If there is a special gardening topic you would like more info about email patty@pattysplants and she will post it here.
What You Need to Know About Tomato Blight
Late blight, caused by the fungus Phytophthora infestans, is a very destructive and very infectious disease that killed tomato and potato plants in gardens and on commercial farms throughout the mid-west and eastern U.S. during 2009. The cool, wet growing season contributed to last years disastrous tomato troubles.
Tomatoes. Late blight is not seedborne (however, it is tuber-borne in potato), so tomato plants started from seed locally should be free of the disease. Growing your own transplants from seed or purchasing from a reputable local grower will ensure a healthy start to the season. In addition to late blight, each year tomatoes become infected with early blight and Septoria leaf spot, which look very similar.
Potatoes that freeze or fully decompose will not carry the pathogen over winter. Tomatoes will not carry late blight over the winter, because freezing kills the whole plant. Tomato seed, even from fruit that was infected with late blight, will not carry the pathogen, so no need to worry about the tomatoes left behind in the garden or compost pile. Certain perennial weeds can become infected with late blight, but none of their above-ground tissues live through the winter. Late blight will not survive on tomato stakes and cages.
The biggest threat for overwintered disease is on potatoes. In the spring, advise home gardeners to inspect last year’s potato plot and any compost or cull piles for volunteer potato plants that might come up. If potato plants are found, pull them out and put them in the trash or destroy them. If tubers were infected and survive, then the late blight could grow upward from the tuber, infecting the stem and producing spores when weather conditions are favorable. These spores could then disperse to other tomato and potato plants.
Source: Tina Smith outreach educator, UMass Extension, Amherst
Pictures and More Info on Late Blight: