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. (more…)