Mosaic viruses of potato
Many viruses are difficult to distinguish from one another based on symptoms alone. In addition, for each particular disease, symptoms will vary greatly depending on stage of plant at time of infection and other factors. In general, virus symptoms consist of various leaf and plant deformities, stunting and poor growth, or yellowing or mosaic or mottling pattern in the leaves. Leaves may be crinkled or wavy. Dry, corky areas or necrotic streaks may be present. Identification of the particular pathogenic agent can only be made with serological, inoculation, or other laboratory tests.
Control weeds as some may serve as alternate hosts for virus. Buy and plant virus-free seed or seed tubers. Some varieties may show resistance. After symptoms on plants occur, there is no practical control. Reflective mulches or row covers may help prevent infection by aphid-transmitted viruses. Plants showing symptoms near harvest are edible.
Yellow mottling of alfalfa mosaic virus
Mosaic and yellowing of potato mosaic virus