If you plan to apply one of the new dicamba herbicide products on dicamba-tolerant soybean varieties, ask yourself these key questions. What is the dicamba formulation being applied? What herbicide tank-mixes will be needed? What adjuvants are required to enhance herbicide activity? Can you meet label and EPA standards? Can you maintain excellent weed control?
“We need to think differently than we have in the past,” says Jerry Ries, research and product analyst with West Central Distribution. “Our current thinking focuses on what will be the best solution for the field where we are making the application. Going forward, we also have to think about how the application will potentially impact nearby fields and various crops within those fields.”
The new dicamba and 2,4-D-tolerant crops require several mandatory considerations on the label. And they must be followed to the letter to avoid making illegal applications. It doesn’t matter what the requirements are, but rather how you manage the requirements to ensure maximum performance. “Everyone is striving to have clean fields,” Ries says. “You want to erase resistant and tough-to-control weeds, maximize the benefits of using the new herbicide-tolerant crops, and maximize yield potential.”
What has changed?
Dicamba and 2,4-D-tolerant crops are commanding attention. Minimizing volatility is paramount with dicamba-based . What are these formulations and what are the differences? Ries gives the following explanation.
The three products are XtendiMax from Monsanto, FeXapan from Corteva Agriscience and Engenia from BASF. XtendiMax and FeXapan are both dicamba DGA formulations. The DGA formulation has a much lower volatility than older forms of dicamba such as the DMA-dicamba in Banvel. To further reduce volatility, VaporGrip Technology is added. VaporGrip Technology slows the reaction of the dicamba-DGA to its acid form, which is more volatile.
Engenia from BASF also minimizes the amount of volatility, but in a different way. Engenia’s active ingredient is the BAPMA salt of dicamba. BAPMA salt of dicamba is the least volatile of all dicamba salt formulations: DMA dicamba (Banvel) is more volatile than K-Dicamba (Marksman), which is more volatile than DGA dicamba, which is more volatile than BAPMA. The BAPMA salt of dicamba inherently has very low volatility, so no additional ingredients are added to the formulation.
What adjuvants can’t be added to dicamba?
There are a few key things that cannot be added to either of the dicamba-based products, Ries says:
• AMS- or nitrogen-containing adjuvants. AMS and nitrogen increase volatility that can lead to off-target movement.
• Low pH products, when the tankmix pH gets around 5.5 and lower, volatility potential increases, defeating the built-in technology of either of the formulations.
• You should start thinking about your weed control long before the applications need to be made, he says. What are the problem weeds, and how big are they? Smaller is better than larger weeds when applying. What is planted in the fields adjacent to your field where you will apply dicamba? Are there natural buffers to be considered or endangered species?
“Sketch out your field and surroundings to start to develop a plan of attack,” Ries says. “When it comes time to spray, you will have a very good understanding of your surroundings.”
Do your homework
Check each of the manufacturer websites to ensure the products and adjuvants you will put into the tank have been approved. If a product isn’t listed, it cannot be added to the tankmix. Each website also covers other information such as approved nozzles and application information.
For detailed application information refer to the federal label and your state department of agriculture. Several states have added more application information details above the federal label, so be sure to check. CDMS and Agrian supply approved federal labels.
This is where it can get challenging
Remember the days when you added three, four or even more products to the tank to get your desired weed control? When mixing orders were extremely important? “Those days are back,” Ries says. “Sprayer tanks these days are often full of several products: herbicides, adjuvants, insecticides, fungicides and nutritional products.”
Correct tank-mixing procedures are absolutely a must to ensure effective weed control and not create a tank-mix nightmare, he adds. Understanding the order of products to be added to the tank will ensure the products that are being applied remain in their most active or effective form. If tankmix partners are added in the incorrect order, the result could be mixing issues or antagonism. “Again, be sure you plan ahead,” he advises. “Take the time early on to think about and plan the proper mixing order.”
Use correct adjuvant
Adjuvants play a key role in the performance of active ingredients in the tank. The adjuvants used also need to be approved and are listed on the website. Adjuvants perform several tasks: Enhance the active ingredient, aid in coverage, and aid in droplet formation and canopy penetration. “A grower knows what herbicides they will need to control their weeds,” Ries says, “but adjuvant selection may not be as clear.”
To help with the adjuvant selection, Ries says to look for multifunctional adjuvants. Multifunctional adjuvants enhance several or all the adjuvant functions stated previously. Veracity Elite II from West Central Distribution is one of those multifunctional adjuvants.
“Veracity Elite II is specially developed to satisfy the needs of the herbicide resistant crop,” he notes. “It contains a non-ionic surfactant that aids in droplet coverage on the plant, a non-AMS based water conditioner, a DRA approved drift control component that creates droplets in the optimal size range to maintain superior canopy penetration [and] excellent weed control, and it meets EPA wind tunnel standards.”
Minimize off-target movement, volatility
Ries says Veracity Elite II also maintains the built-in nozzle technology to maintain excellent spray patterns. It also includes a defoamer. “As a single adjuvant with all the advantages listed above, Veracity Elite II simplifies your adjuvant selection,” he adds.
Dicamba-based herbicide products provide excellent weed control. “To minimize off-target movement and volatility, and to maximize weed control, several things need to be done correctly, just like with all applications, no matter the herbicide, the crop or the environmental conditions,” Ries says.
What’s new that you should watch for in the future? Several other herbicide-tolerant crops are in the pipeline, such as HPPD and PPO tolerance. “When these and other types of traited-crops make it into production, they will also have similar types of requirements and standards that we have today,” he notes. “Sometimes it can seem a bit overwhelming but to ensure that we control yield-robbing weeds for a long time to come, the extra effort in planning your selection and use of these crop varieties and herbicide products will be worth it.”
credit:wallacesfarmer.com