The Dicamba Factor to Weigh Heavily in 2018 Herbicide Decisions

The Dicamba Factor to Weigh Heavily in 2018 Herbicide Decisions

Sprayer Application

The strict guidelines for dicamba use means applicators will have an even tougher time in 2018, according to experts. Photo courtesy of FMC

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No surprises here: You won’t find any new blockbuster herbicides making a big splash in 2018. That fact, however, doesn’t mean that things will be quiet, especially with new dicamba technologies on the market.

Final numbers from Dr. Kevin Brad­ley, Professor in the Division of Plant Sciences at the University of Missouri, indicate that there are 2,708 dicamba-related injury cases currently under investigation by various state departments of agriculture around the U.S., and that there were approximately 3.6 million acres of soybeans that were injured by off-site movement of dicamba at some point during 2017.

“I told people last year I was cautiously optimistic we’d make it work; I was proven wrong. Yes, I am concerned (about 2018), because of the volatility,” says Bob Hartzler, Extension Weed Specialist and Professor of Agronomy, Iowa State University.

How things will ultimately shake out on the dicamba regulatory front is still a big question mark. Following EPA’s issuance of new labels for XtendiMax, Engenia, and FeXapan with tighter use restrictions, many state departments of agriculture are deciding whether or not they will impose any additional state requirements for the use of these products.

One point of contention: EPA has not yet specified whose responsibility it will be to take on both the duty and the cost of training applicators next year.

There are differences of opinion on the approach, with some states arguing that it’s a manufacturer’s problem. Most people we spoke with believe that public institutions will need to be involved in training at least in some way.

“I think it’s a manufacturer’s problem. It would require the total amount of funding for our people, but whether they are willing to pay (is another matter,),” Hartzler says.

Dwight Lingenfelter, Extension Associate, Weed Science with Penn State University Extension, remarks on the extent that the dicamba discussion has dominated his and many other ag academics’ and advisors’ professional lives over the past year, at the expense of sharing information on other effective products and weed management tactics.

“The impression we feel here, but also in talking to some of our colleagues in other states, is frustration that we can’t do the work we’d really like to with farmers. We feel in some cases we are the mouthpiece of the industry on dicamba, and that can be a challenging situation, especially with training — we’re not sure how that’s going to happen. All farmers are being mandated to do training now, and we’re not sure exactly what that means,” he tells CropLife®.

Regulatory and related fine details notwithstanding, Monsanto has, along with its licensees, set the stage to double acreage of Xtend crops to more than 40 million in 2018 and offer the trait in more than 300 varieties in its brands alone.

“The vast majority of growers had a positive experience with the system, and we are hearing from many who have a desire to significantly increase their on-farm use in the coming year,” Monsanto President and Chief Operating Officer Brett Begemann offered on the company’s fourth-quarter conference call. “For those who did not, we remain dedicated to improving their experience with the system, and we are actively developing plans to reinforce and expand our training and grower education efforts across the country. We’ll take full advantage of the months ahead to broaden and deepen the understanding of the technology’s application requirements so that more farmers can experience the benefits that this system can offer.”

EPA’s fine-tuning of label requirements for 2018, with which manufacturers have voluntarily agreed, are as follows:

  • Classifying products as “restricted use,” permitting only certified applicators with special training, and those under their supervision, to apply them; dicamba-specific training for all certified applicators to reinforce proper use;
  • Requiring farmers to maintain specific records regarding the use of these products to improve compliance with label restrictions;
  • Limiting applications to when maximum wind speeds are below 10 mph (from 15 mph) to reduce potential spray drift;
  • Reducing the times during the day when applications can occur;
  • Including tank clean-out language to prevent cross contamination; and
  • Enhancing susceptible crop language and record keeping with sensitive crop registries to increase awareness of risk to especially sensitive crops nearby.

EPA says manufacturers have agreed to a process to get the revised labels into the hands of farmers in time for the 2018 use season, and it will “monitor the success of these changes to help inform (its) decision whether to allow the continued over-the-top use of dicamba beyond the 2018 growing season.”

The strict guidelines for dicamba use means applicators will have an even tougher time in 2018, Hartzler says.

“They’re under pressure to get all these acres covered, and this is just a new twist,” he says.

Beyond dicamba, the other major theme in herbicides that emerged this year was the widespread group-14 resistance in waterhemp, according to Hartzler.

“Resistance is showing up in more fields in Iowa specificially, and that’s what is driving the interest in Enlist and Xtend soybeans,” he says. “Moving forward, we need to increase reliance on preemergent products and what we like to stress, but is never popular, is to look at how we can incorporate non-chemical tactics into the system.” He refers to 30-inch soybean rows dominating Iowa. “By going 15-inch, you develop that canopy so much earlier in the season. With an earlier canopy, late-emerging waterhemp is at a huge disadvantage.”

