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Dicamba: what you need to know for 2019

By Staff | Mar 1, 2019

Label changes have been made for the herbicide Dicamba to hopefully deter damage from the herbicide to non-dicamba soybeans and other crops.



There has been a lot of controversy surrounding the herbicide dicamba in recent years, but according to officials at BASF, if applied correctly it can be an effective weapon in a producer’s weed management arsenal.

Chad Asmus, BASF technical marketing manager, shared some dicamba-related updates during a recent media webinar, including what is new with the herbicide’s label.

What is dicamba?

Asmus said dicamba has been used for more than 50 years and, most recently, has been an effective tool for herbicide weed resistant management.

With the advent of the new dicamba tolerant crops, BASF developed Engenia herbicide, which, according to the company, represents up to a 90 percent reduction in volatility compared to older forms of dicamba.

Asmus said dicamba has the ability to control more than 200 of the most important broadleaf weeds, which is crucial with the resistance being shown to not only glyphosate herbicides but to atrazine, PPO, ALS and some HPPDs.

“What the advanced dicamba formulations like Engenia herbicide provides is a useful and effective tool to control those weeds,” he said. “And with the dicamba tolerant plant form that has been introduced into a lot of different soybean and cotton variety lines, a lot of growers are starting to utilize those genetics. With Engenia herbicide being a part of that overarching program, it will give growers the best ability to get those clean fields and high yields that they have planted that germplasm for.”

An effective weed management program

Asmus said an effective weed management program calls for using multiple and effective sites of action.

“Just don’t rely on one site of action,” he said. “If glyphosate has taught us anything, it’s that relying on one site of action for too long will cause it to break. Being able to use multiple sites of action is going to be the best way to steward the longevity of the dicamba tolerance system, as well as any herbicide type of action.”

He recommends including the use of pre-emergence residual herbicides.

“I like to say that the easiest time to control a weed is before it’s out of the ground, so if you can use a good residual herbicide program up front, that is a good way to mitigate weed resistance,” he said. “Reduce that weed pressure because that early weed pressure is what’s going to be detractive to yield potential.”

The use of a pre-emergent herbicide will also allow a producer to select more time for the proper post-emergent application window.

“We like to talk about having a plan in place and being proactive with the Engenia herbicide and the dicamba tolerance system,” he said. “If you have a good strong residual up front, you can look ahead. You know your application parameters and you can pick the day that you want to apply your Engenia herbicide post-emerge.”

“And, most importantly, it’s about preserving yield potential. You keep that weakened competition at bay, early on, to protect the yield potential.”

Asmus said it is important to plan for an early post treatment with a residual herbicide.

“Utilizing this technology, let’s try to target, let’s say three to five weeks after planting,” he said. “If that falls within the application window of your state, put that on your calendar and start looking ahead and look forward to the application windows that are best suited for that field. That will give you a reliable control for the small weeds, but also adding a residual herbicide at that time – like Outlook Residual herbicide, for example – will give you extended in season control to get you to canopy.”

Label updates for dicamba

There have been several label updates for 2019 for the Engenia herbicide.

  • Post-emerge application window

The new label says the herbicide can be applied from emergence to 45 days after planting, or up to the R1 stage, which is considered to be first bloom, or whichever comes first, Asmus explained.

  • Endangered species areas and corresponding buffer zones

Asmus said this is new for all of the advanced dicamba formulations.

“Fields that are in areas that have been identified as having an endangered species not only will require a 110-foot downwind buffer to the sensitive area, but an additional 57-foot buffer on the other sides of the fields,” he said.

Additionally, applicators can visit www.epa.gov/espp to see if your area has these additional use restrictions and a tutorial on Engenia stewardship resources page on the herbicide’s website is available as well.

  • Number of applications

Asmus said the total number of post-emerge application in dicamba tolerant soybeans of the herbicide is now at two.

  • Certified applicator requirements

The certified applicator requirement, as part of the restricted use pesticide, has been amended.

“Only certified applicators may purchase and use Engenia herbicide,” he said. “No longer can somebody who operates under the supervision of a certified applicator use or apply, but rather, only certified applicators may use and apply.”

  • Spray volume

Asmus said the minimum spray volume for Engenia herbicide is now 15 gallons per acre (gpa) versus the 10 gpa it was last year.

“This is going to enable a better coverage and better weed control for more consistent performance,” he said.

  • Sensitive crops

The label updates also include great definitions for sensitive areas, sensitive crops and residential areas.

“These areas are now clearly distinguished in the label and their corresponding downwind buffer requirements and wind conditions,” he said.

Asmus said sensitive areas are defined as bodies of water and nonresidential uncultivated areas that may harbor sensitive plant species.

Sensitive crops are defined as food, forage or other plants grown for sale, use or consumption.

“Residential areas are now also combined with sensitive crops,” he said. “Do not spray in situations when the wind is blowing in the direction of the neighboring downwind sensitive crop or residential area. We also added verbiage to call out that wind directions may shift during the application. You need to know, applicators need to know, what is around them and under what circumstances if the wind direction changes during that application. Do they need to cease that application?”

The definition of a non-sensitive area has also been expanded.

“This allows for greater flexibility for the applicator to understand what is included in a non-sensitive area,” he said. “Because now, motor managed areas adjacent to a field, like a roadside right of way, are considered to be non-sensitive areas.”

  • Application hours

Asmus said daytime application hours have been changed. Previously, application hours were set from sunrise to sunset, but now have been changed to one hour after sunrise until two hours before sunset.

“This has been consistent with our training and the importance of not applying during a temperature inversion,” he said. “It is still incumbent on the applicator to verify that there is no temperature inversion occurring even during these hours as well.”

  • Record keeping

Previously, Asmus said records needed to be generated within 14 days of application. Under the new label, they need to be generated within 72 hours and the planting date must also be reported. The buffer distance calculation must be included.

  • Rainfall

The 24-hour rainfall verbiage has been updated to now read that an application cannot be made if the expected rainfall amount may exceed the soil field capacity and result in runoff in the next 24 hours.

  • Training efforts

Training was required for dicamba last year, but with the new label, Asmus said it will be required annually.

“States will be determining how that annual training will be met,” he said.

Last year BASF trained 26,000 people.

“Our training efforts were well received,” he said. “The importance for applicators to understand not only the how, not only what the label says, but why the label says that has been an important aspect and continues to be of our training.”

What is being done for 2019 and how will the need be met for applicator training?

According to Asmus, universities in some states are providing dicamba applicator training. In others, the registrant is going to be providing the training. There are some circumstances where training is available from both, allowing the applicator to be trained by the university or a registrant’s source.

Last year, BASF introduced engeniastewardship.com, a “convenient one stop shop portal for all things Engenia stewardship and training,” Asmus said.

Some of the key aspects of the site include the dicamba training as well as links to state trainings and other registrant trainings.

“We want to make it as convenient and resourceful as possible for applicators to get what they need in the state where they reside to get the proper and required training,” he said.

New this year is an Engenia herbicide spray tool at engeniaspraytool.com.

“What this provides is a convenient and an easy to read forecast that is specific to the application requirements of Engenia herbicide,” he said. “We’ll have the allowable daytime application hours in there. We will also have an account for the 24-hour precipitation probability, the probability potential for inversion, wind speed and direction resulting in basically a stoplight recommendation – red, yellow and green.”

He added this tool can provide a 36-hour window into the future.

“An applicator can best pick what time is going to be suitable to apply that field based on the conditions and the wind speeds and the directions and what they need,” he said.

Additional resources available on the Engenia stewardship website include a checklist, educational videos and links to other websites.

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