NDSU Crop and Pest Report - May 23, 2013
Get Rid of those Large Weeds in Soybeans and Other Crops (6/7/12)
I have driven past many soybean fields that have large weeds, especially lambsquarters that survived tillage prior to planting. Weeds that survive tillage become very difficult to control with all herbicides, especially during dry conditions. The larger weeds become more difficult to control.
In Roundup Ready soybean fields with large weeds, apply glyphosate at 1.5 pounds acid equivalent/acre (Roundup PowerMAX at 44 fl oz/acre) as soon as possible. Add a non-ionic surfactant at 0.25 % v/v, unless the label prohibits the addition, plus AMS at 8.5 lb/100 gallon of spray. Tank-mixtures may be effective, but not likely with large weeds. Consult the North Dakota Weed Control Guide for additional information.
Do not allow any weeds to survive the herbicide application and be sure to wait 10 to 14 days before the second glyphosate application if weeds have survived the first application.
Jeff Stachler
NDSU and U of MN Extension Agronomist – Sugarbeet/Weed Science
