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Palmer Amaranth ID of seed or plant tissue and Herbicide Resistance Testing at the University of Illinois Plant Clinic

Suzanne Bissonnette
June 12, 2017
Recommended citation format: Bissonnette, S.. "Palmer Amaranth ID of seed or plant tissue and Herbicide Resistance Testing at the University of Illinois Plant Clinic." Department of Crop Sciences, University of Illinois at Urbana-Champaign, June 12, 2017. Permalink

Are you having trouble with Palmer amaranth? We have something new for you.

NEW Palmer ID test available this year: We spent a long winter optimizing a new assay in collaboration with Dr. Pat Tranel’s lab to aide in Palmer amaranth ID. Contamination of seed mixes with Palmer amaranth became a wide-spread issue last year. Efforts to determine if a seed mixture is contaminated can be hampered by low germination rates and slow grow outs in greenhouse tests. A new molecular assay to confirm the presence or absence of Palmer amaranth in sample seed or leaf tissue is now being offered by the University of Illinois Plant Clinic. Up to 100 Amaranthus spp. seeds, or 5 plants, can be tested as a single mixed sample. To submit plant tissue, remove the top two inches of young, healthy, newly-emerged leaves from suspect Palmer amaranth plants. Only Amaranthus spp. seeds are accepted for testing; if you have a seed sample containing forbes, grasses, etc., please contact the Illinois Crop Improvement Association at (217) 356-4053 for assistance in separating the Amaranthus seed.

Figure 1:
Figure 1:  Waterhemp leaf extract prior to DNA extraction. University of Illinois Plant Clinic photo

Herbicide Resistance testing: The University of Illinois Plant Clinic also continues to offer herbicide resistance testing in waterhemp and Palmer amaranth in 2017, Figure 1. This is the third year the service has been offered at the Plant Clinic. Samples are tested using molecular assays for common modes of action for both glyphosate and PPO-inhibitor herbicide resistance. Currently, only waterhemp and Palmer amaranth are accepted for this type of testing. To sample, remove the top two inches of plants that have survived an application of glyphosate and/or PPO-inhibitor herbicides. Young, healthy, newly-emerged leaves are ideal for submissions. We recommend submitting five plants per field. Results are given on a per-field basis.

For results from last year’s tests, please see:

The fee for each service is $50 per sample. For additional information about how to sample, please see our flyer: and the molecular sample submission form:

Authors: Diane Plewa and Suzanne Bissonnette

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