This week is a welcome break from the fall chill, and it is a great opportunity to finish up any final fall weed management in pastures and no-till crop fields. Ideally, herbicide applications should be made when the sun is shining and daytime temperatures are above 50-55 degrees Fahrenheit. With high temperatures this week in the upper 60s and low 70s across much of the state, it’s a great time to complete this work.
Earlier frosts have eliminated most annual weeds, but winter annual weeds and more troublesome biennials and perennials are preparing for winter by moving energy reserves belowground. Systemic herbicides will be more readily translocated to those belowground plant structures to provide more consistent control of these weeds than at other times of the year. Before spraying, closely examine fields to confirm the presence and health of target weeds. Check the resources below for more information on fall weed management in different scenarios.
- Fall Burndown Treatments for Winter Annual Weeds
- Fall Weed Control in Pastures
- Effect of Frost on Pasture Weed Control
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on November 4, 2020. The information contained within may not be the most current and accurate depending on when it is accessed.
- Field Agronomist in EC/SE Iowa
- Field Agronomist in Central Iowa
- Retired Weed Scientist and Professor of Agronomy