Unfortunately all the wet weather we’ve been experiencing is bound to increase the risk of blight on potatoes and tomatoes in some areas. This nasty disease is caused by a fungus-like organism and I’m afraid that to date there is no cure.
It is a serious disease for both potatoes and outdoor tomatoes and spreads rapidly on the foliage and tubers of potatoes and on the fruit of tomatoes during periods of wet weather, causing them to decay and collapse. It is not as common but can still occur on greenhouse tomatoes.
First and foremost you need to be vigilant and if you spot the characteristic brown blotched leaves remove the foliage immediately. Late blight can devastate the foliage but if the tubers have set and tops are removed quickly the blight may not have transferred to the tubers and they can still be used.
Blight infections in gardens come from spores which originate in other gardens and allotments and are carried on the wind. Wet and warm conditions are perfect as spores cannot reproduce on dry leaves, so wet leaves are essential to the germinating process. Once this has happened in only a few days your crop can be spreading the disease to other plants and helping to infect other gardens!
Although there is no cure, there are preventative measures you can take, especially if you are in a high risk area. Fruit & Vegetable Disease Control is a traditional protective fungicide for the control of common fungal diseases affecting fruit and vegetable plants, including the control of blight in Tomatoes and Potatoes. Spray mid-June to mid-August at 10-14 day intervals while weather is warm and damp and hopefully this will keep your plants clean and healthy.