Tomato spotted wilt virus
A virus carried by thrips that causes bronze rings and spots on leaves and fruit and wilts tomatoes, peppers, lettuce and many flowers.
Also known as: TSWV, Spotted wilt
Symptoms and identification
Young leaves develop small dark brown or bronze spots, rings and streaks, then curl, yellow and die. Growing tips may wilt on one side and plants are stunted. Fruit show pale, ring-shaped markings that look like bullseyes and ripen unevenly.
Causes
The virus is spread only by thrips, which pick it up as young larvae feeding on infected plants and pass it on as adults for life. It lives in over 1,000 plant species, including weeds and ornamentals.
Organic treatment
Remove and bin infected plants straight away. Neem oil and insecticidal soap reduce thrips numbers but cannot save an infected plant.
Prevention
Control thrips and weeds, use blue or yellow sticky traps, and keep new plants separate until you are sure they are clean. Plant resistant varieties and use reflective mulch.
Chemical treatment (use with care)
No chemical cures a virus. Insecticides labelled for thrips may slow spread but do not stop all infections.