Late blight threatens LI tomatoes again

Late blight, the disease responsible for the great Irish Potato Famine in the 1840s, has resurfaced on Long Island for a third consecutive year.

It was detected Friday on tomato crops on two South Fork farms, according to Cornell University plant pathologist Meg McGrath. "I'm very concerned that late blight is going to continue to occur every year, especially if we don't all work together on managing it," she said.

Late blight is caused by a pathogen that can release millions of spores per plant per day, especially during wet weather. Those spores are carried by wind for potentially long distances until air currents or rain bring them back down, McGrath said. Theoretically, spores from one infected plant in Nassau County could destroy an entire crop on a farm in Riverhead.

The disease causes elongated brown lesions on stems and white-mold-encircled gray spots on leaves and stems that cause the plant to blacken, wilt and die. Home gardeners should inspect tomato and potato plants for symptoms. If late blight is detected, plants should immediately be bagged tightly in plastic and set in the sun for a few days until they die, then disposed of only in the trash.

Bring suspect plants to one of the two Suffolk CCE clinics -- 423 Griffing Ave., Riverhead, or the CCE office at Bayard Cutting Arboretum, 440 Montauk Hwy., Great River.