Tomato blight is an infection caused by the fungus, Phytophthora infestans. Also affecting potatoes, blight is spread by wind and water-splash, and is particularly prevalent in warm, wet weather.
To prevent the frustration of losing your crop of tomatoes to tomato blight, it’s worth taking some simple steps to avoid it. Plants grown outside are more susceptible to infection, so you could also try growing tomatoes in a greenhouse, or grow blight-resistant varieties – there are plenty out there to try.
Follow our five simple tips to avoid losing your crop to tomato blight.
Keep them dry
Keep tomatoes dry – use an umbrella of polythene or a plastic roof over tomatoes planted outdoors to keep the rain off them.
Tucking tomato plants under a plastic tunnel
Provide good ventilation
Make sure there is good ventilation around the plants – keep the sides of any cover open and try to prevent condensation building up. Thin out some branches of vigorous bush varieties and remove weeds to allow air to circulate better.
Thinning a branch out of a tomato plant
Plant early to try for a harvest before late blight hits. Do not plant near potato crops that are susceptible to blight.
Planting up/out a small tomato plant
Choose resistant varieties
Choose a good resistant variety, such as ‘Losetto’ or ‘Lizzano’.
Ripe cherry tomatoes, ready to pick
Practice good hygiene
Destroy blighted foliage to reduce chances of infection. Don’t leave potato tubers in the ground at harvest as they could harbour blight. Blighted foliage can be composted away from the crop as spores need a living host to survive for more than a few weeks.
A blighted tomato crop
Grow early ripening varieties
Cherry tomatoes tend to be less likely to catch blight than beefsteaks, because they ripen earlier and are often harvested before blight hits.