There have been several more reports of glyphosate-resistant (GR) Palmer amaranth being found in East-Tennessee. 

In some cases it is being found for the first time in new areas of counties already known to have GR Palmer. In other case it is being found for the first time in a county (Coffee County). 

It truly is amazing how quickly Palmer is spreading in east Tennessee considering that just three years ago Palmer amaranth, let alone the GR version could not be found there. Exactly how it is spreading so rapidly is anybody’s guess, but farm equipment movement has to be a top shelf suspect.   

One thing that is different in the eastern part of the state is that a good number of the growers have been relying heavily on glyphosate for corn weed control.

In a number of cases atrazine may be used pre-emergence and only glyphosate is used post-emergence. It is in some of these corn fields that GR Palmer amaranth is first identified instead of cotton or soybean fields, which was typical in west Tennessee.

Unlike first finding GR Palmer amaranth in cotton or soybeans where the only answer in many cases is disk and replant, in corn there are many good post options to control escaped Palmer. Several of these options are outlined on a May 1 blog posting.     

Because east Tennessee is in the early stages of GR Palmer amaranth infestation, anything a producer can do to stomp out the ember before it turns into a pigweed fire on their farm is advisable. Therefore, pulling up a few escaped pigweeds now can greatly reduce your herbicide bill next year. 

Likewise in fields with a large dense patch or two of GR Palmer amaranth in a field, it is advisable to disk it down or otherwise destroy that area.

(For an earlier report on pigweed in east Tennessee, see East Tennessee now feeling crush of resistant pigweed).