[Video shows Dr. Robert C. Scott, Extension Weed Scientist standing in a soybean field with pigweeds.]

Today I’d like to discuss the control of glyphosate-resistant Palmer pigweed or Palmer amaranth in soybeans. Once palmer amaranth has reached this size and glyphosate and other control measures have failed, there are no chemical control options to control pigweed at this size.

The conventional herbicide, Flexstar, which contains the active ingredient fomesafen, is effective in controlling glyphosate resistant Palmer pigweed. However it’s only effective if sprayed when these pigweeds are two the three inches tall. [Dr. Scott standing in a soybean field with pigweeds. Flexstar (fomesafen) is effective at controlling glyphosate resistant Palmeri Pigweed but only at heights of less than 3 inches. ]

In a salvage situation which we have here, we end up killing some of the pigweed. Other pigweeds may have the top burned out with some pretty severe necrosis. However, most of these pigweed will continue to produce seed in this field.

So in those where we need to stay in soybeans following the occurrence of glyphosate-resistant pigweed, we can rotate to LibertyLink soybeans. LibertyLink soybeans will tolerate the herbicide Ignite. Ignite can provide an effective control option for glyphosate resistant pigweeds. [Dr. Scott standing in a soybean field with pigweeds. LibertyLink soybeans will tolerate the herbicide Ignite. Ignite can provide an effective control option for glyphosate resistant Palmeri Pigweed. ]

[Dr. Scott] See the MP 44 or contact your local county agent for the best recommendations for using Ignite in LibertyLink beans.