Waterhemp that has been found in Manitoba has been resistant to combinations of groups 2, 5, 9 (glyphosate) and 14. With soybeans and dry beans, it is easy to spot pigweeds poking up above the crop canopy at this time of year.
Check up on those pigweeds you’re seeing in the field. If their stems are rough and hairy, it’s likely red root pigweed. If stems are smooth, it’s time for more testing. You can collect plant samples and have them tested at the PSI lab in Winnipeg or contact Manitoba Agriculture for next steps.
Waterhemp:
- Emerges throughout the growing season, typically after most other summer annual weeds have been sprayed.
- Seeds may move with water, so scout along drains, creeks and in previously flooded areas.
- Flourishes in row crops due to more sunshine in the inter-row spaces.
- Produces 250,000 seeds per plant, and individual plants may produce more than one million seeds.
- Is a Tier 1 Noxious Weed, meaning all of the plants must be destroyed.