2 NOVEL VIRUSES ASSOCIATED WITH SEVERE DISEASE SYMPTOMS OF THE GREEN STINKBUG NEZARA-VIRIDULA

Two viruses were isolated from green stinkbugs (Nezara viridula) with severe disease symptoms. These viruses have been named N. viridula virus type 1 (NVV-1) and NVV-2 according to their relative sedimentation coefficients. NVV-1 is a small picorna-like virus with a diameter of 29 nm, a buoyant density in CsCl of 1.34 g/ml and a sedimentation coefficient of 153S. NVV-1 particles contain a 9.4 kb ssRNA segment and have three coat proteins of M(r)s 32 100, 31 500 and 30700. NVV-2 sediments as two components on sucrose gradients; the top 104S component consists almost entirely of 41 nm empty capsids and the faster sedimenting 177S component consists of intact 39 nm spherical particles. NVV-2 particles have a buoyant density in CsCl of 1-39 g/ml and consist of one major protein of M(r) 73 800 and at least two minor proteins of M(r)s 13500 and 16500. Only one dsRNA segment of 6.2 kb was identified. The properties of NVV-2 are similar to those of the Totiviridae. Individual stinkbugs were infected with either NVV-1 or NVV-2, or with a mixture of the two viruses. Re-infection of virus-free stinkbugs with the mixture resulted in typical disease symptoms. Both viruses were vertically transmitted through the eggs and insects were infected by surface contamination of their food source.