ABNORMAL-BEHAVIOR OF THE COMMON ARMYWORM PSEUDALETIA-SEPARATA (WALKER) (LEPIDOPTERA, NOCTUIDAE) LARVAE INFECTED WITH AN ENTOMOGENOUS FUNGUS, ENTOMOPHAGA-AULICAE, AND A NUCLEAR POLYHEDROSIS-VIRUS

Daily migrational patterns of Pseudaletia separata (WALKER) larvae infected with Entomophaga aulicae and the nuclear polyhedrosis virus (PsNPV) were examined under laboratory conditions and compared to that of healthy larvae. The healthy larvae exhibited a daily rhythmic pattern of movement, i.e., feeding and movement on feeding plants at night and hiding them under the soil during the day through the 5th and 6th larval instars. When infected with either E. aulicae or PsNPV, the pattern of the movement was disturbed: the larvae crawled out from the soil even during the day and died near the top of the feeding plant. The symptoms first appeared two to three days and two days before the death in E. aulicae- and PsNPV-infected larvae, respectively. In the case of E. aulicae-infected larvae, a frequent vertical migration was observed during this period.