Notice: Using Internet Explorer may cause some issues with loading dynamic content such as Cash Bids. Please use a modern browser such as Edge, Firefox, or Chrome.

Dynamic Weather Icon for Today's Forecast
Weather N/A

MANAGE WEEDS WITH FALL-APPLIED HERBICIDES

10/10/2016

The increasing prevalence of fall herbicide applications for control of winter annual weeds may indicate that growers are becoming more aware of the benefits that these applications provide.  Fall-application of herbicides may be the most effective timing to control a number of annual and perennial weeds, including some of our hard-to-manage herbicide-resistant weeds. Fields where weeds are managed in the fall are often the most weed free in the spring.  Elimination of weed growth in the fall allows the soil to dry out and warm up more rapidly, and ultimately permits earlier spring operations and planting. 

Good winter annual weed control can also provide additional benefits as it relates to insect, disease, and rodent populations. Insects, such as black cutworms, are often less attracted to fields without vegetative growth. It is also known that at least six winter annual weeds, including purple deadnettle and henbit, are a host for soybean cyst nematode.  Furthermore, because of lack of vegetative cover, voles are less likely to invade weed-free fields.

When choosing a fall herbicide program, the weed spectrum must be considered.  For control of perennial weeds, such as dandelion, the best time for management is in the fall.  In this case, application of a combination of glyphosate + 2,4-D should suffice.  This combination will also provide adequate control of many winter annual weeds that are emerged.  The use of 2,4-D in combination with dicamba is also a good option for fields that contain only broadleaf species.  However, the lack of an adequate residual components with these programs will allow for additional weed emergence if the application is not made late in the season. 

For early fall applications, the use of a residual herbicide is necessary to manage additional weeds that germinate later in the season.  Also, the use of a residual herbicide when glyphosate-resistant marestail is present will help provide fall and early spring control.  Control of this weed species at germination or as a rosette in the fall is much more effective than spring burndown applications after the marestail bolts.  The potential downside of using a fall residual herbicide is reduced rotational flexibility.  Many herbicides are labeled for use in both corn and soybeans for the following season, while some are specific to a single crop.

Finally, it is important to remember that fall herbicide applications are not a substitute for spring residual herbicide applications.  Best management practices for controlling summer annual weeds, including glyphosate-resistant waterhemp, incorporate spring residual herbicide applications followed by in-crop applications. 

Contact your FS Crop Specialist for more information.

Fall-applied-herbicide.jpg

Related Articles

Sep 15, 2020

Find out how preharvest application may get weed escapes and excessive weed patches under control before the combine hits the field.

Sep 8, 2020

Fields where weeds are managed in the fall are often the most weed free in the spring.

Apr 21, 2020

Herbicide programs are most successful when you maximize their residual potential and when they include multiple effective sites of action on the targeted weed(s).

Related Videos

Feb 18, 2015

​Listen to Jeff Bunting, Crop Protection Division Manager, discuss crop protection strategies for your farm.

We have revised our Privacy Policy and Terms of Use.

Please read both of these documents as the changes affect your legal rights. By continuing you agree to these updates.

We have revised our Privacy Policy and Terms of Use.

Please read both of these documents as the changes affect your legal rights. By continuing you agree to these updates.