A number of my tomatoes have developed some sort of fungus, the leaves have
started to change colour and some of the fruit are covered with fine white
stuff, I have dug themall out and put them in the dustbin rather than on the
compost heap.

Last year I bought some tom plants from a car boot and they suffered from
the same problem, which spread to the plants I had grown from seed, the toms
in the greenhouse were fine, although when I stopped watering them the
leaves there started to go a funny colour, which I put down to the fact that
they were dying off anyway.

So what is the answer to this problem?

I don't want to lose the chance of growing my own, I much prefer them to the
rubbish which is on sale in supermarkets.

Alan