The fungus p. infestans was first found in Europe causing the late blight rot of potatoes in the 1840s. In 1845/1846 the fungus destroyed all the potatoes in Ireland and 1.5 million people died. The fungus spread throughout Europe and caused potato crop failures until the late 1800s when the use of copper was found to be an effective fungicide for protecting potatoes from infection by p. infestans. The use of copper as a fungicide spray on potatoes became widespread throughout Europe in the early 1900s. However, in Germany during World War I, all the copper was requisitioned for making bullets. The German civilian population had become dependent on potatoes due to shortages of other foods. A late blight epidemic destroyed Germany’s potato crop in 1916 due to the lack of protection with a fungicide.
“…the last major famine caused by P. infestans occurred in 1916 during World War I. It resulted in the deaths of 700,000 German civilians, who were unable to protect their potato crop because copper was needed to produce bullets, rather than fungicides. Even today, more than 170 years after the Irish epidemic, frequent applications of fungicides are necessary to grow potatoes in moist climates, and losses occur even in dry areas, such as Israel and the western United States. Potatoes remain a fungicide-intensive crop, despite more than 150 years of study of P. infestans and the disease it causes.”
Authors: Schumann, G. L., and C. J. D’Arcy.
Affiliation: Marquette University, and University of Illinois.
Title: Hungry Planet: Stories of Plant Diseases.
Source: The American Phytopathological Society. 2012.
Over the past several decades, China has become self-sufficient in basic foods such as wheat, maize, and rice. In addition, Chinese production of many fruit and vegetable crops has soared. The widespread use of pesticides has had a key role in this vast expansion in food production and without their use…
“China would ‘undergo famine if pesticides were not used’. The warning has come in a recent Ministry of Agriculture document entitled ‘pesticide residues in agricultural products and related safety issues’, reports the national newspaper, the AgriGoods Herald.”
“China has more than 1,700 types of plant disease and insect pests, with major pest outbreaks occurring on over 400 million hectares annually. Laboratory findings released by Chinese agrochemical company Beijing Yoloo Pesticide showed that rice production would be reduced by more than two-thirds if pesticides were not used, and wheat production would be halved.”
Authors: Agrow staff writer
Headline: China warns of famine without pesticides.
Publication: Agrow. 2012. No. 642, June 20.
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.