A granulosis virus of the tiger moth

JOURNAL

OF

INVERTEBRATE

PATHOLOGY

A Granulosis

20.

222 (1972)

Virus

of the

The caterpillars of the tiger moth, Dior~ycopus arnasis, are destructive to a variety of garden plants in the Western Province, South Africa. They are commonly found in the months of spring, and their bristles make them unattractive to predators. During late spring and summer the larvae die in large numbers. The cause of this high mortalit’y was thought to be a viral agent, and the following investigations

Tiger

Moth

were undertaken to ascertain whether the tiger moth harbored a virus. Dead and moribund larvae were placed in a beaker of water, cut up into small pieces, and the mixture was allowed to settle. Particles which settled under gravity were purified by filtration through cheese cloth followed by three cycles of differential centrifugation and treatment with fluorocarbon and ultrasonication. Granulosis capsules were obtained in this manner. They were sedimented at 15,000 g for 30 min and examined in an Elmiskop IA Siemenselectron microscope operating at 80 kV. The electron micrograph obtained is shown in Fig. 1. The granulosis capsules varied between 330 and 460 nm in length and 200 and 300 nm in width. Occasionally longer particles wore observed in the preparation. This work Department South Africa,

was financially of Agricultural to whom the

supported by the Technical Services, authors express their

gratitude. A. POLSOr; HELA GITA~

FIG. 1. Granulosis capsules isolated tiger moth caterpillar. Negatively

M.R.C. and U.C.T. Virus Research Unit Medical School Obsewatoly, Cape Town

from the stained.

Received January 26, 1972

X76,000.

Copyright All rights

Q 1972 by Academic Press, of reproduction in any form

Inc. reserved.

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