Signs of late blight appear suddenly but predictably in Ireland as soon as the summer weather turns humid, spores of the fungus-like plant pathogen wafting across the open green fields and landing on the wet leaves of the potato plants. This year it began to rain in early August. Within several weeks, late blight had attacked a small plot of potatoes in the corner of the neat grid of test plantings at the headquarters of Teagasc, Ireland’s agricultural agency, in Carlow.

It’s now more than a month after the potato plants were first struck and still a few weeks before the crop will be harvested. A large country house, housing the operations of Teagasc, overlooks the field trials, and well-dressed Irish and EU bureaucrats hustle in and out. Much of the sprawling building was constructed in the 1800s, during the worst of the famines that were triggered when blight devastated Ireland’s potato harvest. Such famines are far in the past, but the plant disease remains a costly torment to the country’s farmers, requiring them to douse their crops frequently with fungicides. As part of an EU-wide project called Amiga to study the impact of genetically modified (GM) plants, Teagasc researcher Ewen Mullins is testing potatoes that are engineered to resist blight. (Watch a video of Mullins and GM potatoes in Ireland at the bottom of this page or here.)

It’s breezy, and though the summer is over, it’s still warm and humid. “Perfect weather for blight,” says Mullins. Bending over the conventionally bred plants, he firmly pulls back the wilted stems and leaves to show that the tubers, half-exposed in the ground, are scarred with black blotches. Then he picks at a green leaf from one of the genetically engineered plants, which have been modified with a blight-resistant gene from a wild potato that grows in South America. The defenses of the potato plant have fought off the spores, rendering them harmless. The plant, says Mullins simply, “has performed well.”

To read full story from MIT Technology Review, click here.