Dr. Bob Scott: Corn can be an effective crop for managing glyphosate-resistant Palmer pigweed. It can be a very good rotational crop with soybeans. Herbicides such as Dual and atrazine will provide very good early season control with Palmer pigweed and corn.
However, post harvest or at harvest growers may find that pigweed has reinfested many of these corn fields and action needs to be taken in order to prevent as much of this pigweed from going into the soil seed bank as possible. This can include tillage, mechanical push hogging or shredding, or chemical control means with a product such as gramoxone. We recommend at least 40 ounces of gramoxone, often times tank mixed with Dual herbicide to provide some residual control of pigweed. There is plenty of time in Arkansas between corn harvest and the first freeze to produce a second crop of pigweed, so care should be taken to prevent this from happening.
For more information on managing the soil seed bank for pigweed contact your county agent, check out the recommendations in the MP44, or go to www.uaex.edu for more information.
Your Arkansas soybean podcast is a production of the University of Arkansas, Division of Agriculture, and was funded in part by the Arkansas soybean promotion board. For more information on soybean farming in Arkansas contact your local county extension office.