Potato Late Blight
The Washington Post is not known for publishing articles describing the benefits of pesticide use. However, in a recent article about the development of a biotech potato in Ireland, a Post reporter described the current use of fungicides to control the late blight fungus. In the 1840s the Irish peasant population depended almost entirely on the potato for their diets. The late blight fungus destroyed the Irish potato crop in 1845 and 1846 and a million people died. Today, the fungus is well-controlled with regular fungicide spraying, a point made by the Post reporter…..
“The disease has become even more damaging in the past five years with the arrival of new, highly aggressive strains. Unchecked, blight can destroy entire crops in just days.
From the end of May until harvest, farmers spray fungicides every seven to 14 days, depending on the weather.
Without the sprays, the potato fields of Ireland would echo the destruction that began in 1845, when the blight took hold in Flanders and moved like wildfire to the British Isles.
More than a million died of starvation and disease, and as many as another 2 million fled to Britain, North America and other lands.”
Author: Adrian Higgins
Title: Modified tuber is no small potato in Ireland
Source: The Washington Post, March 17th 2013
The pathogen Phytophtera infestans causes a disease of potatoes called “late blight”. The pathogen grows in potato plants, breaking down cell walls so that it can use the nutrients found within them. Severely infected plants have an acrid odor which is the result of dying plant tissue. In the 1800s, Irish peasants subsisted almost entirely on potatoes. The late blight fungus arrived in 1845 and destroyed 40% of the Irish crop. In 1846, 100% of the crop was destroyed. Over 1.5 million Irish died of famine and a comparable number emigrated to America and other countries. Today, the fungus is still present in Ireland and would destroy the crop again if not for fungicides.
“Without the routine use of fungicides, large-scale commercial potato production in Ireland would be impossible. The cool, damp climate, which favours the cultivation of the potato and limits problems with virus diseases, is also ideal for the spread of blight. … In warm, wet weather when the humidity is high, P. infestans will lay waste an unprotected crop. … To prevent such devastating losses, the potato industry in Ireland has long been reliant on a substantial annual usage of fungicides.”
Author: L.R. Cooke
Affiliation: Plant Pathology Research Division, Department of Agriculture for Northern Ireland
Title: Potato blight control in Ireland: a challenging problem.
Publication: Pesticide Outlook. 1992. 13(4):28-31.