ChileanJAR

Tobacco plantings in Chile are being severely affected by a virus disease, commonly named “necrosis severa”. Symptoms are characterized by the development of vein clearing, chlorotic mottling, mosaic, leaf puckering and veinal necrosis. Necrotic lesions on midribs and stems, eventually extending into the pith, usually develop on affected plants. A severe leaf distortion, stunting, and death are frequently found among diseased plants. Evidences for the presence of potato virus Y (PVY), potato virus X (PVX) and cucumber mosaic virus (CMV) were found. Belief that PVY is involved as a causal agent of “necrosis severa” is based on the observation of rodshaped and flexous viral particles of 680-710 nm in length and of Pinwheels, inclusion bodies, on diseased cells, and on the occurrence of local lesions on Solanum demissum X S. tuberosum (Hybrid A-6). Similarly, the presence of cristalline inclusion bodies, composed of isometric viral like particles of 25-30 nm, on diseased cells, systemic symptoms on Cucumis sativus ‘National Pickling’, C. melo and Cucurbita pepo, and local lesions on Vigna sinensis, suggested the presence of CMV. Finally, symptoms on Gomphrena globosa and Chenopodium amaranticolor and the presence of rod-shaped and flexous viral particles of 500-530 nm in length, suggested the presence of PVX on affected plants. These results were serologically corroborated.