Genetic variability of four natural isolates of the Stilpnotia salicis multiple-enveloped nuclear polyhedrosis virus.

Viral genome DNA from four different multiple-enveloped nuclear polyhedrosis virus isolates, obtained from naturally infected larvae of satin moth (Stilpnotia salicis), a pest of poplar tree (Populus) was analysed. Larvae were collected over a period of 11 years, from 1978 to 1989. The genomic DNA restriction patterns pointed to heterogeneity of these wild-type viruses. The differences observed in isolates of several years revealed limited restriction fragment length polymorphism and showed that these viruses contained distinct, but closely related genotypes. The genome size of SsMNPV was established as 128-134 kb, based on HindIII and SacI restriction analysis.