Rx for Resistance

By Dane Bowers posted 07-17-2017 09:18


Sponsored content provided by Syngenta.

Growers Need Multifaceted Approach to Prevent and Manage Costly Weed Challenges

Over the years, we’ve all watched herbicide resistance evolve, with the threat oftentimes being ignored. We seem to think it’s a problem that happens to someone else in another area. In reality, resistance is a biological process that doesn’t have geographic boundaries. We’ve often taken the approach that if it isn’t obviously broken, we don’t need to fix it. With herbicide resistance, taking action now is the right approach. If weed-management programs are not properly designed, herbicide resistance will soon become an issue.

The practice most responsible for resistance is repeated use of the same active ingredient or mode of action. This puts tremendous selection pressure in the field, selecting for plants that carry resistant genes. As resistant plants escape, fields will develop high populations of resistant biotypes in fairly short order—in a matter of two to three years.

Another practice contributing to the evolution of herbicide resistance is applying post-emergence herbicides to weeds that are too large. Because some of these large weeds may have low levels of resistance, application at an earlier growth stage would have killed them. But repeating the process of spraying large weeds will, over time, build higher levels of resistance in the weed population. When growers begin to see that the herbicide rate they’ve been using is less effective and they must increase the rate, it’s a pretty good sign they’re developing a problem.

To help preserve the technologies available to them, I recommend growers plant into clean fields by either using an effective burndown herbicide or tillage. Also, consider adding more diversity into weed-management programs to decrease dependency on herbicides by removing weeds mechanically, rotating crops and planting cover crops.  

7593676822_be1369913a_b.jpgFor driver weeds, like waterhemp and Palmer amaranth, growers should adopt a zero-tolerance policy and not allow these weeds to go to seed, which further builds weed populations. It’s important that weed-management programs include multiple effective modes of action on the target weed. Using mixtures has been shown to be the most effective resistance- management strategy. Know what modes of action are in the herbicides being used, and make sure the target weed is susceptible. Many premix herbicides do contain multiple modes of action; however, target weeds, like waterhemp or Palmer amaranth, may be resistant or not controlled by one or more of the ingredients. This isn’t effective resistance management.

Two-pass programs are also important. Select a pre-emergence herbicide with multiple effective modes of action. This will lessen selection pressure on the post-emergence herbicide and help keep it viable. Where possible, use multiple effective modes of action in the post-emergence trip. Always apply the labeled rate at the correct time. I also recommend overlapping residual herbicides. Apply the post-emergent herbicide early, before most weeds emerge, for additional residual control. Controlling weeds before they emerge will help reduce selection pressure on the post-emergence herbicide.

To keep today’s weed-control solutions viable, Syngenta has research efforts underway—both internally and in external collaborations—to understand mechanisms of resistance and to monitor the development of resistance across the U.S. Our team is focused on education as well as the delivery of sound recommendations and herbicide mixtures to help customers manage herbicide-resistant weeds. We design our herbicide premixes to include robust rates, multiple effective modes of action and strong residual activity. When applied in a two-pass program, these herbicides will provide overlapping residual activity to help protect today’s weed-management tools.

Through our Resistance Fighter® efforts, the Syngenta Agronomy Service Team has developed local recommendations to provide good resistance-management strategies to our customers. We also have an educational component as part of Resistance Fighter. It includes hosting local meetings throughout the year and sharing information through collateral to help growers and retailers understand how resistance develops and what practices can help manage or prevent resistance.

Always looking ahead to the next challenge, Syngenta invests more than $1.3 billion globally each year in an effort to bring new solutions to farmers’ unmet needs. As a result of this focus, our current pipeline of technologies is stronger than ever. In the U.S. pipeline alone, we have more than 50 innovations. Specific to herbicides, we have new chemistries, premixes and traits in development. One example is MGI soybeans, which will allow in-crop applications of HPPD-inhibitors—a class of herbicides that offer exceptional residual control of grass and broadleaf weeds.

Syngenta also recently announced the name of a new herbicide featuring the active ingredients of S-metolachlor and dicamba. Upon registration by the U.S. Environmental Protection Agency, the herbicide will be marketed as Tavium® plus VaporGrip® Technology. We’re seeking approval of the S-metolachlor/dicamba premix for preplant, at-planting and post-emergence use on Roundup Ready 2 Xtend® Soybeans and Bollgard II® XtendFlex® Cotton, and preplant application on non-dicamba-tolerant soybeans. This premix will offer growers another tool to manage key ALS-, PPO- and glyphosate-resistant broadleaf and grass weeds with its built-in resistance management.

Our search for new solutions that can help growers manage resistance is never-ending. We look forward to continuing our partnership with retailers to bring these much-needed tools to farms. 

For more news and information on weed resistance and other topics impacting you and your customers, go to www.syngentathrive.com.

Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties. Please check with your local extension service to ensure registration status. Tavium plus VaporGrip Technology is not currently registered for sale or use in the United States and is not being offered for sale. Tavium® and the Syngenta logo are trademarks of a Syngenta Group Company. Bollgard II®, Roundup Ready 2 Xtend®, XtendFlex® and VaporGrip® are registered trademarks of Monsanto Technology LLC. All other trademarks are the property of their respective owners.