Adrian Percy
Getting Into the Weeds

Having sat through more meetings than I am able to recall, avoiding “the weeds” helps streamline the conversation by not getting bogged down in trivial details. However, there are times when simple generalizations aren’t enough and you have to dig a little deeper. Having recently returned from the 2nd Global Herbicide Resistance Challenge in Denver, Colorado, I think it’s fair to say that “getting into the weeds” is precisely what this conference was all about!


One of the biggest challenges farmers face today is weed resistance. Weeds are the most important factor affecting crop losses worldwide. Herbicides allow farmers to protect their crops from the threat posed by hundreds of millions of weed seeds that may lurk within each acre of soil. While chemical weed control remains the backbone of weed management, overreliance on simple herbicide solutions has led to the rapid spread of weed resistance. The International Survey of Herbicide Resistant Weeds currently lists 251 weed species that have evolved resistance to at least one herbicide, while noting that resistant weeds have been reported in 91 crops in 69 countries.


During the Denver conference, we heard from speakers in plant molecular genetics, non-chemical weed management, communications, socioeconomics, as well as from specialists working with insecticide, fungicide, and antibiotic resistance as part of an interdisciplinary program. I was honored to participate in a roundtable of experts from several different fields and to deliver a keynote regarding Bayer’s vision for the future of weed management solutions, but what really inspired me was seeing the dedication of so many talented people who will leave no stone unturned in their drive to solve the critical issues facing modern weed management.

Adrian Percy
That’s not to say this will be an easy task. Weed resistance is an existential threat and it’s not a question of where it will occur, but when and how severely it may strike. The challenge is to develop affordable resistance management strategies that make sense to support farming’s long-term economic and environmental sustainability.
Adrian Percy
Global Head of Research and Development for Crop Science

A key strategy of modern weed management involves the rotation of different herbicides which act in different ways (modes of action) at different sites (sites of action) to delay or minimize weed resistance evolution. Alternating or mixing control measures keep weed populations “off balance” and interfere with the natural selection pressure to develop resistance. While this can be quite effective, scientists have identified only about a dozen modes of action and about two dozen sites of action – a small number considering the thousands of weed species that are constantly evolving to out-compete the food we grow.


Relying on too few products to control too many weeds is a problem made worse by the fact that the discovery of new herbicides has declined dramatically. Incredibly, there have been no significant new mechanisms of action introduced over the past 30 years! While it is difficult to find new herbicides given weeds have evolved resistance to nearly all of the known sites of action, I’m proud to say that Bayer is “all in” in our commitment to herbicide research and our support of integrated weed management (IWM).


A fundamental pillar of our scientific approach to weed management is the Weed Resistance Competence Center (WRCC) in Frankfurt, Germany, where we test and develop new solutions to manage weed resistance, working in close cooperation with many external partners. By understanding the molecular and other mechanisms involved in weed resistance, we hope to develop new ways to detect and avoid the onset of herbicide resistance in major crops. No other company routinely runs as many samples to confirm resistance, including looking for target-site mutations and enhanced metabolism, which is where resistance begins in many weed species.


As we intensively work to discover novel herbicides, we can’t afford to forget about the here and now. We must make the most of the tools we have by using them in a sound IWM program. Today’s treatments have enabled growers to increase yields, minimize soil erosion and reduce water and energy consumption. Integrated programs help preserve these extraordinary benefits by using herbicides as part of a comprehensive approach, which includes the rotation of crops and traits and other non-chemical methods to make a weed’s easy path to resistance development much more difficult. Additionally, digital farming tools that help manage and outsmart weeds will increasingly play an important role in IWM.


That’s why I was so excited to be part of the Denver conference. We know there are no silver bullets, but innovative management practices are happening everywhere – often led by farmers who are at the forefront of this important battle. It was great to see farmers, universities and industry all working together to promote IWM and explore new approaches.

And best of all, nobody was complaining about getting into the weeds.