Chemical Agriculture 204: Monoculture Failures

There are a number of examples of dismal failures of monoculture in agriculture.

Let's discuss three notable examples.

1. The Irish potato famine. Potatoes are a clone and most potatoes grown in Ireland in the 1830's had identical genetics. A potato extremely susceptible to "late blight" was widely grown. Poor folks ate potatoes, almost exclusively. When massive crop failures occured many people and a few immigrated to America. It was so bad the the population of Ireland literally crashed
2. Victoria Oat Blight.  The variety "Victoria" was resistant to crown rust but that same genetics made it susceptible to a blight that. Over 50% or US oat production was affected and losses were wide spread. So what you say, other than Mr. Quaker Oats why would anyone care. Well in 1940's when this was going on,American agriculture was still highly depended on the horse for power. Oats are high energy horse food of the first degree. No doubt this hastened the conversion to tractor power.
3. Texas Male Sterility. In the 70's scientists discovered a gene called the cms-T. This stands for cytoplasmic male steril Texas. This gene pervents femal plants from fertilizing themselves and you don't have detassel these fields. Sounds like a great innovation, as do it was until was discovered that this gene made the crop extremely susceptible to Southern Corn Leaf Blight. 90% of the crop was damaged and corn yield declines were dramatic. Use of the cms-T gene was rapidly discontinued.

These examples illustrate what can happen when we rely on an extremly narrow gene pool in a crop that is grown on a large scale. In some cases millions of acres. Michael Pollan calls this "equisitely  vulnerable,..because monoculture is poorly fitted to the way nature seems to work."