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Fourth instar larvae of the gypsy moth,Porthetria dispar (L.) were infected with the fungusConidiobolus coronatus(Cost.) Batko using the spore shower technique for varying periods of time. Larvae treated for more than 20 minutes showed 100% mortality. Virulence of the pathogen was increased by inoculating larvae of the wax moth,Galleria mellonella (L.) three times in serial succession. Typical symptoms of the infection were lightening of color, flaccidity, shrinking and finally desiccation of the larvae. Observations on the histopathology of infected larvae showed penetration of the integument by hyphae within 22 hours after inoculation and at 34 hours post inoculation, the hemocoel, head, nervous system and muscles were completely infected. A localized mycelial growth in the digestive system resulted probably due to the ingestion of spores, but penetration of the gut wall was not recorded.

Larvae of the gypsy mothPorthetria dispar (L.) were infected with sporulating cultures of the fungus,Entomophthora virulentaHall & Dunn using the spore shower technique. The infectivity of the parasite in the host and its histopathology was observed. Penetration of the integument was recorded at 24 hours post-inoculation and conidiophore production occurred at 72 hours after infection. Experiments on mammalian toxicity against laboratory mice showed no significant differences between control and treated mice in body weight, blood cell counts, food and liquid consumption and in the post-mortem examination.