As a result of another wheat research effort, the EPA provided a Section 18 emergency exemption to the Oklahoma Department of Agriculture, enabling state wheat growers to use the herbicide Maverick on the fall, 1998 crop for the control of cheat. Wheat growers have never had a truly effective herbicide for cheat control. Cheat is a "first cousin" to wheat, and anything that controls it also damages wheat-until now.
OSU wheat scientists have been evaluating Maverick, which can
control cheat without damaging wheat. In tests from Haskell to
Goodwell, with several farmer-cooperators involved, researchers
from the Department of Plant and Soil Sciences are saying this
herbicide will control cheat in wheat.
The long-range implication is it means growers could consider
the use of no-till crop production, or minimum till at least.
In the past, low-till efforts meant cheat would eventually move
in and take over. Controlling cheat at all meant waiting for a
rain, waiting for the cheat to emerge, then harrowing it under
before planting wheat. This system made it hard to get early planting
in for a good wheat pasture situation.
OAES researchers tested Maverick on 33 wheat varieties. They
had to learn how much to apply under Oklahoma growing conditions
and when, and find out what its range of safety was. Are weather
factors critical to the success or failure of this herbicide?
Is it compatible with liquid fertilizers? They were pleased to
learn that answers to these questions were, "yes, and yes."
It is important to note that the Section 18 exemption label
restrictions do not allow planting a 1999 summer crop after wheat
is out, following a Maverick application in the fall of 1998.
More research is required to determine effects of Maverick soil
residues on rotational crops. The OSU researchers have already
looked at corn, millet, sorghum, cotton, soybeans, mungbeans,
and alfalfa to see if residues might affect crops that followed
wheat harvest.
Most were well within safe limits, but they did learn that sorghum will not be a good crop to follow wheat when Maverick has been applied. It "seems to think sorghum is cheat," the researchers said. They expect to have full EPA registration for this product by the end of 1999. Besides the OAES, this work was supported by the Oklahoma Wheat Commission, the Oklahoma Wheat Research Foundation, and the Monsanto Co.