Friday, May 7, 2010

Resistant Pests and Weeds

Agricultural weeds and honey bee pests regularly develop resistance to chemical treatments, especially when the chemicals are used repeatedly. Six authors present diverse views on the increasing problem facing American industrial agriculture as the list of weeds resistant to the most commonly used herbicide increases. Log onto today’s New York Times opinion piece at to read these authors’ thoughts on the causes of ten species of weeds evolving a resistance to Glyphosate. They also offer a range of possible solutions to correcting the problem by changing agricultural practices. Glyphosate, known by the name Roundup and other names, is used extensively with genetically modified crops that have been designed to be tolerant of the effect of the herbicide. While weeds evolve a resistance to Roundup in the fields, honey bee pests evolve a resistance to chemicals in the small environment of the bee hive. Beekeepers have seen American foulbrood, a bacterial disease, become resistant to antibiotics. Parasitic Varroa mites rapidly evolved to become resistant to each of the chemical miticides used in the bee hive. Corn, soybean, and cotton farmers are finding it necessary to use different herbicides and mechanical cultivation techniques to control Roundup-resistant weeds. Many beekeepers are moving away from the use of antibiotics and miticides in an effort to keep bees healthy without building strains of resistant pathogens and pests.

Today’s picture shows Palmer pigweed, one of the six species of Roundup-resistant weeds found in Arkansas. The plant, taller than a person’s head, stands outside a hundred-year-old barn at Peace Bee Farm. I regularly see Palmer pigweed standing above crops in nearby fields. Roundup is a most useful herbicide used by beekeepers to control foliage around bee hive stands. As a test, I sprayed the pigweed by the old barn with Roundup. The tall weed was easily killed by a single spraying at the labeled concentration; it was not resistant. Row-crop farmers and bee farmers should continuously evaluate their Integrated Pest Management approaches.

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