Activity of entomophthoran fungal isolates (Zygomycetes) against Nilaparvata lugens and Sogatodes orizicola (Homoptera: Delphacidae)

Abstract

A total of 48 isolates of three species of entomophthoran fungi ( Erynia delphacis, Erynia (Zoophthora) radicans, and an undescribed species of Entomophaga) were tested against adult Sogatodes orizicola and Nilaparvata lugens (Homoptera: Delphacidae). Only E. delphacis was infective to both insects, though S. orizicola was infected to some extent by all three pathogens. N. lugens was consistently less susceptible to these fungi, which exhibited longer incubation times in this insect. With one exception, fungi from non- N. lugens and, especially non-delphacid hosts, were not infective or only weakly infective to N. lugens; some of these isolates were moderately or strongly infective to S. orizicola, and one was the most infective to this insect, killing 91% of the sample. No consistent differences were found among planthopper morphs with regard to susceptibility to the fungi. However, macropterous males died significantly earlier than macropterous females which, in turn, died significantly earlier than brachypterous females.