QUIZ – Fall weeds

Jay Whetter

kochia at harvest
Large kochia

Three questions on fall weed control – before and after harvest – including one on how to manage Christmas-tree-sized kochia.

1. By this time of year, kochia plants will have a lot of viable seed, even if most haven’t dropped or tumbled out or yet. That makes combine weed seed destroyers effective. As for pre-harvest herbicide, Charles Geddes, weed research scientist with Agriculture and Agri-Food Canada, cites a recent study, which found that a pre-harvest application of glyphosate plus saflufenacil decreased viable kochia seed production by ___ per cent, on average, when applied 10 days before harvest. (Fill in the blank.) 
2. Fall weed control can clean up fields for next year. Why type of weed is best sprayed in mid September to mid October, before a killing frost? 
3. Group-3 ethalfluralin (Edge) applied in the fall can help manage glyphosate-resistant kochia as well as many other tough weeds. Can you apply ethalfluralin this fall on fields planned for canola next year?