Posted: 15/11/2012 at 11:18
Sorry, Catherine, I didn't see any specific reference to Late Blight in terms of your article. It just says "tomato blight".
Anyway, Late Blight is no different to any of the other fungal diseases in the way it is transmitted. It's just a different pathogen. The only difference is the ugliness of the outcome. So, in terms of prevention or minimisation of the effects, anything relevant to fungal diseases in general relates to Late Blight.
Well, let me clarify that. The traditional preventive sprays - copper-based - can be effective against the common fungal infections but much less so against Late Blight. The other fundamental difference, of course, is Late Blight's destructive properties. It can destroy a plant within a week so there's usually little that can be done to save the plant once infected. Dove [posting above] had all the classic symptoms of Late Blight but managed to save her plants. A triumph of tomato care!
I'm sorry but the RHS is promolgating a furphy. Toms in greenhouses are not less likely to suffer Late Blight. If the pathogen is around, the plants - outdoors or in a greenhouse - can be affected, and the greenhouse incubator effects I mentioned earlier can and will come into play. I'm sure Monty Don isn't the only one who will question the RHS' advice.