Tomato Ringspot Virus Disease
Tomato ringspot virus is vectored by the dagger nematode. This virus can infect many different species of plants, including other fruit crops such as apples, peaches, and raspberries, and weeds such as chickweed and dandelion. Infection spreads slowly.
Symptoms include leaves that are malformed and have circular chlorotic spots on them, 1/16 to 1/8 inch in diameter. In addition, stems, twigs, and branches may exhibit circular, brownish necrotic spots of similar size. Younger terminal leaves tend to be strap shaped and have a mottled pattern (alternating yellowish to greenish stippling). Fruit production may be reduced and infected plants may eventually die. One indication that the disease is spread by the dagger nematode is that symptoms spread slowly in a circular pattern at a rate of about 3 feet per year in all directions.
The best control for this virus is to test the soil for nematodes before planting and avoid following with fruit crops. Weeds, especially dandelion, serve as a reservoir for the nematode and should be controlled. Plant only virus-tested clean stock.