January 14, 2016
After significant drought across most of Oklahoma and Texas, growers didn’t want to complain about the overwhelming amounts of rain in early spring and the early 2015 growing season. The moisture was welcomed, but wet conditions moved the entire production season back about two weeks, delaying planting as well as herbicide application, both before and after planting.
Of course, plenty of moisture brought an increase in weeds. We also heard more reports of resistant weeds, especially where fields weren’t clean before planting and where residual weed control wasn’t in place.
“Up to this point, we’ve been fortunate that we’ve not had a lot of weed resistance,” says Jon Whatley, Odem, Texas. “We do a very good job in this area using different chemistries with our crop rotation, but resistance is coming. With the wet year, we’ve seen more of it. There were resistant weeds in fields that were not controlled, and I am going to have some acres with heavy weed pressure next year.”
Resistant waterhemp is an increasing problem in South Texas, and we have seen fields there overrun by glyphosate-resistant pigweed. In some areas of the High Plains, Palmer amaranth reached 5 feet in height. Growers who hadn’t seen herbicide-resistant Palmer amaranth in the past found they had difficulty controlling it with two applications of glyphosate.
We can’t control the weather, but the challenges it presented in 2015 offer important weed management reminders for growers as they begin planning for 2016.
Begin with scouting this fall
It’s important to scout fields and understand the weed spectrum in each field. If you have actively growing weeds this fall, consider fall tillage or a burndown herbicide application to clean up fields and prevent the buildup of the weed seedbank to help protect next year’s crop yield. Remember: Waterhemp generally produces about 250,000 seeds per plant. Palmer amaranth can produce around 500,000 seeds per plant and up to 1 million in ideal conditions. Like most weeds, the seeds remain viable in the soil for several years.
Program approach to start clean, stay clean
As you begin planning for 2016, use a program approach by selecting broad-spectrum soil residual herbicides with multiple modes of action. Preemergence herbicide applications — including a burndown — control early season weeds to create a clean field at planting, eliminating weed competition during the crop’s critical early growth. This window of early season control also provides time to get your entire crop planted and can help ensure timely application of postemergence weed control.
Apply on time, on label
The weed challenges of 2015 also underscore the importance of controlling weeds when they are small. Many postemergence herbicides must be applied when weeds are 4 to 6 inches or shorter. In ideal conditions, a weed such as Palmer amaranth can grow 2 inches per day, so that doesn’t leave much time for application. With new technology such as the Enlist™ Weed Control System, timely applications of Enlist Duo® herbicide at full labeled rates will help minimize weed escapes with a post application. Enlist Duo, a combination of new 2,4-D choline and glyphosate, also provides an additional mode of action to help control tough and resistant weeds when used with a program approach. Regulatory approvals are pending for the use of Enlist Duo on Enlist cotton.
By learning from the weed challenges of 2015, you can put together a weed control management strategy that will help you start with clean fields in 2016 and control weeds throughout the year.
For more information on developing a program approach to weed control for your farm and the latest herbicide-tolerant trait technology to help manage hard-to-control and resistant weeds in 2016, visit the Enlist YouTube channel, follow on Twitter at @EnlistOnline or visit Enlist.com.
™Enlist and Enlist Duo are trademarks of The Dow Chemical Company (“Dow”) or an affiliated company of Dow. Enlist Duo herbicide is not yet registered for use on Enlist cotton. Enlist Duo is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions. ©2015 Dow AgroSciences LLC
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