Farmers are turning to an old technology this year to control weeds in their fields, dicamba. It has been around for about half-a-century. It is a corn herbicide, but soybeans have been modified to tolerate it since so many weeds have modified themselves to resist being killed by glyphosate, commonly known as Round-Up. The primary problem, says University of Illinois Extension Weed Scientist Aaron Hager, is waterhemp.
“Dicamba, in the 50 years that we’ve used it, has never been excellent on any of the pigweed species,” he explained. “It can be good, it can be very good, but it’s not excellent. It’s not as consistent.”
This inconsistency makes the timing of dicamba applications extremely important. Hager says most post applied herbicides are going to do a better job of controlling a full suite of weeds in a field when the weeds are less than three to four inches in size.
“Certainly with something like dicamba and waterhemp our recommendation of farmers is to treat very, very small weeds, but certainly go back in about 10-14 days and scout those treated fields. Look and see what the efficacy level has been because sometimes we can twist up some of these pigweed plants, but that doesn’t necessarily mean that they’re going to be completely controlled.”
It is possible for the weeds to recover, flower, and produce seed. And that, says Hager, is something to avoid.
Source: NAFB News Service