Surrey has a moth problem.

Gypsy moths are an introduced pest that damage forests, farms and orchards, the province said in a statement Wednesday.

Caterpillars have been blamed for stripping leaves off trees and shrubs in forests and on residential properties in eastern Canada and the U.S. and can easily spread through cars, ships, trains and other modes of transportation.

If untreated, the moths could impact local agricultural and horticultural businesses, the Ministry of Forests, Lands, Natural Resource Operations and Rural development said.

They can cause extensive damage, and due to the risk, B.C.'s major trading partners could consider quarantines or restrictions on B.C. products including logs. This has happened before, 20 years ago, when the U.S. threatened to refuse shipments of B.C. trees without inspection certificates. 

The moths are also known to snack on leaves from apple trees and other fruit-bearing trees and plants, meaning they threaten B.C. fruit producers.

In an effort to stop the spread of the destructive species, the ministry will be spraying 62 acres of residential and municipal land in North Surrey in May and June. Clear evidence of gypsy moths has been found in an area near Highway 1 by the Port Mann Bridge.

A map of the area and details of the permit application is available online

The area was previously sprayed from the ground in 2017 and 2018, but it appears that method was not effective.

The insecticide is meant to kill the moths' larvae, minimizing the risk they pose to local farms and forests.

The ministry has been issued a pesticide-use permit to spray the area by helicopter as many as four times. The substance used, Foray 48B, is used in organic farming and contains bacillus thuringiensis (Btk), the province says.

Btk has been approved for use on gypsy moths in Canada since the 1960s, and is naturally present in soils in B.C.

"It does not harm humans, mammals, birds, fish, plants, reptiles, amphibians, bees or other insects and only affects caterpillars after they have ingested it," the ministry statement said.

Exact dates of the treatment will be determined by the weather, and will be announced closer to the two-month window. All spraying will be done before 7:30 a.m.

They arrived in North America from Europe in the 1860s, and were first noted in B.C. in 1978.