Tomato and potato growers beware.
A highly infectious fungal disease known as late blight has made its way from the Syracuse region to north of Plattsburgh, and it could make an appearance in the western part of north country any time.
Experts are urging growers to check their gardens for signs of the disease, which is marked by black or brown lesions on plants stems and leaves.
Spread by airborne spores easily dispersed by the wind, late blight was found recently in a garden in northern Clinton County. Experts say that finding suggests the disease traveled northeast across the north country from Onondaga County, where it was found last week.
As a result, late blight now is likely to be found in any vegetable garden in the north country, said Susan J. Gwise, horticulture educator for Cornell Cooperative Extension of Jefferson County.
Its probably here, but we just havent seen it yet, she said. Some gardens could be infected today.
Although theres not much gardeners can do once the disease strikes, Mrs. Gwise said, they can protect their plants now by spraying them regularly with fungicides until vegetables are ripe. The disease normally will destroy gardens in less than a week after its introduced, but its spread can be prevented if gardeners find it in its early stage. Infected plants should be uprooted from the ground and sealed in a plastic bag. The bag should be placed in the sunlight for several hours to kill pathogens before it is thrown away.
Ordinarily, late blight arrives in late August or September, when most gardeners already have picked their vegetables, Mrs. Gwise said. But unusually humid weather this summer has provoked its spread about a month earlier than usual. Rainy weather also can induce its spread.
Its usually not a problem, but most gardeners still havent picked their vegetables yet, she said. This will mostly affect small home growers because theyre not going to be aware of the signs of late blight until its too late.
Jefferson County is populated mostly with homeowners who grow small vegetable gardens, she said, but there are roughly 20 larger commercial growers who make their living selling vegetables here.
Mrs. Gwise said the last major spread of late blight in the north country occurred in June 2009, devouring gardens in Jefferson, Lewis and St. Lawrence counties in a matter of weeks.
It pretty much wiped out all of our potato and tomato crops, she said.
If the disease spreads here, the toll could be significantly lower this time around if growers take a proactive approach by spraying their gardens now with fungicides, which are effective only if used before the disease arrives.
To prevent infection, homeowners are recommended to use fungicides that contain chlorothalonil, spraying gardens every week. Options are more limited for organic growers, who may use only copper fungicides to treat gardens safely.
For more information, visit www.hort.cornell.edu/lateblight. Those who detect late blight in their gardens should call Mrs. Gwise at 778-8450.