It was estimated that Saskatchewan growers spent over $800 million on herbicides in 2018. Despite improvements in crop competitive ability and cultural weed management, herbicides are the still the most effective method of weed management utilized by growers in Saskatchewan. Herbicides represent a major expense to growers and now represent the second most expensive crop production input after fertilizers. At the same time, the number of herbicide resistant weeds continues to increase, with new cases, such as glyphosate resistant kochia, demonstrating the need for improved herbicide regimes, new herbicide options, and alternative methods of weed management.

The Weed Science program at the Department of Plant Sciences conducted 218 trials in over 15 different crop species from 2019-2023.

Highlights of the 5-year research support include:

• Four graduate students defended during the time period of this grant (2 MSc., 2 PhD)
• Publication of 14 scientific manuscripts during the tenure of this grant
• Multiple highlights from the SPG program including new herbicide data for minor use registration, improved weed management techniques, and research on biological control of weeds.
• Differences seem to exist between oat varieties with respect to competitive ability.
• Wild oat control in oat is enhanced by a combination of inter-row spraying and weed wicking
• Post-dispersal seed predation is driven by olfactory cues in carabid beetles. Carabid beetles are highly specific with regard to seed selection, so not all weed seeds are consumed equally. Previous crop shapes carabid communities in pulse fields, and crop choice will therefore impact seed selection.
• The contract program with chemical companies ran over 1000 treatments, which resulted in registration of new herbicide or adjuvant products for Saskatchewan growers.
• Nearly $1.2M dollars in external funding was secured by the Weed Research Program for a 5-year period (2018-2023)
• Conducted research for private companies that led to the registration of several herbicides and adjuvants.
• Weed management is critical to the agricultural industry and is becoming more challenging due to increased levels of herbicide resistance.
• Integrating herbicides with good agronomy can produce excellent crops and reduce herbicide selection pressure. We have found many intriguing ways forward in a multitude of crops.
• Data indicate that inter-row spraying may be viable as an IWM tool in managing herbicide resistant weeds in lentil. Likewise, inter-row spraying, in combination with weed wicking, can helps reduce wild oat in tame oat.
• Oat varieties differ in their ability to compete with and withstand weed competition – there may be enough variability to improve selection for increased competitive ability.
• Carabid beetles are important weed seed predators in pulse crops and have higher affinity for specific weed seeds in their diet. Previous crop selection has a major impact on carabid abundance the following year, which in turn impacts seed predation levels