Abstract
Polyhedra of a nuclear-polyhedrosis virus of the fall webworm, Hyphantria cunea, were recovered from soil which had been artificially contaminated with the virus. The purification procedure was as follows. The contaminated soil was suspended in 0.1M sodium pyrophosphate to detach the adsorbed polyhedra and incorporated into an aqueous two-phase separation system consisting of dextran (δ=0.694dl/g) and polyethylene glycol 6, 000. The detached polyhedra entered the upper phase, while the larger soil particles entered the lower phase. The recovery rate of polyhedra in the upper phase was high when the composition of the biphasic system was near the binodial. The rate decreased with an increase in the amount of soil incorporated into the biphasic system but did not decrease very much when the degree of virus contamination was decreased. With the application of the same purification procedure, polyhedra of a nuclearpolyhedrosis virus of the fall webworm were recovered from soil in an area where the virus disease had occurred naturally in host populations. Indirect fluorescent antibody technique and staining with Buffalo black were used for the microscopical identification of the recovered polyhedra.
