Blight hits tomatoes, potatoes

LATE BLIGHT ¿ The leaf of a tomato plant withers and rots after it has been infected with the fungus that causes late blight in tomato plants. Cornell Cooperative Extension warns gardeners to watch for signs of the fungus which is killing plants and ruining gardeners tomato harvest.

WHITESTOWN — Tomato Late Blight has been discovered and confirmed in Onondaga County.

Officials with Cornell Cooperative Extension said there have so far been no reports of blight in Oneida County, Consumer Horticulture Program Assistant Lynette S. Kay said.

Late blight is a highly contagious airborne disease that caused the Great Potato Famine in the 1800s and wiped out much of 2009’s tomato crop. The cool, damp weather that year provided the perfect environment for the disease to take hold and spread quickly, Kay said.

To see where Tomato Blight has been found look at the link: According to the site’s USAblight map, cases have been identified in Suffolk, Allegany, Chenango, Clinton, Dutchess, Putnam, Tompkins and Washington counties this summer as well.

Late blight does not survive in the soil. It can however, over-winter on diseased potatoes that may have been left in the ground or fresh spores can stick to clothing, hands or tools.

Large quarter size spots may appear on the leaves or the stems. Infected plants may look fine one day and be dead three days later. Once the disease takes hold there is no cure.
To prevent infection, start spraying with fungicides containing the chemical Chlorothalonil. Follow the manufacturer’s suggestions for rates and frequency. Organic products containing copper have not proven to be highly effective against Late Blight, Kay said.

Immediate attention is required for those with plants that have suffered blight. To prevent the spread of the disease, all plants and tomatoes should be bagged and sent to the landfill. Do not compost or burn — that would release the spores into the air causing greater contamination.

Anyone who suspects having Late Blight should not take infected plant parts to local nurseries because that could contaminate their crops. Instead place infected plant parts in a sealed plastic bag and bring them to the Oneida County Cooperative Extension, 121 Second St. For more information, go to CCE’s Home & Garden website at