Post Harvest Weed Control - September 2012
[University of Arkansas Division of Agriculture Research and Extension University of Arkansas System. Arkansas Soybean Promotion Board. Dr. Bob Scott, Extension Weed Specialist, Crop, Soil and Environmental Science, Lonoke Research and Extension Center, University of Arkansas Division of Agriculture, Lonoke Research and Extension Center]
I’m Bob Scott with the Cooperative Extension Service Division of Agriculture. [Bob Scott standing in a corn field.]
Corn is an excellent rotational crop with soybeans and cotton, especially if you’ve got Palmer pigweed. In corn, we can use products such as Atrazine, Halex™ GT, which contains several modes of action that aren't available in cotton and soybeans for the control of pigweed.
It’s important to remember in your rotational crops like corn to watch for late emerging weeds in the corn canopy. As corn begins to mature in the fall, the canopy opens up, the sun is allowed to hit the ground and we have a re-emergence of many troublesome weeds. Often these include Palmer pigweed, morning glories and grasses. [Video shows weeds between corn rows.]
Oftentimes in the fall, it’s very beneficial to follow corn harvest with a herbicide application to prevent these late germinating weeds from going to seed. There are a limited number of products available especially considering what you want to do with the field the following year. [Video shows a harvested corn field with weeds.]
Paraquat or Gramoxone® is a commonly used product following corn harvest to eliminate pigweed. [Picture of a bottle of Gramoxone® SL.] If you are planning on planting wheat, you may want to consider including a residual such as Valor Valor® can be applied 30 days prior to planting wheat.
In addition to Valor®, Dual® is an option if you’re not going to plant wheat. [Slide - Valor® Herbicide.] Dual® can be used in combination with Gramoxone® following corn harvest to prevent the germination of pigweed seed until we have a killing frost. [Video shows a harvested corn field with weeds. Slide - Dual®.]
[Bob Scott standing in a corn field.] For more information about pigweed control, consult the MP44 at www.uaex.edu.
[Find information in the MP 44 found at www.uaex.edu. University of Arkansas Division of Agriculture Research and Extension University of Arkansas System. Arkansas Soybean Promotion Board]