Ristaino said that on the East Coast, the disease typically begins each spring on tomatoes in Florida and then spreads to other areas by weather events. The spores that cause the disease can be carried on the wind, although Ristaino said that in 2009 most pathogen movement was the result of the shipment of infected plants from one part of the country to another.

The severity of the disease also depends to a large degree on the strain, or type, of late blight. Working with scientists at Cornell University in New York, Ristaino will determine the type of late blight found in farmer’s fields. Ristaino said 24 different late blight strains, or genotypes, have been found in the United States, and some of these strains tend to damage one crop, either tomatoes or potatoes, more than the other.

At the same time, different strains are more or less susceptible to different fungicides. In 2009, five different strains were found on tomatoes and potatoes, but one particular strain, US-22, did most of the damage, she added.

When reporting teams across the country find the disease, they will send samples to Cornell and North Carolina State and to Oregon State on the West Coast. At North Carolina State, Ristaino’s lab will determine the disease genotype. This information along with the location of the disease will be available through the online map.

The late blight website will also include information on how best to protect crops from the disease. Ristaino added that as she and other scientists identify late blight strains they should be able to track the development of strains that are resistant to various fungicides, information that should be extremely helpful in aiding farmers in managing the disease.

Ristaino said the project also includes an educational component. Summer internships will be available to undergraduate students who wish to work on the project.

The reporting and alert system is expected to be operational for the 2011 growing season, and Ristaino said she expects to begin receiving disease samples in early May.

She added that the disease typically moves up the East Coast as the growing season progresses. Late blight is usually found on North Carolina potatoes in June, while it’s usually found on tomatoes in western North Carolina in late July and August.    

This year, farmers should be better prepared than in the past when late blight makes its annual appearance.