Viruses—Potyviruses, Mosaic viruses, Cucumber aphidborne yellows, and Lettuce infectious yellows
Symptoms of virus diseases include mottling of light green, yellow, or white areas on leaves, clearing of veins, thickening of leaves, and reduction in growth and yield. Fruit may be deformed.
Viruses are transmitted by insects, such as aphids, whiteflies, and cucumber beetles. Remove infected plants as soon as they are detected. It is not practical to try to control virus diseases by using insecticides to control insects. Using reflective mulches may reduce or delay infections as it helps repel insects from plants. Covering young plants with row cover can also protect them from insects.
Watermelon mosaic virus on squash
Mottling caused by watermelon mosaic