Farmers continue to look for better ways to control broadleaf weeds. Herbicide-resistant species continue to spread and present challenges in a growing number of fields.

Farmers are using new trait technologies such as those in the Enlist™ weed control system and are planting more acres of herbicide-resistant crops to help limit the impact of these weeds. The Enlist weed control system works best when farmers understand the ins and outs of proper application.

“For effective weed control, the importance of using the right spray nozzle and the pattern it produces is something we cannot stress enough,” says Dave Hillger, Ph.D., Enlist field specialist. “Different spray nozzles and the way they’re used produce different patterns. The pattern impacts the effectiveness of weed control and the potential for physical herbicide drift.”

Droplet size matters

“The ideal spray pattern produces droplets that are large enough to stay where they are sprayed but small enough to provide effective weed control,” Hillger points out. “If droplets are too big and don’t cover enough of the plant with herbicide, you can get poor control and weed escapes. These escaping weeds can bear seeds, leading to future weed struggles.”

On the flip side, small droplets have greater potential to drift away from the target weeds or to evaporate quickly on hot, dry days. Both situations make the herbicide unavailable to control weeds. Fine particles, called driftable fines, that land on susceptible crops or plants nearby can cause injury.

“What is a driftable fine? The industry defines driftable fines as droplets of 150 microns or less. That’s slightly less than the thickness of a pin — slightly more than a human hair,” Hillger says. “Enlist Duo herbicide and Enlist One herbicide, both with Colex-D technology, are systemic herbicides that have been specifically formulated to reduce these tiny particles without increasing the relative droplet size. They provide excellent coverage with larger droplets that are less prone to drift.”

Technology plus correct nozzle reduces drift

This new approach to herbicide formulation and application was developed specifically to respond to grower and applicator needs and to address challenges with traditional 2,4-D products. Colex-D^® technology comprises three components: new 2,4-D choline, the latest formulation science and a proprietary manufacturing process.

During development of Enlist Duo^® herbicide, Dow AgroSciences research agronomists thoroughly tested numerous nozzles within manufacturer-recommended pressure ranges. They evaluated spray patterns to ensure plenty of nozzle choices were available to match today’s application technologies such as variable rate controllers that adjust operating pressure based on sprayer speed. The label for Enlist Duo includes 23 approved nozzles that are available for application. The label for Enlist One™ herbicide lists 47 nozzles available for application. The labels also detail the range of operating pressure (psi) for each nozzle. If a nozzle is not listed on the charts, don’t use it with Enlist herbicides.

Lab and field data show the formulation technology of Enlist Duo reduces driftable fines up to 45 percent as measured by downwind deposition. When Enlist Duo is applied using low-drift nozzles, driftable fines can be reduced up to 90 percent compared with applying a tank mix of glyphosate and traditional 2,4-D using an extended-range (XR) nozzle.

“Ninety percent is a significant reduction and should give growers peace of mind that they will have less risk of herbicide drift when applying Enlist Duo herbicide following label directions,” Hillger adds.

For more information about the Enlist system or product application, contact your local ag retailer, Dow AgroSciences sales representative or Enlist™ field specialist. Visit Enlist.com for valuable information, such as the product use guides and labels for Enlist Duo and Enlist One.

^®™Trademark of The Dow Chemical Company (“Dow”) or E. I. du Pont de Nemours and Company (“DuPont”) or affiliated companies of Dow or DuPont. Enlist Duo and Enlist One herbicides are not registered for sale or use in all states or counties. Contact your state pesticide regulatory agency to determine if a product is for sale or use in your area. Enlist Duo and Enlist One herbicides are the only 2,4-D products authorized for use in Enlist crops. Always read and follow label directions. ©2018 Dow AgroSciences LLC