Cornell plant experts answer questions about tomato blight

Concerned gardeners, trying to learn more about late blight's appearance among local tomato crops, kept phone lines busy at Cornell University's Long Island Horticultural Research & Extension Center in Riverhead Friday.

The center received between 10 and 20 calls from people trying to find out more about the fungus-based pathogen, said Meg McGrath, associate professor and plant pathologist.

The second local case of late blight was confirmed in Bridgehampton earlier this week. In June, the first local case was confirmed at a community garden in Setauket, and affected plants were destroyed before the wind-borne pathogen could spread.

Signs of late blight include spotted leaves, dark lesions and rotted fruit.

McGrath said there was no indication yet of widespread blight. "I don't think it's too serious right now. We're kind of late in the tomato season," she said Friday. Cloudy, cool weather could spread the pathogen but even a moderately sunny day would allow the kind of UV radiation necessary to kill the spores, she said.

Still, anyone who spots the blight on their tomato leaves or fruit needs to take it seriously, she said. "It's such a devastating disease," McGrath said, and referred to the 1840s Irish potato famine caused by unchecked late blight on the country's crops. "The gardeners need to know."

Experts say infected plants should be sealed in garbage bags and left out in the sun for a few days to kill the pathogen. More information is available by calling the center at 631-727-7850 or visiting its website at http://www.longislandhort.cornell.edu/vegpath/photos/lateblight_tomato.htm

SEE PHOTOSThe 2010 Great Long Island Tomato Challenge