The bogeyman of fungicidal resistance

Posted May 7, 2014 by Dale Wiehoff   

AgricultureFungicide ResistanceSustainable Agriculture

Fungus the Bogeyman (1977)

When my kids were young, one of our favorite nighttime books was Fungus the Bogeyman, a story about a subterranean bogeyman who spends his waking hours scaring humans. The kids and I loved all the disgusting bogeyman slang like pus and muck. As life would have it, the notion of fungus that frightens people has become only too real and instead if putting children to sleep, it has become the kind of story that really does keep us awake at night.

Recent news of the fungus wiping out shade-grown coffee in Central America was preceded earlier this month with reports of a wheat fungus in Africa that could wipe out this essential food crop. Major varieties of bananas in Asia and Africa are already being decimated by the deadly fungal Panama disease. Many important commodities are being plagued by fungal diseases and this increase in fungal diseases is not limited to plants. Just this week spores of a soil fungus that causes valley fever, or coccidioides, were discovered in Washington state. This fungus is normally found in regions with dry, arid climates.

Our defense against these dangerous fungal diseases has been fungicides. According to the pharmaceutical and chemical industry’s voluntary monitoring organization, Fungicide Resistance Action Committee (FRAC), there are currently about 150 fungicides in use, plus some other 50 compounds known as bio-fungicides. A few of these fungicides are broad spectrum and some are used to control diseases in plants and animals. Over time, fungi have developed resistance to many fungicides and it is this increased resistance that is contributing to the nightmare scenarios unfolding before us today.

Consider, for example, azoles, a group of broad spectrum fungicides and antifungals introduced in the 1970s; less than 30 years later, in 1999, fungal diseases were already showing resistance to them. Azoles are used to treat a range of fungal diseases in both plants and animals, including Aspergilla, which can cause life-threatening respiratory diseases; Aspergilla is now resistant to treatment.

As with resistance to antibiotics, overuse and improper use of fungicides in agriculture and clinical settings has contributed to fungicide resistance. During the 2010 to 2013 period of high commodity prices, farmers were urged to use fungicides to increase yields when no disease was present. Called “insurance fungicide,” this practice had been used earlier on wheat and was alleged to increase yields. Like nontherapeutic use of antibiotics in the livestock industry, insurance fungicide is another way to speed up fungal resistance to fungicides.

Fungicide resistance is a complex and hazardous problem that is likely to be worsened by climate change. Understanding how to prevent fungicide resistance by encouraging agroecological farming practices that don’t rely on fungicides, pesticides and antibiotics will help protect nature as well as public health. As we attempt to solve the problem of fungicide resistance we can’t ignore the economic drivers like trade policy and the concentration and industrialization of agriculture that have brought us to this sorry state. We are in a race for a sustainable and just future—at the moment, the bogeymen are winning.




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