JOHN J. HAMM, ELOISE L. STYER, AND W. JOE LEWIS Three Viruses Found in the Braconid Parasitoid Microplitis croceipes and Their Implications in Biological Control Programs
BIOLOGICAL CONTROL 2, 329 .'336 (1992

Productivity and longevity decreased in a laborator colony of the parasitoid wasp Microplitis croceipe
(Cresson) (Hymenoptera: Braconidae). Using light microscopy, it was determined that the colony was free o microsporidia. However, samples of the colony examined for pathogens by electron microscopy revealed
three types of viruses: a nonpathogenic polydnavirus which is produced by all female wasps; a nonoccluded
baculovirus which is pathogenic to late-stage pupae and adults; and a picorna-like virus which is present in larvae, pupae, and adults. The nonoccluded baculovirus was eliminated from the laboratory colony of M. croceipes by selection of progeny from wasps which had oviposited within 2 to 3 days after emergence from the cocoons and which had lived for at least 14 days post- emergence. Upon death, the wasps were examined by negative stain electron microscopy and only progeny from baculovirus-free wasps were retained. Parasitoid colonies should be systematically examined for pathgenic viruses that may reduce their productivity and efflcacy as biological control agents. In addition, exotic parasitoids and predators should be evaluated for viruses and other pathogens while in quarantine.