ALTERNATIVE ROUTES FOR THE HORIZONTAL TRANSMISSION OF A NUCLEOPOLYHEDROVIRUS

Two alternative routes for nucleopolyhedrovirus transmission were inve stigated using Mamestra brassicae larvae: cannibalism of infected larv ae and the release of virus prior to the death of the diseased host. T he low frequency of cannibalism observed suggests that this is not a r elevant transmission route in this species. However, larvae were shown to transfer viable virus to the environment before death through eith er defecation or regurgitation. Over 40% mortality was observed in lar vae reared in diet containers where infected hosts had previously fed. Virus transfer to cabbages also occurred before death of the infected host, as revealed by plant bioassay. Virus was not detected in the fe ces or regurgitate of diseased larvae until the late stages of infecti on. (C) 1996 Academic Press, Inc.