North Country home gardeners and commercial growers are being warned of the potential for late blight this growing season.

Late blight is a plant disease that causes tomato and potato plants, primarily, to wilt and die. It spreads rapidly from plant to plant in wet, cool weather.

“The exceptionally cool, damp spring we are experiencing throughout New York State this year heightens our concern for late blight,” said New York State Agriculture Commissioner Darrel J. Aubertine.

The commissioner said he wanted to alert home gardeners and commercial growers to the potential introduction of late blight this growing season.

“We saw the devastation it can do to a tomato crop in 2009, and we have already received reports of early late blight detection in neighboring states,” Aubertine said. “Therefore, we want to remind our growers of this possible plant disease and alert them of the precautions they can take and how we, as a regulatory agency, are working to protect our plants.”

Last year, the Department of Agriculture and Markets upgraded the State’s detection and eradication efforts by additional training for its horticultural inspectors, surveying plants at the retail level and in commercial greenhouses, and working with Cornell Cooperative Extension to conduct outreach and followup in the field with growers and gardeners.

This year, the commissioner says inspection of tomato plants has been a priority, and to date, more than 150,000 tomato plants have been inspected with no signs of late blight so far.

The department has also been in regular communication with neighboring states and county Cooperative Extension offices. Just recently, the department learned of two localized outbreaks, one on “volunteer” tomatoes in a greenhouse in Maine where they had problems with the disease in previous years, and one in a Connecticut greenhouse on potatoes and tomatoes where the blight was likely on the cut seed potatoes.

If late blight is detected in New York, the suspect lot of plants will be subject to quarantine upon initial visible diagnosis by a state horticultural inspector and the product sample will be sent to the Plant Disease Diagnostic Clinic at Cornell University for confirmation. If confirmed with late blight, the plants will be properly disposed of under state supervision and an investigation will be initiated in order to try and locate other possibly infected plants.

Late blight can sometimes be found on other crops, weeds and ornamentals, such as petunias, nightshades, and tomatillos. Spores travel through the air, land on plants, and if the weather is sufficiently wet, cause new infections. Once infected, plants may wilt and die within three days.

Late blight was a factor in the Irish potato famine in the 1840’s, during which millions of people in Ireland starved or were forced to emigrate.

For more information about identifying late blight and how to control it, visit http://vegetablemdonline.ppath.cornell.edu/.

If you suspect that the blight has infected your plants, you can call Cornell Cooperative Extension of St. Lawrence County at 379-9192.