Screening Waterhemp for Herbicide Resistance

We are pleased to announce that, with continued financial support from the Illinois Soybean Association, we are offering free screening for herbicide resistance in waterhemp during the 2013 growing season.  To date, over 1000 plant samples have been screened through this collaborative effort between the weed science program at the University of Illinois and the Illinois Soybean Association.  This valuable service helps farmers and researchers better track and understand the evolution of herbicide resistance in waterhemp across the state.

Details for collecting plant samples are as follows:

1) Following application of glyphosate, select five waterhemp survivors in the field.

2) Remove the top inch or two (containing young, newly emerged, healthy leaves) from each plant and seal inside in a sandwich-sized Ziploc bag. Use a separate bag for each plant.

3) Place the bags in an envelope and send by overnight delivery to Dr. Chance Riggins, 320 ERML, 1201 W. Gregory Dr., Urbana, IL 61801. Do NOT submit samples to the University of Illinois Plant Clinic.  Ideally, samples should be sent the same day they are collected. If necessary, however, they can be stored for a day or two in a refrigerator (but do not freeze) until shipped.  Do NOT mail samples on Friday or Saturday.

4) The sample submission form included with this article can be printed and should be completed for each field sampled.

There is no fee for this service, but please understand that we cannot guarantee when results will be available. Also, because of the way in which we conduct our resistance tests, a test result of “sensitive” to glyphosate does not rule out the possibility that the plant actually is resistant, but by a mechanism that is different than for what we are testing. Finally, we want to assure you that we will respect the privacy of those sending samples: we will not make the exact location of any samples, or names associated with samples, available to anyone without your permission. If you have any questions, feel free to contact Pat Tranel (217-333-1531;


Waterhemp Sample Submission Form 2013