Special broom needed to clear looper poop 3 times a day: Cabin owner

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Joyce Zapotichny has never seen looper poop as bad as this summer.

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Zapotichny, who has a cabin in Johnson Bay in Indian Arm, about a half-hour by boat from Port Moody, says the voracious caterpillars have been feasting on hemlock needles this summer like never before. They’re messy eaters that take a few bites of hemlock needles before moving on to the next one.

As a result, Zapotichny says she’s had to use a special broom to clear the railings of her cabin three times a day of falling conifer needles — and the pests’ excrement, called frass.

“Probably the greatest nuisance with the inchworm is the poop,” she said. “It’s like dried grain but you know what it is so you don’t want it there.”

There was so much frass at the height of the caterpillar infestation that she and her husband had to put up a big canopy over their eating area.

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“They drop on your head from the trees above. They get into your clothing. You’ll look in your shirt and there’s one of them. I found one in my bra,” she said.

More than just a nuisance, Zapotichny worries the pests could also be worsening the threat of wildfires. Observers say they’re closely monitoring the situation.

Jesse Montgomery , head of environment management for  Metro Vancouver , said the Lower Mainland’s hemlock looper infestation is now in its third year and infestations typically last three or four years. For now, he says, there doesn’t appear to be the same kind of fire risk in coastal forests from looper moths as there has been in Interior forests because of the mountain pine beetle.

“With the experts we’ve talked to and the looks we’ve had at things, despite the tree mortality, we’re not anticipating a drastic change in fire-fuel loading in coastal forests,” he said.

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That said: “It’s something we’ll keep a super-close eye on.”

Montgomery said that within the watersheds of the Capilano, Seymour and Coquitlam watersheds, which supply drinking water to about 2.4 million people, the Capilano is so far the hardest hit area with what he described as a “pretty large level of tree mortality.” There may be even more tree deaths later this fall due to the additional stress caused by this summer’s extreme heat.

The looper infestation, he said, has spread throughout the Lower Mainland from isolated trees in residential areas to more forested areas. Loopers have also killed numerous trees in Stanley Park.

“In the watershed, we’re seeing it fairly contiguous cover hectares in size,” Montgomery said. “We’re seeing it most intensively on the west side of the Capilano watershed that’s quite evident from areas of North Vancouver and Grouse Mountain.”

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The western hemlock looper is known among foresters as a “destructive defoliator of its primary host, western hemlock, and associated conifers in northwestern North America,” according to a l eaflet published by the U.S. Department of Agriculture . Outbreaks tend to occur “during periods of above-average temperature and below-average precipitation, conditions which produce needles with more carbohydrates, which are a more nutritious food for larvae,” the leaflet said.

Southern B.C. has recorded at least 17 outbreaks since the first was reported from 1911 to 1914 in Stanley Park.

After feeding, the caterpillars transform into moths. This has already started to occur and will continue for several weeks throughout the region, Montgomery said.

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“From anecdotal reports, there was a high abundance of the larval form of moth this year — perhaps higher than last year,” he said.

Montgomery said looper infestations are a natural part of the coastal forest ecology. He predicted that the “forest will pop back in resilient matter with better biodiversity.”

Looking at the opposite side of Indian Arm, Zapotichny said she can see big swatches of dead trees that she attributes to the looper infestation. She’s worried about dead trees around her becoming fuel for fire in a few years when they’ve dried out.

“The longer they stand dead, the drier they get,” she said. “It’s not going to improve. It’s going to get worse.”

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