Early season weed control is important for preventing yield loss, as peas are poor competitors against weeds. A pre-seed or pre-emergent herbicide application is recommended, along with a timely in-crop application, applied when weeds are small and actively growing.
Pre-emergent herbicides can offer control of Group 2-resistant broadleaf weeds, which have limited in-crop control options. Pea yield can be reduced by up to 25% if weed control is delayed until four weeks after emergence.
Along with the Field Pea Growth Staging Guide, here are some tips to keep in mind when staging peas:
- Peas always have two scale leaf nodes at the base of the plant. These may be above or below ground or a combination of both. Scale leaves are smaller than true node leaves and branches may develop from these scale nodes.
- To properly determine field pea growth stage, dig up plants to identify scale nodes as they are not counted when staging.
- The first true node leaf is the first stipule (leaf) and tendril that unfurls. Only true nodes are counted when staging for herbicide timing. If unsure, err on the side of caution.
- Subsequent nodes are counted once the clam leaves have unfurled. Unopened clam leaves are not counted when staging.
- Base staging off of the majority of plants in the field.
Make herbicide applications early, when weeds are small and actively growing for best control. Avoid applying herbicides if the crop is under stress from recent frost, excessive heat or drought. Wait three days for the crop to recover.