East Tennessee now feeling crush of resistant pigweed

Well, it is official: We now have glyphosate-resistant (GR) Palmer amaranth coast-to-coast in the state of Tennessee.

I spent the last couple days of August in the east Tennessee counties of Franklin, McMinn and Bradley looking at soybean fields with GR Palmer amaranth. Franklin County has some soybean fields with GR Palmer amaranth at train wreck levels.

This is saying something as Palmer amaranth, let alone the GR version, could not be found there until two years ago. It is apparent now that the ability to tolerate glyphosate has helped Palmer become established into new areas.

That is not to say that east Tennessee soybean and cotton fields are as infested as the fields in west Tennessee. They are not. I am estimating the infestation level is below 20 percent. The folks in east Tennessee still have a chance to be proactive and at least delay the spread of this pest. But will they? If they do they will be among the few that are the exception to the rule!

There was a lot of debate in the academic ranks about eight years ago as to whether it would be more economical in the long-run for farmers to be proactive or reactive in glyphosate-resistant weeds.

There were actually several journal articles written on this subject. The general consensus was, as I remember, that it would be a little more economical in the long run to be proactive. However, I do not think anyone at the time was thinking about Palmer amaranth.

As we can easily see now with GR Palmer amaranth, “proactive” would have, hands down, been the way to go. It is not even close.

One can easily see now that using, for instance, a pre-applied herbicide in soybeans at $10 an acre that could have at least delayed resistance. That would be a heck of a lot cheaper than the $45 an acre worth of herbicides we throw at GR Palmer now — and, still, in some cases, we lose the field to Palmer.