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Spraying for gypsy moths in Sarnia now expected to begin May 20

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Journal Staff

City Hall says aerial spraying to control gypsy moths is now scheduled to begin on May 20, depending on weather and the development of moth larvae.

A second application will occur within 5 to 7 days of the first application.

Spraying was initially to begin May 15.

Gypsy moths, an invasive species whose caterpillars can quickly defoliate trees, attacked pockets of the urban forest last summer.

Sarnia has hired a company with a twin-engine helicopter to spray using a biological insecticide.

The target area is 64 hectares (157 acres), which includes Canatara Park and Lake Chipican Drive, Oak Acres Park, Lakeshore Road east of Modeland, and Colborne Road north of Michigan, south of Cathcart, and east to Errol Road and Ridgewood Drive.

The active ingredient in the spray is Bacillus thuringiensis v. kurstaki (Btk), a bacterium found naturally in soils and successfully used for 30 years as a biological pest control agent on wooded areas and agricultural crops, the city says.

For more on Btk visit the Government of Canada’s website:

Spraying in each of the four areas will take about 15 minutes and occur between 5 a.m. and 8 a.m., the city said.

The schedule will be posted at, and Facebook and Twitter prior to the spraying, which is highly dependent on weather conditions and subject to change.

Homeowners within the four spray areas will be sent a letter. Additional information can be found at


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