Tomato blight

Symptoms

Ripening tomatoes develop brown sunken spots, which spread to the leaves and stems.

Find it on: tomatoes

Time to act: summer

Problem categories

Overview

Tomato blight, a fungal infection called Phytophthora infestans, spreads by wind and water-splash. It also attacks potatoes, and is triggered by warm, wet conditions, making outdoor tomatoes more susceptible than those in a greenhouse. The crop is quickly ruined, and even if it's immediately picked you can't stop the tomatoes rotting.

Solution

Ripening tomatoes develop brown sunken spots, which spread to the leaves and stems.

Organic

Remove blight-infected plants as soon as they are identified, to prevent spread to other plants.

Chemical

Carry out repeated, preventative spraying the moment the first batch of tomatoes starts to set. Use fungicide containing copper. They don't provide 100 per cent protection, but an attack will be slowed down and you should get ripe tomatoes.

Discuss this problem

Talkback: Tomato blight

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jogriff 24/11/2011 at 15:27

very useful info - thanx

sedwards 24/11/2011 at 15:27

I have been informed that once I have had this tomato infection I cannot grow tomatoes for seven years, is this true?

mluk25 24/11/2011 at 15:27

didnt find an answer to the question as to whether the tomato blight area of last year has to wait 7 years before being planted again

campervangran 24/11/2011 at 15:28

On Friday's Gardeners World, Joe Swift talked to a fellow allotment holder who sprayed his tomatoes against blight with potassium sulphate and lime. No more details - can anyone enlighten PLEASE? Lost all mine overnight!

rockandroll61 24/11/2011 at 15:28

regarding tomato blight, I have just lost all mine this week for the third year in a row. First two years in the greenhouse, this year outside. Perhaps the seven year rule is correct. Any ideas? Have taken the usual precautions with cleanliness etc.

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