Severe infection can result in the complete failure of the crop. There are no effective means of control. The virus overwinters in perennial weeds and is transmitted from weeds to healthy plants in the fields by aphids. Environmental conditions favoring aphid multiplication and migration into the field will result in severe outbreaks of the disease. Keeping fields clean of weeds around the edges and turnrows and controlling insects may help in reducing spread of the disease.
Resistant varieties are now available in limited supply.
Check with your county Extension agent on currently used varieties. Small, angular, brown spots with concentric rings occur on lower leaves. Several spots may run together and kill the leaf. Control through the use of fungicides is suggested. Large, watersoaked areas on leaves and stems.