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Scale-up and release of Diadromus pulchellus, a biological control agent of leek moth, and knowledge transfer of an Integrated Pest Management toolbox to growers

Project Code STB19-020

Project Lead

Kathryn Makela and Jacob Miall, Agriculture and Agri-Food Canada


To improve control of leek moth in Ontario and Quebec allium growing regions by increasing populations of the biological control agent Diadromus pulchellus and disseminating Integrated Pest Management (IPM) information to growers

The leek moth, Acrolepiopsis assectella, is an invasive alien species from Europe that causes damage to alliums crops, including onions, leeks and garlic. Allium production in Canada serves an important and growing market. For instance, the farm gate value of garlic increased from $1.67 million (M) to over $15M between 2003 and 2017 and dry onion farm gate value doubled from $45M to $91M over the same time period. Leek moth larva cause damage by burrowing into the leaf, weakening and withering the plant, while also providing the opportunity for secondary infections. Leek moth was first detected in Eastern Ontario in 1993 and has since rapidly expanded its range into some counties in southwestern Ontario, Quebec, on Prince Edward Island, in Nova Scotia and the US. CLIMEX models predict that eastern North America (where it is already present), as well as parts of Mexico, Oregon, Washington, British Columbia, and central Alberta are all suitable for leek moth survival. Furthermore, climate change is expected to intensify the problem, as it has been documented that more generations of the pest within a growing season results in greater damage to the crop, rendering later season crops unmarketable. Through previous work carried out by Agriculture and Agri-Food Canada researchers (PRR03-360 and MU03-ENT2), tools contributing to an IPM approach for leek moth were developed. These include the discovery, and initial release of the biological control agent Diadromus pulchellus, the development of a degree day model, knowledge about the use of row covers, identification and monitoring techniques, as well as testing of biopesticides.

This 2-year project will put into operation a multi-pronged, integrated approach to slowing the spread and reducing damage from leek moth in allium producing areas of Ontario and Quebec. Activities will include: scaled up production and releases of the biological control agent D. pulchellus in Ontario and Quebec; packaging of tools and knowledge about leek moth management into accessible formats; and knowledge transfer and dissemination activities such as presentations at grower meetings, articles in grower publications, online webinars and distribution of USB cards loaded with key elements of an IPM program for leek moth management, to increase awareness within the sector.

It is anticipated that implementation of an effective biological control agent in allium-producing regions before leek moth populations reach economically damaging levels could mitigate their capacity to harm the industry. The availability of a proven IPM program will also reduce risks to the environment, by providing an alternative to a chemical, calendar based spray program while protecting the biodiversity of native alliums.

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