Usually plants are stunted and partially defoliated depending on the stage of growth when infected. The leaves may become dry and brittle as they die exposing the vine to sun- burning. The secondary effects on fruit would be an increase in sunburning, premature ripening, poor flavour and texture. Older leaves are covered first with a dirty white fungus. Younger and inner leaves are at first spotted with mats of mycelium of the fungus which enlarge and join to form larger areas.
Spores develop on either side of the leaf.
Beet mosaic yellows virus increases the susceptibility of beets to powdery mildew. The fungus is first noticed on the upper sides of the leaves. In severe cases, the stems, petioles and pods may be covered as well, while the plant tissue below becomes reddish-brown and finally the leaves may turn yellow and drop off. Eradicate crucifer weeds and volunteer plants. Be sure to read labels carefully for their use on specific crops.