Reports by NC State extension plant pathologists indicate that since 1991, annual epidemics of late blight have affected tomato crops in the state's western counties. The state's potato-growing regions near the coast have a climate less favorable for disease development, but when conditions are favorable, an uncontrolled epidemic can result in 100 percent losses, as occurred in 1995. Late blight can destroy a crop in a matter of weeks. Within days of the first telltale brown specks on leaves and stems, an entire field can look as if it has been burned. Spores from infected plants can be carried hundreds of miles by the wind to land on healthy potato plants.
Potatoes are one of the world's four leading food crops, along with rice, wheat and maize.
Sexually reproduced fungicide-resistant strains of late blight pose an especially great threat in developing countries, where control measures may be nonexistent or too costly to use. Work to evaluate new fungicides is under way by NC State researchers and extension specialists. Here's a classic example of a disease most people think of only in a historical perspective. I'm not sure that future late-blight epidemics could cause famine on the scale you had 150 years ago in Ireland, but they could still ruin a crop and hurt farmers financially. As a historian, Peterson studies the impact the Irish potato famine had on the development of modern plant pathology.