Liberty Expands

In October, BASF announced its $7-billion acquisition of Bayer’s non-selective glufosinate-ammonium business, sold under the trade name Liberty, and the LibertyLink trait portfolio, in addition to major portions of the Bayer seed business.

David Tanner, Liberty Product Manager with Bayer, sees sharp 25% to 50% sales growth of LibertyLink in 2018, as growers look to build their toolbox of reliable solutions to fight resistant weeds.

“For a long while, Liberty/Liberty­Link was a niche product for really tough acres; it wasn’t seen as something to go across the whole farm. I think growers are now starting to experience how well it performs from a yield perspective, and the overall convenience of the system — whether it be for buffers or tank mixability,” Tanner tells CropLife. “Liberty is going to be that dominant system in that other half of the market,” he says in response to Monsanto’s intention to capture half the market with dicamba.

Tanner adds: “There are no real new modes of action coming to market in next handful of years, so we need to do everything we can to steward Liberty properly … two-plus effective modes of action in the pre and two effective in the post (is needed) to really steward the chemistries we have. That’s one of the resistance management messages that we’re trying to drive, is to always mix multiple modes of action every time.”

Addressing the dynamic going forward between LibertyLink and Engenia — a huge portion of dicamba injury over the summer occurred on LibertyLink crops — Scott Kay, Vice President, BASF U.S. Crop, underscores the importance of expanding optionality for growers.

“I believe that having this new chemistry to add to our portfolio only helps to strengthen and broaden that approach, not just for today,” Kay says.

Along with the belief that grower choice should be maintained, Tanner reminds, “We need technologies to coexist, farmer to farmer, next to each other. They need to be able to coexist to allow multiple options to exist in the marketplace.”

Other Products to Watch

Aside from aforementioned herbicides in the spotlight, several new products are expected to make impact next year.

Dow’s Enlist corn, now with China’s long-awaited seal of approval, is one of them. This variety of corn is resistant to 2,4-D and works in concert with Dow’s Enlist Duo herbicide (glyphosate+2,4-D). John Chase, U.S. Commercial Leader, Enlist Weed Control System, discussed how the system will give growers another means to fight resistant weeds, which are now found on more than 100 million acres of U.S. farmland.

A key advantage of using Enlist Duo is that the required buffer zone needed for its application is only 30 feet (compared with 110 feet for dicamba-resistant crop spraying).

“Since most resistant weeds tend to be located along field borders and edges, this smaller buffer zone is an important way to make certain applicators are getting every weed with their application work,” Ryan Hoffman, Account Relations Manager for North-Central Co-op in Warren, IN, tells CropLife.

Chase adds that Dow is now raising Enlist soybeans in many test plots across the U.S. and that these too will be introduced to the greater agricultural marketplace once approvals from China are gained.

Elsewhere at Dow, the company is looking for a big market push for Resicore corn herbicide (acetochlor+mesotrione+clopyralid) in 2018 as well. According to Lyndsie Kaehler, U.S. Corn Herbicides Product Manager, Resicore can offer growers burndown and residual control of such tough-to-handle weeds as giant ragweed, waterhemp, and marestail.

With one successful season under its belt, Bayer CropScience is planning to expand the footprint next year of DiFlexx DUO, according to Frank Rittemann, Selective Corn Herbicide Product Manager.

Rittemann says the company is trying to convey that using a postemerge product like DiFlexx DUO offers control in-season but also helps reduce a grower’s weed seed bank for the following season. Scary stat: A single Palmer amaranth plant can produce from 100,000 to a half-million seeds, a Purdue University study found.

Another study, by the University of Illinois, found that by tankmixing 2.5 modes of action per application, growers are 83 times less likely to develop resistance compared to if only 1.5 modes of action per application were used.

Geared as the postemerge component of a two-pass system, DiFlexx DUO provides two sites of action that are active on both Palmer and waterhemp.

The one-two punch of a two-pass herbicide program is something Bayer stresses.

“I think we are starting to see better practices and weed control management,” says Mark Waddington, Product Development Manager for Selective Corn Herbicides. Although he sees the spread of glyphosate resistance continuing, he says, “I think growers are starting to realize the value of mixing herbicides, adding a residual component, and using a two-pass instead of one-pass.”

From FMC, Authority Supreme will be the newest addition to its Authority herbicide lineup in 2018. The product provides excellent control of waterhemp, Palmer, and pigweed in an easy-handling liquid formulation, says Flavio Centola, FMC Herbicide Portfolio Manager. EPA registration is expected in January.

Looking further down the road, the company has submitted a class-15, long-chain fatty acid inhibitor AI to EPA for registration.

“No resistance has been identified to this class, and we truly believe that class 15 will be a key part of growers’ weed management in the future. It will allow us to be more creative and enhance our formulations, which we’re excited about,” Centola says, adding, “That’s a class we’re investing in more and plan to introduce formulations and brands as we move forward.”

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