We are having a Palmer pigweed heart attack
The current control measures in soybeans typically include using post-emerge PPO mode-of-action herbicides such as Flexstar, Cobra and Blazer, but these need to be applied when the weed is two inches tall. Control of two-inch resistant Palmer pigweed usually results in 95 percent control, but if the weed is allowed to reach four inches before the herbicide application then the result is only about 75 percent control. Naturally, control continues to decrease drastically every 24 hours that the pigweed is emerged.
“With only 75 percent control, you won’t combine that field of soybeans,” Steckel said.
He wasn’t extremely positive about relying on post-emergence herbicide applications for Palmer pigweed or other glyphosate-resistant weeds because timing is so critical and weather will interfere in application almost every year. He is highly doubtful that there is enough application equipment available to do the number of applications exactly when the applications need done.
A warning was to not try and spray more acres per day late into the evening or quite early in the morning, even though it is possible with today’s precision equipment allowing spraying in the dark. Temperature inversions commonly occur in the Midwest and South, which can cause major problems with off-target crop injury.
Steckel is telling farmers across the nation to learn from the Midsouth growers and do a better job in herbicide stewardship. “If you are filling out a scorecard, we are failing when it comes to trying to steward glyphosate.”
Steckel made at least two presentations during the Commodity Classic in Nashville as he was supportive of messages by Bayer CropScience and BASF concerning herbicide-resistant weed control.