Annual bluegrass (Poa annua) is quickly becoming one of the toughest weeds for the Peace Region’s creeping red fescue seed producers. Globally, it’s considered one of the most problematic weeds in turfgrass seed crops and although populations in Western Canada remain relatively low, they are increasing in both turfgrass systems and annual crop rotations. Creeping red fescue seed production accounts for about 65% of turf and forage seed crops in the Peace Region and contributes millions of dollars annually to the local economy. The spread of annual bluegrass poses a severe threat to seed quality, marketability, and farm profitability.
Currently, no registered herbicides specifically target annual bluegrass in Canadian creeping red fescue production. Recognizing this critical gap, researchers from the SARDA Ag Research Association, led by Calvin Yoder and Vance Yaremko, conducted a multi-year RDAR-funded project to test herbicide options for controlling annual bluegrass and evaluating them for tolerance on established creeping red fescue.
From 2021 to 2024, the research team evaluated several residual herbicides, including Focus®, Fierce®, Edge®, Olympus®, and Avadex®, with both fall and spring applications. A separate trial assessed post-emergent grassy weed herbicides for annual bluegrass control. Their goal was to identify treatments that effectively managed annual bluegrass without causing severe harm to the creeping red fescue.
Results highlighted both opportunities and challenges. Focus® and Fierce® showed effective control of annual bluegrass at most locations, but spring applications caused visible crop injury and reduced seed yield. Fall applications, however, were better tolerated. Fescue plants showed the ability to recover over time, suggesting potential for use in targeted spot treatments or along field edges. Fall applications of Fierce® caused visual damage to creeping red fescue but seed yields the following year were not reduced. In contrast, Avadex® and Olympus® caused no crop damage but were ineffective against annual bluegrass, though they may still offer value for controlling other grassy weeds such as wild oats. Post-emergent applied Centurion® controlled annual bluegrass effectively but causes severe fescue injury, limiting its use.
Weed pressure varied widely between sites and years, especially under dry conditions. At the Hythe locations in 2022-2024, extreme drought prevented annual bluegrass emergence altogether, reinforcing the idea that herbicide application may not be necessary in dry springs. These findings underscore the need for site-specific, weather-informed management and continued research into herbicide options that balance efficacy with crop safety.
Annual bluegrass’s ability to produce seed quickly and develop herbicide resistance makes it particularly difficult to control, especially if the same active ingredient is used repeatedly. Its patchy distribution, preference for wetter areas, and increasing presence in other cropping systems heighten the need for vigilant monitoring and management.
This research highlights an important step forward for producers managing annual bluegrass contamination in creeping red fescue fields. While challenges remain, these trials have set the groundwork for informed decision-making, improved seed quality, and better market positioning.
Please note that none of the herbicides used in this study are currently registered for use on creeping red fescue seed crops. Always read and follow label directions when applying herbicides. Product performance may vary depending on environmental conditions, application timing, and crop stage.
Funded in part by the Government of Canada under the Canadian Agricultural Partnership, a federal-provincial-territorial initiative.