So many diseases can ruin tomatoes that it is a wonder they are among the most widely grown vegetables. Fusarium and Verticillium wilts, early and late blights, tobacco mosaic virus and Stemphylium grey leaf spot are all caused by fungal or viral pathogens that travel through ground or on the end. Several equally dangerous diseases are spread by a bug known as the beet leafhopper (Circulifer tenellus).
Leafhoppers
Beet leafhoppers lay eggs in open fields during cool, moist spring weather. Nymphs feed for a couple of months and develop to light green bugs, wider in the head than in the tail, but only about 1/10 to 1/8 inch long. Adult leafhoppers live just about 30 days, but migrate over long distances, landing in fields and strayed from plant to plant on long back legs. In California, beet leafhoppers produce several generations. They overwinter and lay eggs in foothill areas.
Curly Top
Leafhoppers get viral pathogens by feeding in affected regions and act as carriers of the disease. Curly top is just a group of diseases (curtoviruses) containing beet curly top virus, beet mild curly top virus and beet severe curly top virus. New strains of the light virus also have been identified by University of California at Davis researchers working with pepper plants inn Mexico. Although beets and other plants in the Chenopodiaceae family are the preferred targets, leafhoppers will resort to sampling tomatoes and other plants in the Solanaceae family. They feed on plants by piercing fresh leaf surfaces and sucking on plant fluids during long mouthparts on their heads, inoculating the plant with the virus since they feed. Affected leaves curl inward and disappear. Veins may appear as purple lines or the entire leaf may change color. Since the leafhoppers begin with tender new development, the disease spreads in the top of the plant, hence the title curly top.
Tomato Big Bud
Tomato big bud is brought on by a viresent agent transported, or vectored, by the beet leafhopper. The disease is brought on by a phytoplasma organism to a wide range of crops. Buds swell and produce small, misshapen fruit. Leaves are distorted and pale yellow-green in color, on stunted stems. Major bud but isn’t common in most regions since it takes large populations of leafhoppers to acquire a foothold in areas so succeeding generations can feed on affected plants.
Leafhopper Control
Rumors might not function as leafhoppers’ favorite targets, but it just takes one wayward, hungry leafhopper to spread disorder to a plant. One option for handling where leafhopper populations increase in late spring, might be to plant tomatoes far away from favored plants like beets, peppers and eggplant. Where leafhoppers are present but backyard space is limited, companion planting marigolds (Tagetes spp.) Or pungent plants, such as geraniums (Pelargonium spp.) , might repel the bugs. In rainy years, when leafhopper residents mushroom, systemic pesticides containing carbaryl, imidacloprid or dinotefuran may help control residents.
