Making Timely Herbicide Applications to RR Soybeans in Fields with Palmer Amaranth

Ben Beale, Extension Educator, St. Mary’s County

Palmer amaranth infested soybean field in Southern Maryland.

The recent rains and numerous days of continuous wind has made it difficult to get herbicide applications made when needed.  Ideally, we really like to wait until planting to spray, or have good confidence that the herbicide application will occur right after spraying. Sometimes it doesn’t work out, and what we like and what we get are two different things.  With most weeds you will be ok, but Palmer and other resistant weeds can be another story. In our trials, residuals from pre-emergent herbicides provided 2-5 weeks of control for Palmer. That allows you to get in with an early post emergence product such as Reflex plus Glyphosate or Flexstar around 21 days after planting. This will help to keep the field clean until the beans canopy. If you take away a couple of those weeks, you can be in real trouble with weeds coming in before canopy closure. Continue reading Making Timely Herbicide Applications to RR Soybeans in Fields with Palmer Amaranth