• Crop Protection
  • May 19, 2022

4 Adjuvant Classes Proven to Help Improve Weed Control

Herbicide applicator climbing onto a sprayer carrying an adjuvant jug.
Supply chain issues continue to disrupt the ag industry, making it imperative to use resources efficiently and effectively this season. In many cases, there may not be enough herbicide supply available to fix mistakes or problems that arise during spray applications. Adding adjuvants to your herbicide tank mix can be a cost-effective way to enhance the performance of your spray application, improve weed control and mitigate against external stresses that can negatively impact weed control. Here are four adjuvant classes to discuss with your agronomic advisor.

Surfactants

Surfactants are used in herbicide formulations to increase surface contact, reduce runoff and increase leaf penetration. Typical surfactants include spreaders, stickers, emulsifiers and spreading agents.
 
Nonionic surfactants are water-soluble chemical and lipid compounds that reduce the surface tension of water to improve spreading characteristics. Due to their neutral charge, they are compatible with most herbicide products.
 
Nonionic surfactants will be critical for achieving effective weed control this season, especially when glyphosate rates are cut. Under those circumstances, the surfactant loads in glyphosate products are reduced. In addition, as the concentration of glyphosate product increases, the surfactant load decreases. Therefore, using a six-pound per gallon glyphosate product at a 90% application rate reduces much of the surfactant on the acre. Adding a surfactant such as Preference® adjuvant to the tank mix can help improve the spreading characteristics of the spray solution. Preference adjuvant contains a nonionic surfactant plus an antifoaming agent to help reduce surface tension on the leaf and slow the evaporation rate to improve herbicide uptake.

Water Conditioners

Water conditioners tie up cations including calcium, potassium and magnesium in water so that negatively charged herbicide particles don’t bind to them and reduce herbicide effectiveness. Ammonium sulfate (AMS) water conditioners are commonly used with glyphosate and glufosinate applications to improve herbicide performance. 
 
You’ll want to ensure that water conditioner rates are high enough to condition the water adequately, so I recommend a high-quality AMS-based product for glyphosate and glufosinate applications. Class Act® NG® adjuvant combines AMS with a nonionic surfactant and antifoaming agent in a liquid premix. One benefit of Class Act NG is that the pre-dissolved liquid AMS alleviates sedimentation and nozzle plugging in the sprayer. Plus, it’s formulated with CornSorb® technology to help improve herbicide uptake into the plant.
 
If you plan to spray dicamba, you’ll need to explore non-AMS-based water conditioners. Due to an increased risk of volatility, AMS water conditioners are not labeled for use with in-season dicamba sprays. But you’ll still need to condition water to optimize glyphosate performance with dicamba applications.
 
Class Act® Ridion® adjuvant is specifically formulated for use with in-season dicamba and is designed to protect glyphosate and other herbicides antagonized by cations in hard water. Class Act Ridion is a dual-chelation chemistry that provides premium water conditioning and includes CornSorb technology, two features that help improve plant uptake and set it apart from other non-AMS water conditioners.

Drift Reduction and Deposition Aids

Drift and deposition aids (DRAs) are formulated to optimize spray droplet size to keep more active ingredient on the intended target. Increased spray coverage helps improve weed control and results in fewer weed escapes, which is a key factor in limiting the development of herbicide-resistant weeds.
 
InterLock® adjuvant is a proven product formulated to reduce fine particles in spray patterns, reducing drift and promoting canopy penetration to help spray reach its target. It can help improve droplet coverage to ensure the spray contacts troublesome weeds. WinField® United research shows that including InterLock adjuvant and a DRA in the tank – along with a water conditioner – reduced driftable fines by 60%.1
 
UltraLock® adjuvant combines the chemistry behind InterLock with a proprietary polymer to improve canopy penetration, reduce drift and improve handling characteristics. UltraLock is compatible with a variety of tank-mix partners and is approved for use with in-season dicamba and 2,4-D applications.

Crop Oils

Crop oils could play a critical role in weed control this season as supply chain issues require farmers to rely on more oil-loving herbicides in their tank mixes. High surfactant oil concentrates and high surfactant methylated seed oils help emulsify the oil and lower the surface tension of the spray solution. These products can also make oil-loving herbicides more soluble in the spray solution and improve leaf penetration to increase herbicide uptake.
 
Destiny® HC adjuvant is a liquid high surfactant oil concentrate methylated soybean oil formulated to optimize the performance of most post-emergent herbicides. It also helps increase droplet drying time to protect herbicides against environmental factors like evaporation. Recent WinField United data shows that adding Destiny HC with a clethodim and glyphosate application on soybeans resulted in a 9.7 bushel per acre increase in yield compared to an application of clethodim and glyphosate without the adjuvant. That could mean a 23% increase in revenue – more than $125 per acre – for farmers based on a $12.90 soybean price.  
 
Superb® HC adjuvant is a high surfactant crop oil concentrate for use with glyphosate herbicides. This paraffinic petroleum oil is formulated especially for post-emergence herbicides that require a crop oil concentrate. Superb HC can typically be used at half the use rate of standard crop oil concentrates.  
 
This season, there may not be opportunities for do-overs on weed control. Improve your odds of success by adding an effective adjuvant to your herbicide tank mixes. Since each of these products delivers a slightly different benefit, work with your trusted advisor to select the best options for your situation and weed control needs.
  
12018 WinField United Innovation Center wind tunnel data.
 
All photos are either the property of WinField United or used with permission.

© 2022 WinField United. Important: Before use always read and follow label instructions. Crop performance is dependent on several factors many of which are beyond the control of WinField United, including without limitation, soil type, pest pressures, agronomic practices and weather conditions. Growers are encouraged to consider data from multiple locations, over multiple years and to be mindful of how such agronomic conditions could impact results. Class Act, CornSorb, Destiny, InterLock, Preference, Superb, UltraLock and WinField are trademarks of WinField United. All other trademarks are the property of their respective owners.



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