OSU weed scientists will again screen populations of any pigweed species this coming winter for their herbicide resistance characteristics, at no charge. This includes populations of redroot pigweed, waterhemp, and Palmer amaranth, among others. Samples should generally be collected from fields where resistance to one or more types of herbicide is suspected. The sample submission form with directions for collecting seed can be found at the “Herbicide resistance screening” link on the right side of our website, u.osu.edu/osuweeds/. Guidelines for collections are as follows:
1. Samples should be collected when seed is mature. Fully developed seed will be hard not soft.
2. Collect entire seedheads. Depending on species 10 to 30 seedheads are needed to have enough seed for a proper screening.
3. Sample should be fresh. Mail immediately or let air dry under cool dry conditions in an open PAPER bag for 2 to 4 weeks. Do NOT collect or store in PLASTIC
5. Samples should be carefully packaged and shipped early in the week to avoid weekend layovers during which the sample will deteriorate.
6. Be sure to include sample documentation and background information.