Canadian Forest Service Publications
Infection and mortality of spruce budworm, Choristoneura fumiferana, and forest tent caterpillar,Malacosoma disstria, caused by nuclear and cytoplasmic polydedrosis viruses. 1969. Bird, F.T. The Canadian Entomologist. 101:1269-1285.
Issued by: Great Lakes Forestry Centre
Catalog ID: 34332
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Cytoplasmic polyhcdrosis viruses are in general, more infectious to spruce budworm, Choristoneura fumiferana (Clemens), and forest tent caterpillar, Malacosoma disstria (Huber)than the nuclear polyhedrosis viruses which affect these insects. The cytoplasmic polyhedrosis viruses interfere with and retard development of the nuclear polyhcdrosis viruses. Larvae of both insects, as they grow older, develop resistance to both viruses. Resistance develops more rapidly and to a greater degree against the nuclear polyhedrosis than against the cyctoplasmic polyhedrosis viruses, The nuclear polyhedrosis ,viruses are more lethal than the cytoplasmic polyhedrosis viruses, and all larvae infected with the nuclear polyhedrosis viruses die except those infected so late in larval development that they are able to pupate. Most young larvae infected with the cytoplasmic polyhcdrosis virus die or :are seriously affected, but infection has progressively less effect as the larvae mature.