Re-posted from IPM in the South
“Those who cannot remember the past are condemned to repeat it,” said George Santayana in The Life of Reason. That quote seems fitting to apply to weed scientist Eric Prostko’s warning to growers about overusing herbicide-resistant technology in the absence of other non-chemical weed management. He authored an article in Southeast Farm Press named “7 lessons learned from the ‘glyphosate era’ we must remember.”
Prostko recalls the development of glyphosate-resistant crops that exploded in the US, leading to some of the worst cases of glyphosate-resistant weeds developing because of resistance. Now, he says, growers face another possible era of herbicide resistance, due to auxin-resistant, or AR, crops.
He lists seven conclusions that can be gleaned from the “glyphosate era” that he hopes growers will concern as auxin-resistant technology begins to have more prevalence in the fields.
- Glyphosate helped growers control larger weeds. 2,4-D and dicamba have never been very effective on large weeds, so they cannot be considered a replacement for glyphosate.
- GR-weeds evolved alongside GR-crops, not because of gene transfer, but because the technology was overused. Now 36 weed species worldwide are resistant to glyphosate, and 16 of them are in the U.S.
- Auxin herbicides are not new, and 32 weed species have already developed resistance to them. Eight of those weeds are in the U.S., so farmers and industry should be thinking of ways to prevent more species from becoming resistant to auxin herbicides.
- The last new mode of action was discovered in 1986. There is nothing new in terms of mode of action in the pipeline.
- When Palmer amaranth developed resistance to glyphosate, weed specialists had to resort to weed science. Weed science involves the combination of many sciences including biology, botany, chemistry, ecology, engineering, environmental sciences and plant physiology. Effective, long-term weed control depends on a combination of cultural, mechanical and chemical options.
- Every grower is responsible for implementing a weed resistance management plan, not just your neighbors.
- The public doesn’t like GMO crops. Misusing GMO crops and making headlines about their failure doesn’t help agriculture’s cause.
“Fighting Mother Nature is like fighting Jose Cuervo,” Prostko says. “Sooner or later you lose.” In the end, growers must use all of the weed management tools they have, including tillage, cover crops, residual herbicides, narrow row spacing, hand-weeding, crop rotation, and timely herbicide applications.