Cornell University says the plant disease known as "Late Blight" has been found on crops in Madison County.
The plant disease is known to damage tomato and potato crops.
"Late Blight" is caused by an organism known as "oomycete pathogen" which survives in potato tubers and can produce millions of spores, which could infect other nearby crops.
The University says the best way to spot "Late Blight" on potatoes and tomatoes is to look for black greasy lesions which usually shows up within 3 to 7 days after they are infected.
Late blight was a big factor in the Irish potato famine during the 1850's.