The devastating fungus responsible for the Irish potato famine of the 1840s has returned with an attitude, scientists are warning.
A modern, meaner version of the fungus, which causes the disease known as late blight, infiltrated potato and tomato crops in New York and Maine in 1992. By 1995, it had worked its way into almost all Eastern states, and by last year was plaguing Texas, Idaho, Colorado and South Dakota.
"The re-emergence of late blight in the United States and Canada, as well as throughout the world, illustrates that even old diseases can become serious again," researchers from Cornell University wrote in the journal Plant Disease.
The new strain, which has become the dominant form of late blight in the country, is a serious threat to the potato industry, the researchers report. The fungus is extremely aggressive, able to destroy healthy potato fields within days.
This epidemic may prove difficult to control. The strain is resistant to the most commonly used fungicides. Potatoes that are obviously diseased can be destroyed, but this does not guarantee that spores hiding on stored potatoes will not infect harvests, they say.
Scientists might develop blight-resistant potato plants, but that solution may take a decade or more.