I had always grown Shirley tomatoes very successfully in a tunnel but last year my sister grew Moneymaker tomatoes and they developed a disease whereby shoots became mouldy and died back. This year the shirley tomatoes had it as well and a lot of the shoots died back early. i don’t know what tis disease s. I had assumed that shirley tomatoes were disease resistant. How do I clean up the tunnel to get rid of this disease?
It is most likely to have been grey mould stem rot, due to botrytis fungus which was common this summer in a dull cool year, especially if the greenhouse was damp.
Remove all plant debris and try to keep the greenhouse well aired and dry during spring and summer cold and dull weather.