Researchers test parasitic fly to combat invasive Japanese beetles in Canada

Researchers in Canada are testing the release of the parasitic winsome fly to suppress populations of the invasive Japanese beetle ^[1].

The initiative aims to provide a biological alternative to chemical pesticides for gardeners and farmers facing significant crop damage. Because the Japanese beetle is an invasive pest, its unchecked spread threatens local biodiversity and agricultural productivity across eastern Canada [1, 2].

Paul Abram, a research scientist in entomology and biological control at Agriculture and Agri‑Food Canada, is leading the effort alongside other entomologists on Prince Edward Island ^[1]. The strategy involves using the tiny winsome fly as a biological control agent [1, 3]. Unlike general insecticides, this parasitic fly specifically targets the beetle by parasitizing its eggs [1, 2].

While the primary testing is concentrated on Prince Edward Island, related observations of the fly have been noted in Nova Scotia and Newfoundland & Labrador [1, 3]. These sightings suggest the fly may already be establishing itself in various regions of eastern Canada ^[3].

The Japanese beetle has become a pervasive problem for homeowners and commercial growers. By reducing the number of beetles that reach adulthood, the winsome fly could potentially lower the overall population density of the pest [1, 2]. This natural predation cycle is a key component of integrated pest management, reducing the reliance on synthetic chemicals that can harm non-target insects ^[1].

Researchers began implementing these observations and releases in 2026 [1, 4]. The long-term success of the program depends on whether the winsome fly can maintain a stable population and effectively keep the beetle numbers below an economic threshold ^[1].