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Western Hemlock Looper Moths return for a third feast of B.C. foliage

Outbreaks of the moths occur every 11 to 15 years in Coastal and Interior forests
This year’s Western hemlock "looper" moth outbreak has been seen in the Lower Mainland and the Interior, including communities throughout the Columbia Shuswap Regional District. (Lorraine Maclauchlan photo)

North Vancouver is in the throes of another Western Hemlock Looper Moth outbreak, but there’s no reason to panic — unless you’re a tree.

Over the next few weeks, swarms of the moths are expected to descend on North Vancouver forests. During their larva stage, Western Hemlock Looper Moths feed on the foliage of western hemlock, western red cedar, douglas-fir and cypress trees. As the moths devour the foliage, it could look like the trees are done like dinner, but many of the damaged trees will recover given the right conditions.

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In a news release, the City of North Vancouver noted that they are in year three of their moth outbreak, which typically lasts four years and happens every 11 to 15 years.

This year, trees will be under extra stress due to prolonged drought conditions and extreme heat in much of B.C. The best way to help distressed trees is by giving them lots of water, so if a tree is looking stressed, give the roots a good soaking.

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Forecasters are calling for a rainy fall season for B.C.’s West Coast, which could help stressed trees survive and limit the proliferation of looper moths if it rains heavily during their flight period.

The moths were also spotted in B.C.’s Interior in 2020. Communities in the Columbia Shuswap Regional District were heavily impacted by the outbreak.

RELATED: Moth outbreak prompts concerns for forest health

As September rolls around, expect to see trees covered in Western Hemlock Looper Moths. By October, expect to see the ground littered with the moth’s table scraps and thousands of dead moths.


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