In this episode of the Pests & Predators podcast, host Shaun Haney is joined by entomologist Carol Frost and PhD student Rachel Pizante of the University of Alberta to explore the surprising power of hoverflies in Prairie cropping systems. This conversation highlights recent research showing how treed field borders can dramatically increase the presence of beneficial insects—particularly hoverflies that not only act as pollinators but also predate on aphids.
Rachel Pizante explains the dual role of hoverflies, noting that the adults are efficient flower visitors, especially in canola, and the larvae feed on aphids, making them a valuable ally in pest control. One species in particular, Toxomerus marginatus, has been found to visit canola flowers at much higher rates than bees in certain trials in Alberta. Carol Frost adds that in Pizante’s study, treed borders supported more hoverflies per week—far more than grassy borders.
The discussion also touches on broader implications for farm management. The researchers emphasize that even basic treed field borders, regardless of species or density, provide measurable benefits by serving as nurseries and launchpads for beneficial insects. Beyond hoverflies, early data shows potential benefits for ground beetles, spiders, and wasps, with treed borders also supporting wasp movement into fields.
The episode also introduces a computer-based individual movement model that Pizante is working on, which simulates hoverfly behavior in and around canola fields to help quantify pollination impact based on border type.
For producers, the key takeaway is clear: maintaining or planting a variety of field borders—including treed —can enhance beneficial insect activity and provide ecosystem services such as pollination and pest control throughout the growing season.
The Pests & Predators Podcast is brought to you by Field Heroes, powered by the Western Grains Research Foundation. Learn more at fieldheroes.ca.
Subscribe: Apple Podcasts | Spotify | RSS | All Podcasts
