Herbicide Resistance – A Plant Out of Place

Have genetically engineered herbicide-resistant crops increased or decreased herbicide use?

December 5, 2018 - by Andrew Kniss

It’s a simple question. And at first glance it seems like there should be a simple answer to this simple question. We have planted millions of acres of genetically-engineered (GE) crops, a vast majority of which are resistant to herbicides. In the U.S., we’ve collected lots of herbicide sales and usage data, spanning the entire time period when GE herbicide-resistant crops went from non-existent to dominating the landscape. So we should be able to simply look at the herbicide data before …

Herbicide resistance predates herbicides by over 80 years

July 27, 2016February 15, 2018 - by Andrew Kniss

The Weed Science Society of America (WSSA) recently posted a press release headlined “WSSA Scientists Say Herbicide Resistance Predates Genetically Engineered Crops by 40 Years.” From the WSSA release: You may think weeds resistant to herbicides are a new phenomenon linked to the overuse of glyphosate in genetically engineered crops, but according to the Weed Science Society of America (WSSA) nothing could be further from the truth. This year marks only the 20thanniversary of glyphosate-resistant crops, while next year will mark the 60th anniversary …

Agroecology / Crops / GMO / Herbicide Resistance / Herbicides / Imported from Control Freaks

Everything in Agriculture is a Trade-Off

March 14, 2016June 7, 2019 - by Andrew Kniss

The idea of trade-offs is familiar to everyone. None of us have unlimited money, time, or energy. We make decisions every single day about how to spend our money, our time, and our energy. Do I buy the red shirt or the blue shirt? Do I watch the football game or go to the concert? Should I ride my bike to work or hope I can find a good parking place? Do I call a plumber or try and fix the sink myself? Do …

The cost of preventing herbicide resistance

November 16, 2015February 15, 2018 - by Andrew Kniss

In my last post, I reviewed some recent research that suggests one of the best ways to delay the evolution of herbicide resistant weeds is to use mixtures of effective herbicides. Resistance is initially a very rare trait within a weed species, so the probability that any particular individual plant will be resistant to two herbicides is extremely low. The second herbicide is likely to kill any weeds that are resistant to the first herbicide, and vice versa. The theory behind this practice …

Want to reduce herbicide resistance? Spray more herbicides!

October 27, 2015February 15, 2018 - by Andrew Kniss

A while ago, I wrote a post summarizing the pros and cons of using a regulatory framework to slow the evolution of herbicide resistant weeds. As a part of that post, I suggested there exists a “resistance management paradox.” In a nutshell, to reduce the problem of herbicide resistant weeds, one important strategy may be to actually use more herbicide. From my previous post: “The only way to assuredly prevent herbicide resistance from evolving is never to apply the herbicide; but if we are going to …

GMOs, Herbicides, and the New England Journal of Medicine

August 20, 2015January 30, 2019 - by Andrew Kniss

An opinion piece was recently published in the New England Journal of Medicine, written by Dr. Philip Landrigan (an M.D.) and Dr. Charles Benbrook (PhD) titled “GMOs, Herbicides, and Public Health”. I was asked to review the piece this week, and I can only assume it will eventually make the rounds on social media. So I thought it was worth commenting here since it is related to herbicides and herbicide-resistant GMO crops. The “Perspective” piece is basically a plea from Dr. Landrigan and Dr. …

What does Chipotle’s switch to non-GMO ingredients mean for pesticide use?

May 18, 2015January 30, 2019 - by Andrew Kniss

A couple weeks ago, Chipotle announced they were removing genetically engineered crops (called GMOs) from their menu. Kind of. As you might expect, the announcement was covered widely in the media. Interestingly, though, most of the coverage wasn’t very positive. There’s a fairly long list of responses to the Chipotle decision if you’d like to read more about it. A variety of issues are covered in those responses, but I wanted to take a deeper look into the impact this switch might …

Superweeds: A Mutating Problem

October 8, 2014February 15, 2018 - by Andrew Kniss

Superweeds have been in been in the news a lot over the last few months. Most of the recent coverage has been related to new 2,4-D resistant crops that were recently approved by the USDA and the new herbicide formulation (2,4-D plus glyphosate) that the EPA is reviewing. Marc Brazeau recently wrote a compelling piece arguing that our focus on superweeds in GMO crops draws attention away from solutions that could really help make modern agriculture more sustainable. I’ve written about …

Regulating Herbicide Resistance

June 23, 2014February 15, 2018 - by Andrew Kniss

A few months ago, I wrote about 2,4-D resistant corn and soybean. At that time, the USDA had just completed it’s draft environmental impact statement for the two crops. While the USDA regulates crops developed through biotechnology, it is the EPA that regulates pesticide use. So before the new formulation of 2,4-D can be applied to the new corn and soybean varieties, it will need to be approved for use by the EPA. The comment period for the 2,4-D draft …

Fitness of herbicide resistance genes revisited

March 22, 2014February 15, 2018 - by Andrew Kniss

Last August, an article was published in New Phytologist that claimed a transgene added to rice could increase the fitness of a weedy relative. The paper was covered in the media pretty widely. When I read the paper, I didn’t think the authors presented nearly enough data to support their conclusions. You can find my criticisms in detail here. I think it is worth revisiting this paper now for a couple of reasons. The first is that two formal criticisms …