Isolation of an agent affecting the development of an internal parasitoid

The development of an internal braconid parasitoid, Glyptapanteles militaris, is adversely affected when its host, Pseudaletia unipuncta, is infected with the Hawaiian strain of granulosis virus. A plasma-derived agent, isolated from virus-infected hosts, was shown to elicit developmental aberrations in the parasitoid similar to those observed in virus-infected hosts. This agent was isolated by ammonium sulfate precipitation, gel filtration, and anion exchange chromatography, and its molecular weight, established by gel filtration and SDS-polyacrylamide gel electrophoresis, was determined to be about 64,000. The dilution end point of the agent and some stability properties were also established.