B.C. targets invasive moths with sweeping insecticide spray on Vancouver Island

Government of B.C.

The B.C. government is planning to spray hundreds of hectares of Vancouver Island with a biological insecticide to help reduce the spread of invasive spongy moths.

The aerial treatments occur every year on Vancouver Island, and are intended to kill spongy moth caterpillars and larve who feed on leaves and have destroyed sections of forests in Ontario and the Eastern United States, according to the province.

In B.C., the provincial government says it’s concerned about protecting forests, farms, orchards and trees – with large sprays planned for North Saanich, Greater Victoria, Cowichan Bay, Nanaimo and Qualicum Beach this spring.

“Untreated spongy moths risk spreading to other areas of B.C. and are a threat to urban forests and farms,” said the province in a release Wednesday.

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Three aerial sprays are planned between late April and mid-June, depending on weather conditions.

Each spray could take up two days to complete, and the sprays will be spaced out about seven to 10 days apart.

The sprays will take place at dawn and end no later than 7:30 a.m., according to the province.

Aerial treatments

B.C. will be using a biological insecticide called Foray 48B, which the province says is used in organic farming.

“The active ingredient Bacillus thuringiensis var kurstaki (BtK) is naturally present in urban, agricultural and forest soils in the province,” said the ministry of forests in its release Friday.

The insecticide only affects moth and butterfly caterpillars after ingesting it, and was first approved for use against spongy moth larvae in Canada in 1961, according to the province.

The sprays are planned for the following areas, though the province did not elaborate on specific locations in its release:

  • North Saanich: 170 hectares (ha)
  • Greater Victoria: Gorge-Tillicum: 120 ha; Esquimalt and Victoria West: 31 ha; Belmont: 430 ha
  • Cowichan Bay: 126 ha
  • Nanaimo: 130 ha
  • Qualicum Beach: 96 ha
  • Salt Spring Island: 48 ha
Adam Chan

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