![]() However, early cultivars are still genetically susceptible to the disease, so if weather conditions mean that the disease gets going early in the summer they could still be affected first-early cultivars) are more likely to escape infection, as levels of the disease tend to increase as summer progresses. Infected material should be deeply buried (below the depth of cultivation), consigned to the local council green waste collection or burned, rather than composted (see 'Biology' section, below)Įarthing up potatoes well provides some protection to the tubers from blight spores washed down into the soil from lesions on the leaves or stemsĮarly-harvested potatoes (e.g. Malvern Autumn Show - 27-29 September 2024. ![]() RHS Flower Show Tatton Park - 17-21 July 2024.RHS Hampton Court Palace Garden Festival - 2–7 July 2024.RHS Botanical Art and Photography Show - 14 June – 7 July 2024.You’ll want to have with you the next time you shop for tomato seeds or plants.įor more information on tomato diseases, read Disease-Resistant Tomatoes.Īrticle updated from one published on March 6, 2016. I suggest you print this list or put it on your smart phone. Many still offer more disease sensitive varieties than resistant ones (old plant habits die hard!), but pretty much all of them carry at least one or two late blight resistant tomato plants. If you’re not into growing tomatoes from seed, look for tomato plants resistant to late blight in local nurseries at planting-out time. Here are over 50 late blight-resistant tomatoes to choose from. ‘Mountain Magic’ is an example of a tomato with heirloom tomato taste and texture, but with resistance to late blight. Just buy and sow varieties that are resistant to the disease and follow normal tomato cultural directives (grow them in full sun, practice crop rotation, leave space for aeration, water the roots without moistening the leaves, etc.) and you ought to be able to get a bumper crop of disease-free tomatoes. Natural resistance to the new strains of the disease has been found in certain tomatoes, notably in wild species, and has been bred into garden varieties by the same old-fashioned methods our ancestors used to create heirloom tomatoes like ‘Brandywine’ (which is terribly susceptible to late blight, by the way). There are now, however, tomatoes with genetic resistance to late blight. Resistant Varieties The wild tomato Solanum pimpinellifolium was one of those used in developing new resistant tomatoes. Worse, just when the fruit is almost ripe, soft brown or black depressions form on it and it begins to rot. The disease rises successively upwards, affecting leaf after leaf. White cottony growths may appear under the affected leaves … if the air is humid. ![]() At first, brown marks appear on the lower leaves and grow quickly in size. Notably, it shows up in late summer (it’s not called “late blight” for nothing!). You can recognize late blight by its symptoms. In fact, in climates with fairly humid summers, where late blight is most prevalent, late blight of the tomato is now that plant’s most devastating disease. ![]() ![]() But the new strains that appeared, notably US-22 and US-23, are much more virulent than the older ones and particularly harmful to tomatoes. This is an old disease, the one that caused the Irish potato famine in the late 1840s (the same disease also attacks potatoes), and gardeners thought that the disease was pretty much under control, since most commonly grown potato and tomato varieties of the time had some resistance to the original strains. New strains of tomato late blight ( Phytophthora infestans) appeared out of Mexico, homeland of the tomato, in the late 1990s and, by 2010, had spread all over the world, taking both seed suppliers and gardeners by surprise. Tomatoes showing tell-tale symptoms of late blight. ![]()
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