Timely rains have improved attitudes for Oklahoma cotton farmers, but the ensuing weed explosion may be reining in some excitement.

While good soil moisture has made it easier to control some weeds like Russian thistle (tumbleweeds), difficulty controlling pigweeds this year is at an all-time high. Pigweeds can grow extremely fast when resources are available so thorough and timely scouting has been key in order to stay on top of the issue. Many producers that did not utilize early-season residual herbicides have been reminded that a rainfall event the day after their last glyphosate application can leave them with a brand new flush of pigweeds that grow three times as fast as their cotton. A few weeks later parts of the field can appear as though nothing was ever sprayed. In addition to this scenario, more producers are finding that even when they are timely and choose the correct rate and make their application in an appropriate manner, the glyphosate doesn’t work.

 Pigweed control issues in cotton have been experienced in Harmon, Tillman, Caddo and Custer counties for the past few years, and we recently confirmed glyphosate resistance in Jackson County as well.

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Glyphosate resistant pigweed (GRP) seems to be spreading at an alarming rate. Even producers who have utilized residual herbicides from the beginning are finding that in some situations perfection (100 percent control) is not realistic. Is 80 to 90 percent pigweed control acceptable? Where does that leave us? What can we do to survive the technology gap? Will we have technology next year that allows us to forget all of these problems and return to “easy-street” for the next 5 to 10 years? Unfortunately, we do not have many encouraging answers to these questions. For now let’s try to address our current problems.