Listen to this week’s agronomy Extension Corner on the benefits of fall spraying for winter annual weed control:
This is Aaron Nygren, your local agronomist with Nebraska Extension in Colfax, Cuming, and Stanton counties. If you struggled with control of marestail this growing season, spraying this fall is an excellent option to avoid problems next spring.
With harvest behind schedule, next years weed control doesn’t seem like a big priority. However, with the recent rains and cooler weather, winter annual weeds such as marestail and henbit have already started to emerge across the area. As you harvest, take time to scout for emerging plants, especially along field edges. Given the late harvest, scouting will help you prioritize which fields need spraying the most.
Even with the delayed harvest, we should still have plenty of time for herbicide applications, as good control is usually achieved as long as air temperatures remain above 50 degrees and weeds are actively growing. Some advantages of fall spraying are:
- Fall applications target the most vulnerable stage of growth for winter annuals
- Temperatures are typically warmer in the fall compared to the spring, leading to better herbicide activity.
- Even weeds not completely killed by herbicides are more likely to winter kill
There are numerous products labeled for fall application. Most commonly applications will contain 2,-4D ester and/or dicamba. Other products with longer residual control may give control into the spring, potentially reducing the need for spring burndown applications. If you have had issues with downy brome, you may consider including glyphosate for grass control. For a list of herbicide options and expected application costs, refer to EC130, Guide for Weed, Disease, and Insect Management in Nebraska, or figures 1 and 2 below.
Figure 1. Soybean Fall Burndown Herbicides
Figure 2. Corn Fall Burndown Herbicides
If you haven’t tried fall spraying and have struggled with winter annuals in the past, consider application on a field this fall, even if you have to have it custom applied. Given conversations with farmers across the area and my personal experience on our farm, you will be impressed by the level of control that can be achieved with fall spraying.
To listen to this radio message again or to get more information, visit our local website at croptechcafe.org or give me a call at 352-3821. This is Aaron Nygren, your local agronomist for Nebraska Extension on KTIC radio.
If you need some help identifying the winter annual weeds in your fields, check out the following resources:
2014 CropWatch Article – Identifying Fall-Emerging Weeds
North Central Regional Publication – Early Spring Weeds of No-Till Crop Production
