Proper sample collection for resistance testing is critical to ensure an accurate screening process can proceed. Multiple plants and adequate seed volume will ensure a good test.
Sample species that fit the criteria for resistance:
- Effective control on all but suspected species
- Effective control at other locations with this herbicide program
- Escaped weeds appear in rows (combine tracks) or near field entrance (contamination from other sources)
In addition, please print complete the form attached to this page and send it with the sample.
Are you planning a rescue treatment? If so, once suspected plants have been located, you may proceed immediately by carefully digging plants from the field and putting them into plastic or clay pots. Water the plants well before digging out of the ground. Do not allow soil to be removed from the root zone by working around the entire plant so that the soil/root mass roughly fits the container. Once transferred into the pot, water again and firm the soil lightly and place in a protected spot out of the sun until ready to transport. Plants must be healthy so they can be grown to maturity for harvestable seed.
Are the suspected plants mature? If so, collect mature seeds from 20-40 plants by clipping the seed heads from individual plants and placing in separate containers to air dry (paper bags or envelopes are sufficient). Generally, seeds are mature and viable if they have a hardened seed coat that is typically brown or black. Once dried, secure in individual containers with adequate labeling.
Forward sample(s) via courier, regular mail or personal transportation to:
Attn: Peter J. Smith
University of Guelph
Department of Plant Agriculture
Phone: 519-824-4120 x. 58372