BASF Expert Jeff Mueller on Managing Marestail Resistance and the Future of Ag Retail Agronomy
As herbicide resistance continues to challenge soybean production across key growing regions, marestail remains one of the industry’s most persistent and economically significant weeds. Once controlled largely through simple post-emergence programs, resistant marestail populations are now forcing growers to adopt more proactive, layered approaches to weed management.
According to Jeff Mueller, Seeds Agronomist with BASF, today’s successful programs increasingly rely on early burndown applications, residual herbicide layering, and close collaboration between growers, ag retailers, and manufacturers.
During a recent conversation with CropLife, Mueller discussed how retailers are adapting to rising resistance pressure, why communication and stewardship matter more than ever, and how emerging precision technologies may continue reshaping weed management strategies in the years ahead.
CropLife: From an ag retailer’s perspective, how has marestail evolved from a manageable weed issue into a broader operational and profitability challenge for soybean growers?
Jeff Mueller: A lot of the challenge really started when glyphosate programs became so heavily relied upon. We used Roundup on everything, and over time we built resistance into those populations. Now we’re seeing widespread glyphosate resistance along with ALS-resistant pockets, which really limits post-emergence control options in soybeans.
The biggest issue with marestail is timing. Once it bolts, it becomes very difficult to control. If it reaches seed production, then you’ve got another major issue because a single marestail plant can produce up to 200,000 seeds that spread easily through the wind.
Jeff Mueller
That’s why growers are increasingly seeing this as not just a weed issue, but a profitability issue tied directly to yield protection and long-term field management.
CL: With resistance continuing to spread, how are retailers adapting their weed management recommendations and agronomic service strategies to help growers stay ahead of marestail pressure?
JM: Retailers have done a really good job encouraging growers to focus on early-season management and starting clean. If growers know they have fields with a history of marestail, many retailers are recommending fall burndown applications to eliminate those overwintering rosettes before they become a spring problem.
The biggest shift has been toward proactive programs instead of reactive rescue treatments. Retailers are emphasizing layered residuals, multiple modes of action, and season-long management strategies instead of relying on one post-emergence pass.
CL: This season, there’s been a strong emphasis on layered residual programs and early burndown applications. How are ag retailers helping communicate the importance of proactive management versus reactive rescue treatments?
JM: A lot of it comes from experience. Growers have seen what happens when residual programs are skipped and fields become a train wreck later in the season.
Retailers have really helped communicate that the easiest weed to kill is the one that never emerges. If you’re relying entirely on post-emergence applications after weeds are already established, especially resistant weeds, control becomes much more difficult and expensive.
So retailers are helping growers understand the value of early burndowns, residual layering, and timely follow-up applications before weeds become unmanageable.
CL: What role does retailer agronomic expertise play today in helping farmers navigate increasingly complex herbicide programs, resistance management, and application timing decisions?
JM: Retailers have become trusted advisors for growers. There’s a lot more communication happening now around herbicide timing, field scouting, seed decisions, and overall weed management planning.
The retailers who build strong relationships with growers understand their fields, know what challenges they’re dealing with, and can help put together a management plan early in the season. That communication throughout the year is critical because resistance management really requires being proactive, not reactive.
CL: As post-emergence control options become more limited, how important is collaboration between manufacturers like BASF and ag retailers in developing practical, field-level solutions for growers?
JM: It’s essential. Manufacturers rely heavily on retailers to understand what challenges are showing up in the field and what growers need most.
Right now, we don’t have a large number of entirely new herbicide modes of action ready to go, so we have to maximize the tools we currently have through stewardship, better combinations, and stronger residual programs. That constant communication between manufacturers and retailers helps us continue improving how products are positioned and used.
CL: Looking ahead, how do you see weed resistance reshaping the future role of ag retailers — particularly around precision agronomy, stewardship, and integrated crop management strategies?
JM: Technology is definitely going to continue changing the role of retailers. Ten years ago, most retailers weren’t operating drones or using spot-spray technologies, and now many are.
As precision technologies continue evolving — whether that’s drones, see-and-spray systems, or AI-driven tools — retailers are going to play an even bigger role in helping growers manage weed pressure more efficiently and sustainably.
But stewardship will remain the foundation. Resistance management is always going to be part of the conversation because, as I like to say, “Mother Nature’s undefeated.” We always have to stay proactive and continue adapting our management strategies to stay ahead of these challenges.
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