Alliums Insects Pest Management

Leek Moth Update – 12 June 2012

The leek moth, Acrolepiopsis assectella, is an invasive species of European origin that attacks Allium spp., including garlic, onions and leeks. Since its detection in 1993 in the Ottawa Region, the leek moth has been problem for commercial allium growers and particularly to organic market garden producers in the region. Research by Peter Mason’s group from Agriculture and Agri-Food Canada suggests that this pest will likely spread further south and west from regions where it is currently found. Since 2009, leek moth has been detected in a few counties of northern New York State and in Vermont.

Figure 1. Leek moth pheromone trap

In 2011 leek moth pheromone traps (Fig. 1) were installed in Allium growing areas across southwestern and central Ontario. This pest was found in York Region, Simcoe County and Waterloo Region. Traps were checked for moths every week from late spring to fall. These pheromone traps attract the adult male leek moths; however, it is the larval stages of this pest that causes the damage (Fig. 2).

This year a similar monitoring program has been set-up in garlic and leeks in Ontario. Traps have been installed in various counties/regions across southwestern and central Ontario. Traps were set-up in mid-April at the Waterloo Region site that had leek moth last year. This was probably too late considering the warm week we had in March, so we likely missed the beginning of the first flight this season. From mid-April to the beginning of May, a total of 4 leek moth from the first flight were caught in the traps in Waterloo Region. There are generally three flight periods of leek moth per season in Ontario. Timing of these flights depends on environmental conditions but typically the first flight occurs from late April to mid-May, second flight from mid-June to mid-July and third flight from late July to late August. We will see how this year goes.

Figure 2. Leek moth larva feeding on leek leaf (this was taken in 2011)

Refer to Ontario CropIPM online at and OMAFRA factsheet—Leek Moth—A Pest of Allium Crops for more information.

If you suspect leek moth, please call Marion at 519-826-4963.

Coming Soon… Tips for Managing Leek Moth


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