By Larry Steckel
The corn yields I have heard on dry land are ranging from 30 bushels per acre to a little over 100 bushels per acre. This stressed corn crop will obviously be very hard to harvest without a lot of small ears dropping through the snap rollers. With many folks intending to plant wheat behind corn, volunteer corn will likely be a big problem this fall. Volunteer corn germinating in August can be a big weedy problem in establishing wheat this fall. This happened quite often back in 2007. For the few fields planted to non-Roundup Ready corn hybrids, one can simply apply glyphosate to control the volunteer corn. That only entails a fraction of acres so what are some good options on volunteer Roundup Ready corn?
There are really two good options to control volunteer corn before wheat planting. Finesse at 0.5 ounces per acre tank mixed with 32 ounces per acre of glyphosate is a very good option. It will provide good knock down and residual control of volunteer corn as well as most winter annual broadleaf weeds and establishing annual ryegrass. This tankmix, on the other hand, will do nothing for Palmer amaranth control. The other option is Gramoxone at 40 to 48 ounces per acre. Go with the higher Gramoxone rate when volunteer corn is over 10 inches tall. A residual like Valor can be tankmixed with the Gramoxone up to 30 days before wheat planting. The Valor should provide residual control on pigweed and winter annual broadleaves but will likely let annual rye and Poa escape. Another residual option before wheat planting to add with Gramoxone is Sharpen. Sharpen at 1 to 2 ounces per acre may be applied right up to wheat planting. Like Valor, it will provide some residual control of Palmer and winter annual broadleaf weeds but will not help with annual ryegrass or Poa.
Steckel, University of Tennessee Extension Weed Specialist