SCOTTS BLUFF COUNTY, Neb. – As the area prepares for the planting season, farmers must begin to think about weed control. One weed in particular is causing changes in the playing field.

This weed called Palmer Amaranth or Amaranthus palmeri is quickly becoming a challenging weed to manage. 

“Amaranth is the genus that Palmer is in and that’s the pigweed genus,” said Nevin Lawrence, Integrated Weed Management Specialist at the Panhandle Research and Extension Center. “We’ve got a lot of different species and many of them, farmers have been dealing with them for a long time here.”

Palmer amaranth is one of the newer species to the area but is presenting some problems.

Lawrence said, “It grows larger. It grows faster. It germinates over a longer period of time over the season. It’s more competitive and it produces more seeds. In every way, it’s just worse than the pigweeds we’ve dealt with in the past.”

Lawrence also stated that a major issue with Palmer amaranth is its resistance to herbicides.

“Certain populations of palmer amaranth can be resistant to up to 7 classes of herbicides,” said Lawrence. “In western Nebraska, where dry beans are produced, we don’t have all of those types of resistances in Palmer amaranth, but we have resistance to what’s called, one is glyphosate, that’s becoming more common, and we also have Palmer amaranth that is resistant to ALS-inhibiting herbicides.”

Dry edible beans are greatly affected by this. “The problem with that is the post-emergent options in dry beans are strongly reliant on the ALS-inhibiting herbicides,” said Lawrence.

Producers did have an effective option called Reflex until this year. Due to a number of factors including corn injury, Reflex is no longer available to our farmers.

“The company that manufactures and sells Reflex just had a lot of cases of corn injury apparently in our area and it wasn’t worth the risk of injuring the corn,” said Lawrence. “They decided not to renew the label when it expired.”

This leaves dry bean producers to wonder about other options.

“The one option that we sort of have left remaining in dry beans at the moment is a product called Outlook,” said Lawrence.

While classified as a pre-emergent herbicide, it is currently the only product that can be used after the beans emerge.

Lawrence said, “What you do with the Outlook is you would apply it to the dry beans after they emerge, but before your pre-emergent herbicide option has degraded in the soil.”

The timing for the application is still being researched as it is difficult is see herbicide degradation.

For more information, contact Nevin Lawrence at (308) 632-1230.