If there’s one word that strikes fear into tomato growers, it has to be “blight”. More people seem to be looking on the internet trying to see if they have blight than almost any other problem. The reason is simple, if you get late blight, it’s simple to spread throughout your whole crop, it will quickly destroy your plants and infect your fruit and there isn’t a lot you can do about it.
Blight is caused by Phytophthora Infestans and spreads rapidly in warm damp conditions. Whilst relatively common in outdoor tomatoes, especially when grown at allotments near to potatoes, it is less common in greenhouses because it tends to be spread on damp leaves.
Early Blight is a different problem, caused by Alternaria solani And, whilst relatively common in the US, is less so in the UK but is becoming more common. Fortunately, Early Blight is less aggressive and if you cut off and destroy affected leaves may not affect the crop too much.
My interest in Early Blight has been sparked by the fact that (I think) it has struck this year on one of my plants. What’s interesting about the plant it has struck is that it has been grown from seed I saved from Mountain Magic, an F1 hybrid which is supposedly Blight Resistant. Now I realise that The saved seed will not have inherited all the Blight resistance of the F1 hybrid but the parents were chosen because of their resistance. The plants I have grown are very different from each other (some are potato leafed and some are regular leafed). The plant affected is regular leafed and I would love to know whether the original parents were different leaf types or whether I’ve got something different again.
Anyway, I have cut off the affected leaves and will keep an eye on the plants and decide whether to take them out if they get worse.