Potato Famine Fungus Is Back
Actually that’s a bit misleading — the fungus that caused the Irish potato famine in the 19th century never really left. Until recently it was controlled relatively well with pesticides, but that is beginning to change with the emergence of pesticide resistant strains of the fungus.
About 1 million people died in the Irish potato famine which, among other things, caused a huge migration of Irish nationals to the United States. The potato famine was the major cause of the failure of potato crops, but the cultural and economic institutions in Ireland and Great Britain contributed a great deal to the disaster as well. Exactly what share of the blame the fungus deserves and what share belongs to other causes remains hotly debated.
The disease is believed to have originated near Toluca, Mexico which lies just outside Mexico City. Although the area should be a prime area for growing potatoes, in fact it is all but impossible to grow the tuber in the area. The fungus attacks the leafy part of the plant, the tuber itself, and can also appear in potatoes in warehouses after harvest. Since potatoes are an extremely important crop around the world, fighting the fungus is extremely important.
U.S. researcher John Niederhauser has already made significant progress. He won the World Food Prize in 1990 for the work he had done creating blight-resistant potato varieties. From 1950 to 1980 Mexico’s potato production increased six fold and its consumption tripled thanks to Niederhauser’s fungus resistant varieties of potato.
Unfortunately the current resistant varieties still have some drawbacks. Some don’t make good french fries or take too much water or take too long to grow. Meanwhile the amount of pesticide that has to be sprayed on non-resistant varieties continues to increase. Where it might have taken one or two applications of the main fungicidal, metalaxyl, 20 years ago, today the fungicide has to be sprayed up to 12 times each season at a cost of about $200/acre. That price isn’t too much of an issue for farmers in the United States, especially large farms, but for farmers in Mexico and elsewhere in the developing world it is a lot of money.
Niederhauser and his colleagues believe it will be at least another decade before a blight resistant potato without the current drawbacks is widely adopted. Until then potato crops remain vulnerable to a fungal invader than can destroy a crop in just a few days.
Source:
Crop killing fungus spreads around the globe. The Associated Press, October 22, 2000.
The Potato Famine Fungus Is Back by Brian Carnell, unless otherwise expressly stated, is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.
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