There are two common diseases that get on tomatoes every year - early blight and septoria leaf spot. These are troublesome and in some years they can really reduce your yield, but they're something we can live with.
Late blight is a different story. This fungus disease affects tomatoes and potatoes and is seen only rarely this far north. It doesn't survive our winters so it either blows in or is carried in on infested plants. We haven't seen late blight in area since one summer in the late 1990s.
Unfortunately, late blight is here now. We're asking anyone growing tomatoes or potatoes to be on the lookout. As soon as you notice any large, brown patches on your plant leaves or stems, please bring a sample to any Cornell Cooperative Extension office. Enclose it in a plastic bag and keep refrigerated if possible.
This disease affects tomatoes, potatoes. It spreads very rapidly and will quickly jump from one garden to the neighbors. The brown patches produce lots of spores that are blown by the wind and carried by rain. If one gardener ignores the problem and leaves their plants to die they could become the source for a widespread infection. While a home garden can lose a few tomato plants, our growers with hundreds of plants will be severely affected by this disease.
Infested plants need to be removed from the garden in a plastic bag, don't try composting them or leave them in a pile.
For more information about late blight visit www.hort.cornell.edu/lateblight or call our office for a fact sheet.
Thanks for keeping your eye out for this disease as we try to minimize its impact.
Amy Ivy is executive director of Cornell Cooperative Extension in Clinton County. Cornell Cooperative Extension offices may be reached in Clinton County at 561-7450, and Essex County, 962-4810. More information may be found on-line at http://ecgardening.cce.cornell.edu or by sending an e-mail to a Master Gardener volunteer at askMG@cornell.edu.