Palmer Amaranth

Photos of the Palmer amaranth and common waterhemp plants at cotyledon stage
(Left) Figure 1. Palmer amaranth cotyledons: long and narrow (Photos by Alfred Stark and Lowell Sandell) (Right) Figure 2. Common waterhemp cotyledons.

How to Differentiate Common Waterhemp and Palmer Amaranth Seedlings May 16, 2017

Growers should be on the lookout for common waterhemp and Palmer amaranth, which typically start emerging in the first or second week of May in Nebraska.

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Palmer amaranth
Figure 1. This female Palmer amaranth plant can produce up to 0.5 million seeds.

Watch for Palmer Amaranth in Conservation Reserve Program (CRP) Fields May 12, 2017

Palmer amaranth has not been confirmed in conservation plantings in Nebraska; however, the identification and occurrence of Palmer amaranth in CRP fields in Iowa has raised concerns among weed scientists and growers about its spread into conservation plantings in Nebraska and offer some suggestions for growers.

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glyphosate-resistant Palmer amaranth
Figure 1. A female glyphosate-resistant Palmer amaranth plant in a soybean field in south-central Nebraska. This plant has the capacity to produce up to half a million seeds. (All photos by Parminder Chahal)

Glyphosate-Resistant Palmer Amaranth Confirmed in South-Central Nebraska March 15, 2017

Palmer amaranth (Amaranthus palmeri S. Wats.) is a C4 dioecious species (separate male and female plants) native to the southwestern United States.

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Photos of pigweed species
Figure 1. Common pigweed species found in the Nebraska Panhandle. Palmer amaranth and waterhemp are ALS-resistant. Images, from top to bottom in each column, are of seed, seedlings, and plants in the vegetative growth stage. (Source Nebraska Extension EC94-138)

Management of ALS-Resistant Palmer Amaranth and Waterhemp in the Panhandle January 6, 2017

Palmer amaranth and waterhemp in the Panhandle are resistant to ALS-inhibiting herbicides. While control of these weeds in dry bean can be challenging, corn, irrigated small grains, and sugarbeet make good rotation options for control. A combined pre/post treatment strategy controls weeds in the early part of the season when crop yield is most impacted and weed species are most susceptible to control inputs.

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Depictions of Palmer amaranth in corn
Figure 1. (L) Palmer amaranth in corn and (R) a Palmer amaranth seedling. A member of the pigweed family, Palmer amaranth is a difficult to control broadleaf made even more difficult by its growing resistance to herbicides, including atrazine and HPPD inhibitors.

Managing Herbicide-Resistant Palmer Amaranth Field Day July 1, 2015

Learn how to get an edge on managing Palmer amaranth resistant to atrazine and HPPD-inhibitor herbicides Tuesday, Aug. 4 at a Nebraska Extension field day near Shickley.

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