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Adam Pasco writes about harvesting outdoor tomatoes longer than anyone else”

Could this be the first year in decades when I can grow tasty tomatoes outside without the risk of losing the whole crop to blight?

Well, a groundbreaking new tomato is available for the first time in 2015, and my hopes are high that at long last I’ll be able to enjoy growing tomatoes outside on my plot rather than just in the greenhouse.

As some will know, our hopes have been raised many times in the past, with several new tomato introductions in recent years claiming to offer some tolerance to blight disease … and I stress the word ‘tolerance’ here and NOT resistance.

I’ve tried growing most of these, and several blight tolerant varieties are still listed in seed catalogues including ‘Ferline’, ‘Fandango’, ‘Fantasio’, ‘Legend’, ‘Losetto’, ‘Koralik’ and ‘Lizzano’. Some have performed reasonably well in ‘low blight’ years, but all have succumbed to the disease by high summer with the consequential loss of crop.

Now we have news of what Suttons Seeds claim is “the World’s first fully blight resistant tomato” … a variety called ‘Crimson Crush’.

I haven’t tasted ‘Crimson Crush’ yet, but it’s described as a producing ‘great yields of fine tasting, large, round tomatoes – each weighing up to 200g.

Supporting their claim, Suttons provide some technical details of this plant breeding breakthrough. ‘Crimson Crush’ contains two special genes in its genetic makeup, called PH2 and PH3.

To the uninformed, like me, blight is blight, but this fungus mutates and changes to produce different strains of blight. Two of these strains are called ‘Pink 6’ and ‘Blue 13’ – strains that have really decimated outdoor tomato crops in the last few years – and the genetic makeup of ‘Crimson Crush’ provides resistance to both of these strains of blight.

But for how long will this resistance last?

If, as we know, the blight fungus regularly mutates to form new strains of blight then perhaps a new strain will evolve that will attack and infect this new tomato! Perhaps it’s only a matter of time, but for now I’m certainly going to grow ‘Crimson Crush’ outdoors, as it has specifically been bred for outdoor growing, and will enjoy a disease-free crop for as long as possible.

One of the most compelling reasons to grow your own tomatoes is choosing varieties for flavor, and regularly topping the charts for the best flavoured tomatoes are ‘Gardener’s Delight’ and ‘Sungold’. I’ll still be growing these, but in the warmth and protection of my greenhouse where blight disease very rarely causes a problem.

THE BACKGROUND STORY TO ‘CRIMSON CRUSH’

Tomato Crimson Crush	 Suttons

And now a little background information. ‘Crimson Crush’ is the result of a plant breeding programme being carried out by experienced breeder Simon Crawford and James Stroud, a PhD student at Bangor University. Simon has an excellent track record in breeding tomatoes, breeding the groundbreaking outdoor bush variety ‘Red Alert’ several years ago.

‘Crimson Crush’ is the result of conventional plant breeding and NOT a genetically modified variety. UK exclusive selling rights have been granted to Suttons Seeds who are only selling seedlings in 2015, and not tomato seeds.

BLIGHT DISEASE AND ITS CONTROL

The blight disease that attacks tomatoes is the same disease that infects potatoes, and it’s a period of warm and very humid weather that encourages the fungus to spread through the air. Airborne spores landing on leaves of potatoes or tomatoes then have perfect conditions and moisture to germinate and infect their host.

The loss of effective garden chemicals has exacerbated the problem, as a useful fungicide called Dithane 945 that contained the active ingredient Mancozeb is no longer available to home gardeners.

Murphy also withdrew their Traditional Copper Fungicide in 2009, I believe, but it has since been replaced by Bayer Garden with Fruit & Vegetable Disease Control, containing Copper Oxychloride.

This fungicide needs to be applied as a barrier, coating leaves with the chemical before any disease spores land on them. However, the chemical is washed off by rain, and despite thorough and regular re-application to all leaf surfaces with a pressure sprayer I’ve never found it provides satisfactory protection.

Potato growers can now choose resistant varieties from the ‘Sarpo’ range, and my hopes are high that ‘Crimson Crush’ will provide a blight-free future for tomato growers too.

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