[mor_rigan]

My tomatoes are growing in a polytunnel but they developed blight nonetheless. Apparently there's a new strain around (blue 31) or something. I've cut away all the infected stalks and fruit. I've chopped off the tops of the plants. Hoping they'll make a comeback.



But I fear they'll be lost

I heard that there's a sort of incense one can burn in the polytunnel to get rid of the blight at the end of the harvest so it won't lie dormant in the soil. Any idea what that might be?

Are there any organic means of blight prevention and/or control?

[michael brenock]

polytunnel provides the ideal atmosphere for potato blight to spread once it arrives there. The spore or spores were carried by the wind from a nearby infected potato or tomato. A copper based spray is about the best prevention. But even with blight on the leaves you can still get a reasonable crop of fruit. All is not lost, at least the fruit stays firm even if it is black.
michael brenock horticultural advisor (retired)

[mor_rigan]

I have sprayed them now. But I didn't know black fruit would be ripen anyway.

Thanks very much!