My daughter and her fiance have started an organic veggie garden, but the tomatoes have black rot and are covered with white flies. She doesn't want to use harsh chemicals. Any ideas please?
Dying tomato plants
Try this article for the whitefly: http://www.ipm.ucdavis.edu/PMG/r783301211.html
It's not clear from your post exactly which disease the "black rot" is--here's a link from that same website with a list of all the various tomato diseases so click on the ones you think it might be and it'll give you info on control http://www.ipm.ucdavis.edu/PMG/selectnewpest.tomatoes.html
Note that the website in both links is based on Integrated Pest Management, which is not the same thing as organic (although I actually like it better because I prefer when possible to not use any chemicals at all, not even organic ones). The principle is to employ cultural controls first (which would be organic), then if that won't work you move to the most friendly pesticide possible (often something organic) and then as a last resort heavier duty chemicals (which typically aren't organic). If you read through the articles they always have a section mentioning which controls are organically acceptable so if you want to stay organic you can, but make sure you read that section and don't assume that everything they mention is going to be organic.