They say history repeats itself, and weed resistance to glyphosate (in particular) is sending growers back to the "old" way of managing weeds with pre-emerge herbicides.

Two decades ago, well before Round-Up Ready® (RR) corn  or soybeans hit the  market, pre -emerge herbicides ruled the day. With RR seed, it became easy to kill the weeds with glyphosate post -emerge, and the trend moved away from soil-applied herbicides.

But today, with weed resistance issues, "there's a better chance of winning the battle," said Rod Gustafson, Federated agronomist at the Albertville location, "when we control the weeds before they even get up out of the ground."

In some cases -- as with water hemp -- pre-emerge control may be everything. "We need to keep [waterhemp] from getting out of the ground," said Gustafson, who recommended layering herbicides, starting with a control layer, a pre-emerge with residual. New weeds, such as Palmer amaranth, are moving into the area, and they also demand pre-emerge control.

In Federated's Albertville service area, according to Gustafson, many growers start weed control by impregnating dry fertilizer with a pre-emerge herbicide (such as Dual Magnum SI). "We can get a free ride on the fertilizer," said Gustafson, saving a pass through the fields and getting the ever-important multiple modes of action.

Farmers need to be proactive, not merely reactive, in the battle to control glyphosate resistant weeds. "It will become a bigger deal if farmers ignore it," said Gustafson. "It's not going away."

In the quest to beat the resistant weeds, new herbicide programs must be used with care. It is predicted that without proper management, weeds could develop resistance in as little as four years to dicamba and 2-4D (as with RR Xtend2® or Enlist E3™ soybeans, for example).

While there is resistance to post-emerge herbicides, "there is not a lot of resistance to pre-emerge chemistries, yet," said Gustafson, "so pre-emerge is a very good tool that farmers need to use."

"Be proactive, not reactive," said Gustafson. Talk to your Federated Agronomist to determine your best pre-emerge options for this coming spring.