by Ron Smith
Herbicide-resistant weeds are no longer a problem that could cause trouble for Texas farmers sometime in the future — rather, “Weed resistance is real and a problem across Texas, the country, and the world,” says Pete Dotray, professor of weed science at Texas Tech University and a Texas AgriLife Extension specialist.
Pest resistance, including resistant weeds, isn’t new Dotray said at a recent Ag Technology Conference on the Texas A&M-Commerce campus. More than a hundred years ago — in 1908 –resistance to an insecticide was first noted; fungicide resistance was identified in 1940; and weed resistance to herbicides was confirmed in 1957, when spreading dayflower was identified as resistant to 2, 4-D.
And from there, things only got worse, he says. “Globally, we know of hundreds of specific cases of weeds that are resistant to herbicides, displaying “an inherited ability to survive a previously effective herbicide application through biological changes in the resistant plant.”
Those changes may include:
- An altered site of action
- Changes in metabolism
- Enhanced expression of site of action
- Reduced uptake of the herbicide
- Reduced translocation