Plant virus diseases in the Yemen Arab republic

Abstract

Abstract Many economically important crops in the Yemen Arab Republic were found to be affected by viruses in surveys made between 1985 and 1988. Alfalfa mosaic virus (AlfMV) was widespread in forage alfalfa and adjoining vegetable crops. Most commercial stocks of alfalfa seed were infected by AlfMV with seed transmission rates between 1% and 12%. Watermelon chlorotic stunt disease caused serious losses in watermelon, and papaya ringspot, zucchini yellow mosaic, watermelon mosaic 2 and melon rugose mosaic viruses were isolated from other cucurbits. Turnip mosaic virus (TuMV) was a serious problem in many brassica crops, some of which were also infected with cauliflower mosaic, cucumber mosaic (CMV) and broccoli necrotic yellows viruses. Potato virus Y and AlfMV were isolated from potato, tomato and peppers; tobacco mosaic from tomato and potato virus X from potato. Cowpea mild mottle virus was isolated from cowpea, groundnut and broadbean; lettuce mosaic from lettuce; clover yellow vein from broadbean; CMV from beet; AlfMV and TuMV from okra; leek yellow stripe and onion yellow dwarf (OYDV) from kurrat and OYDV from garlic. Maize mosaic (rhabdovirus) was common in maize and sorghum, and maize‐streak and barley yellow dwarf viruses were isolated from maize. Maize dwarf mosaic virus was isolated from sorghum. Prevention and control procedures are suggested for the most economically important of these viruses.