Tomato spotted wilt virus: how to recognise and treat it

Disease

Symptoms

Young leaves with a bronze cast that later show small dark brown spots; leaves may cup or roll.
Dark brown streaks on stems and leaf stalks; tips die back, and plants are stunted or grow lopsided.
Fruit with pale yellow or light green rings, often raised in the centre; ripe tomatoes blotched red and yellow; peppers with ring spots.
Plants infected young often fail to flower or set fruit. There is no cure once a plant is infected.

Remove and destroy infected plants as soon as you see symptoms, especially those infected before fruit set — they will not recover and feed new thrips with the virus.
Cover young plants with fine-mesh row covers from planting — the most effective way to keep virus-carrying thrips off.
While plants are small, reflective mulch repels flying thrips and delays infection.
Protect thrips predators such as minute pirate bugs, lacewings and predatory mites by avoiding persistent insecticides; insecticidal soap, oils or pyrethrins give only short control.

Spinosad against thrips, following the label; insecticides seldom kill thrips fast enough to stop the virus spreading, so prevention matters more.

Reference information, not a guarantee. Read and follow the label of any product: dose, safety and the days to wait before harvest.

Grow resistant varieties — tomatoes with the Sw-5 gene, peppers with Tsw.
Buy healthy transplants; reject plants with ring spots, streaks or off-colour leaves.
Control weeds in and around the garden — they harbour both the virus and thrips; clear old crops after harvest.
Watch for thrips with yellow or blue sticky traps, and avoid planting tomatoes next to peppers or susceptible flowers.

Figures checked against these sources.