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National Agriculture Genotyping Center to Offer Pigweed Resistance Screening (05/12/22)


The National Agricultural Genotyping Center will have a commercial assay available this year to test for PPO-inhibitor (Group 14) resistance in waterhemp and Palmer amaranth. They test for the most common mechanism of PPO-inhibitor resistance, which is the test that was used to confirm resistance in 7 counties in ND this winter. The test will be available for $75 per sample to anyone who wishes to submit samples. It is important to note that other mechanisms of PPO-inhibitor resistance are known in waterhemp and Palmer amaranth, but will not be tested for due to increased costs associated with those tests. It is also important to point out that this assay will NOT detect PPO-inhibitor resistance in monoecious pigweeds (redroot pigweed, smooth pigweed, Powell amaranth). The test will come back as inconclusive if a monoecious pigweed is submitted.

Please follow these steps for sample collection and submission for testing:

1. Wear gloves or use paper towels when collecting plant material. This limits contamination issues
caused by direct contact of plant material with bare hands. When sampling from multiple plants, be
sure to change gloves or use fresh towels between collections to limit accidental contamination
between the independent samples.

2. Place 2 to 3 leaves from a single plant into an envelope or paper bag. If the leaf is wet, dry prior to
placement or wrap in a dry paper towel to wick up moisture.
          a. Make sure only leaves from the same plant are packaged together.
          b.  Small plants or seedlings (less than 3 inches) ideally should be sent as whole plants,
               removing as much soil and moisture as possible before placing inside the bag. If the
               plant/soil is very wet, place inside a plastic bag prior to packaging in paper bag or envelope.

3. Once plant materials are packaged, clearly label each individual envelope/bag with a permanent
marker for identification. The identification (ID) label on the sample bag needs to match the
Specimen ID # listed on the Submission Form.

4. Complete and print off the Submission Form found on the NAGC website.

5. All shipments must be accompanied by a Submission Form. Send samples and completed
Submission Form to the lab as soon as possible after collection. Testing of samples will not
begin without a completed Submission Form
. Please do not place the Submission Form inside a
container that contains the plant material, rather place the Submission Form inside the shipping
box/envelope, but outside of the sample container.

6. If the sample cannot be sent the same day, it should be kept at room temperature. Samples should
be stored for no more than 1 to 2 days and PREFERABLY SHIPPED OVERNIGHT to ensure
samples arrive in good condition. Degraded samples cannot be tested.

Questions regarding sampling and shipping procedures can be addressed by contacting the National
Agricultural Genotyping Center Laboratory at 701-239-1451.


Ship Samples To:
National Agricultural Genotyping Center
1616 Albrecht Blvd N
Fargo, ND 58102


Joe Ikley

Extension Weed Specialist