In a bad late-blight year, tomatoes often get infected just as the first fruits ripen. All you can do is pull the plants up and save all ripe and mature green fruit that look healthy. These tomatoes can be spread out in a warm, dry spot to ripen fully. But this is often a waste of time as it is very likely that fruit are already infected and that they will rot before they ripen. Don't despair! We have worked out a simple method to cure infected fruit, that is, to kill off the blight pathogen without damaging the tomato. See The Organic Grower, 11, Winter/Spring 2010, p31: No more green tomato chutney: how to cure blighted tomato fruit.
Essentially, green fruit with latent blight infection was incubated at 40C for at least 12h, then ripened at room temperature. Control fruit rotted before ripening but blight was eliminated from the treated fruit. Small quantities of fruit are easily treated in a chicken-egg incubator and some domestic ovens can be set to hold 40C (104F). An alternative is to use a water bath (fish tank?) and put fruit in polythene bags.
Higher temperatures for shorter times might be effective but tomato fruit might suffer some damage.
What kind of blight resistant spuds do we really want?
GM or conventional? Jonathan Jones of JIC on R4 BBC "Farming Today" asserts that his GM Desiree is the answer.
We already have conventionally bred, LB resistant varieties like Sarpos, so why isn't everyone growing them? The answer is largely that we lack funding to promote our seven Sarpo varieties. Our early introductions, Sarpo Mira and Axona were red skinned, high dry matter potatoes that we were told the industry does not want. But throw a lot of money and a certain red-haired celeb at a similar variety, Rooster (not blight resistant), the industry loves it and sales soar rapidly into the top ten. Anyone got a million to invest?
In the small UK horticulture market we have excellent acceptance with many thousands of growers coming back for more each year.
And the presenter implied that the GM resistance was better than Sarpo resistance. Maybe Jonathan should include Sarpo Mira in his trials as a resistant standard if he doesn't already.
We went to visit our seed crops in blighty Aberdaron on the Llyn peninsula on Friday after many weeks of solid blight-inducing weather. The crop was virtually blight-free and Gareth the farmer was smiling.
We already have conventionally bred, LB resistant varieties like Sarpos, so why isn't everyone growing them? The answer is largely that we lack funding to promote our seven Sarpo varieties. Our early introductions, Sarpo Mira and Axona were red skinned, high dry matter potatoes that we were told the industry does not want. But throw a lot of money and a certain red-haired celeb at a similar variety, Rooster (not blight resistant), the industry loves it and sales soar rapidly into the top ten. Anyone got a million to invest?
In the small UK horticulture market we have excellent acceptance with many thousands of growers coming back for more each year.
And the presenter implied that the GM resistance was better than Sarpo resistance. Maybe Jonathan should include Sarpo Mira in his trials as a resistant standard if he doesn't already.
Tenth Annual Open Day at Sarvari Research Trust
Friday 3 August at Henfaes Research Centre, LL33 0LB
Morning session at 10 for 10.30am: Potato Blight update/Sarpo varieties/Early blight update. Potato and tomato themed lunch. 2.00pm Tomato Blight research with ProVeg Ltd and Bangor University. Demo and trials of tomato in field and tunnel. Places still available - book now on 07 906 710704.
Morning session at 10 for 10.30am: Potato Blight update/Sarpo varieties/Early blight update. Potato and tomato themed lunch. 2.00pm Tomato Blight research with ProVeg Ltd and Bangor University. Demo and trials of tomato in field and tunnel. Places still available - book now on 07 906 710704.