Many horticultural crops belonging to the Solanaceae and Cucurbitaceae were seriously affected by virus diseases both in West Malaysia and the southern part of China. Five kinds of viruses, chilli veinal mottle virus (CVMV), tomato spotted wilt virus (TSWV), cucumber mosaic virus (CMV), tobacco mosaic virus (TMV) and tobacco leaf curl virus were isolated from chilli plants in West Malaysia, and six kinds of viruses, CVMV, a pepper strain of TMV, CMV, broad bean wilt virus, alfalfa mosaic virus and a new potyvirus were isolated from sweet pepper in China. Most of the tomato plants were also found to be infected with viruses such as TSWV, CMV and TMV both in West Malaysia and China. Three kinds of viruses from cucurbitaceous crops, cucumber, pumpkin and wax gourd, have been isolated, and zucchini yellow mosaic virus was found to cause the most serious damage to the production of the crops.
The effect of agricultural materials used for the cultural control of chilli viruses was tested in West Malaysia. When the seedlings grown under net cover were transplanted into the field, the incidence of virus diseases and damage to chilli were very low, compared with the seedlings grown under open conditions.