Chickweed Control with Cereal Herbicides

Mike Cowbrough - Weed Management Field Crops Program Lead/OMAFRA, Guelph
Francois Tardif - Department of Plant Agriculture/University of Guelph
Peter Smith - Department of Plant Agriculture/University of Guelph
07 May 2008

Objective

To evaluate efficacy of large chickweed with Infinity (pyrasulfotole/bromoxynil) compared to standard winter wheat herbicides used in Ontario under growth room conditions. Although chickweed is listed on the Infinity label (up to the 6 leaf stage of growth) chickweed is typically quite large at the time when most herbicide applications are made.

Limitations/Benefits

Control of weeds is usually better under growth room conditions compared to field conditions. However, if a weed is not controlled by a herbicide under growth room conditions, it is unlikely to be controlled in the field.

Results

• Infinity and Refine SG (tribenuron/thifensulfuron) provided the best control of chickweed.
• Re-growth of new chickweed leaf tissue was observed with Infinity compared with Refine SG .
• Bromoxynil/MCPA and dichlorprop/2,4-D did not control chickweed.
• The addition of ammonium sulphate (AMS) to Infinity improved efficacy of chickweed.

Figure 1. Untreated Control	Figure. 2. Refine SG: 2 weeks after application	Figure 3. Infinity + AMS: 3 weeks after application

Figure 4. Infinity: 3 weeks after application	Figure 5. Bromoyxnil/MCPA: 3 weeks after application	Figure 6. Dichlorprop/2,4-D: 3 weeks after application