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No resistance to aerial gypsy moth spraying at Lake Cowichan

Spraying planned for this spring

Sharon Combs has concerns about the proliferation of the invasive species gypsy moth in the centre of Lake Cowichan.

But she said she is also concerned about plans by the Ministry of Forests, Lands, Natural Resource Operations and Rural Development to spray 231 hectares of the community this spring in an effort to stop the infestation in its tracks.

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Combs said that most of the information she received at an open house on Jan. 28 on the issue in Lake Cowichan that was hosted by the ministry suggested that the community has nothing to fear from the planned program.

“There are really high numbers of gypsy moths in the infestation in this area, so I came here to get more information on what is being planned,” she said at the open house.

“They say that the spraying will not be harmful to humans or animals, and that is one of my major concerns.”

The Lake Cowichan area is one of three chosen by the ministry to do aerial spray applications in the spring.

The others are 241 hectares of residential and municipal parkland in North Surrey, and 167 ha of semi-rural properties and wooded areas north of Castlegar.

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Tim Ebata, a forest health officer with the ministry, was surrounded by maps of the proposed spraying area and information about gypsy moths at the open house.

He, and a number of other experts in the field, spent the evening answering questions from the handful of Lake Cowichan residents who attended.

Ebata said 2019 was the second year that testing has indicated a growing population of gypsy moths in the Lake Cowichan area.

“The epicentre of the infestation is right in the middle of town,” he said.

“Urban forests with non-native species are a prime habitat for gypsy moths. They likely originated from somewhere between the Great Lakes and New Brunswick and were brought here by people on their vehicles. They are voracious eaters and once they take hold in an area, it’s hard to get the genie back in the bottle.”

Ebata said gypsy moths, which have been known to eat the leaves from up to 300 species, will defoliate entire trees, and repeated defoliation can kill the trees.

He said the ministry’s plan is to spray Bacillus thuringiensis var kurstaki (BTK) over the Lake Cowichan area three times, seven to 10 days apart, in May or June.

Ebata said BTK, which has proven to be effective in dealing with gypsy moth infestations, is a biological insecticide that occurs naturally in soil and is commonly used in organic agriculture.

“BTK is perfect for this purpose because it only affects caterpillars that eat sprayed leaves and has a proven safety record around humans,” he said.

“Livestock, pets, birds, fish, spiders, bees, ladybugs and amphibians are not impacted by BTK. Even the birds that feed on caterpillars are not impacted by BTK. BTK has been used successfully since 1961, and a large study that was recently completed shows that it has no ill effects on anything but caterpillars.”

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But Ebata said spraying BTK could be a concern for those who are sensitive to airborne particulates.

He said it’s recommended that those who are bothered by dust and pollen stay indoors up to an hour after the spraying is completed, and they should have their doors and windows closed during that time to avoid exposure.

Combs said one expert at the open house even suggested that all residents should remain indoors with their doors and windows closed until the spraying is completed as a general precaution.

“We’re hoping that the spraying will take care of the problem in Lake Cowichan, but we’ll be back next summer to test again for gypsy moths in the area,” Ebata said.

“The open house is part of our mandatory public consultations on our spraying program in order to receive a permit for the spraying.”

Lake Cowichan Mayor Rod Peters said he was satisfied with the explanations for the need for the spraying that were given at the open house, and that no adverse impacts on the population or the environment are anticipated.

“It should be a one-time deal, and what they intend to spray is not toxic to humans, pets or anything,” he said.

“I don’t see any real problems with this.”

Lake Cowichan resident Ginny Saboe said she came to the open house because she is interested in moths, especially the ones that seem to be proliferating in areas along Highway 18 in recent years.

“I found out at the open house that they are different moths than the gypsy moths,” she said.

“Unlike gypsy moths, they are natural to this area and I was told that their abundance recently is just part of their life cycles. I have no concerns with the spraying program.”



robert.barron@cowichanvalleycitizen.com

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Robert Barron

About the Author: Robert Barron

Since 2016, I've had had the pleasure of working with our dedicated staff and community in the Cowichan Valley.
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