Field Day Focuses on Controlling Soybean Weeds
The University of Missouri Pest Management Field Day was held last week at the Bradford Farm east of Columbia. This meeting brings dealers and growers across the state to see the latest herbicide research. This is one of the most important meetings that I attend each year.
One of the important issues discussed was control of marestail and also tall waterhemp. The field day provided an opportunity to view herbicide research plots with different herbicides, rates and timings and the impact on control.
It is very apparent that we are waiting too late to control both of these weeds. Often we are trying to get as much value out of an herbicide application as we can by waiting late and trying to get as many weeds as possible. However, once you wait too late, then weeds become too tall for adequate control.
Often tall weeds are stunted from an herbicide application then soybeans canopy over top of the weeds and you do not see them in the field.
The use of glyphosate allowed us to control larger weeds. However, with glyphosate resistant water-hemp, when we discover escapes, the weeds are generally getting over labeled weed height of common post-emergence control product. Therefore, it is important to use
pre-emergence herbicide products for the control of this weed along with the glyphosate application.
For more information, contact Wayne Flanary at 660-446-3724, Heather Benedict at 660-425-6434 or Wyatt Miller at 816-776-6961, Regional Agronomists, University of Missouri Extension.