes and inoculated with the conidia of this fungus discharged from culturing media for one night. The mean mortalities of macropterous male, macropterous female, brachypterous male, and brachypterous female were 19.8, 26.0, 0.0 and 2.4% respectively. The mean mortalities of 1st and 2nd instar, 3rd instar, and 4th and 5th instar nymph were 4.2, 2.9 and 22.0% respectively. The mortalities of brachypterous form and young nymph were significantly lower than those of macropterous form and old nymph. No significant difference in incubation period existed among stages, sexes and wing forms.