Resistance in Weeds and Microorganisms
Resistance evolves after a weed population has been subjected to intense selection pressure in the form of repeated use of a single herbicide. The first documented cases of weed resistance to glyphosate were found in Australia, involving rigid ryegrass (Lolium rigidum) near Orange, New South Wales.
Weeds resistant to the herbicide have been called "Superweeds". In the US 7 to 10 million acres (40,000 km2) of soil is afflicted by those superweeds. 13 states in the US have reporting resistance. Farmers associations are now reporting 103 biotypes of weeds within 63 weed species with herbicide resistance. Fifteen weed species have been confirmed as resistant to glyphosate.
In response, farmers are hand-weeding, using tractors to turn over soil between crops, and using other herbicides in addition to glyphosate. Agricultural biotech companies are also developing genetically engineered crops resistant to other herbicides. "Bayer is already selling cotton and soybeans resistant to glufosinate, another weedkiller. Monsanto’s newest corn is tolerant of both glyphosate and glufosinate, and the company is developing crops resistant to dicamba, an older pesticide. Syngenta is developing soybeans tolerant of its Callisto product. And Dow Chemical is developing corn and soybeans resistant to 2,4-D, a component of Agent Orange, the defoliant used in the Vietnam War."
Read more about this topic: Glyphosate
Famous quotes containing the words resistance and/or weeds:
“He made no resistance whatever, and was stabbed in the back.... I must not dwell upon the fearful repast.... Words have no power to impress the mind with the exquisite horror of their reality.”
—Edgar Allan Poe (1809–1849)
“What would the world be, once bereft
Of wet and of wildness? Let them be left,
O let them be left, wildness and wet;
Long live the weeds and the wilderness yet.”
—Gerard Manley Hopkins (1844–1889)