Farmers and home gardeners are on the watch for a destructive disease that is hitting tomato and potato crops in New Jersey. 

The disease, called "late blight," has been found at five farms in New Jersey. Gardeners should keep a careful eye on the leaves of potato and tomato plants, advised Meredith Melendez, agriculture coordinator for Rutgers Cooperative Extension of Mercer County.

"The disease starts out as sort of greasy area on the surface of the leaf under the right conditions," she said. "If you were to flip over the leaf when we have those moist humid mornings, you would see spoilation occurring.  You will actually see it producing reproductive spores as an attempt to spread throughout the crop."

Melendez says now that there have been several confirmed cases of "late blight," commercial farmers and even home growers are watching reports of the disease as it travels.

"Once it gets close enough, they should start using preventive sprays," she said. "Organic growers will do the same thing -- they rely on copper sprays to ward off any of the spores that travel in the wind or even on people."

Experts say five or six days of hot, dry weather could shut down the blight.