The B.C. government is preparing to spray a non-harmful insecticide over parts of Surrey to deal with the city's gypsy moth invasion. 

Weather permitting, a low-flying plane will be delivering the first drop of Foray 48B over 62 hectares of residential and municipal park land on May 1. Two other sets of treatments are expected to follow at unspecified dates this spring.

According to the province, the use of aerial spray is necessary because previous attempts to attack gypsy moths by hand over the past two years failed to "eradicate" the pesky insects.

"It is now apparent that the ground sprays were not effective, likely due to limited site access," the Ministry of Forests said in a news release.

Gypsy moths are defoliators, meaning their caterpillars eat leaves, and the insects are considered a threat to fruit producers. They're known to munch on hundreds of different hosts, including apple trees and blueberry plants.

According to HealthLinkBC, the insecticide being used to attack the moths is "not toxic or harmful to people, dogs, cats, fish, birds, reptiles." It's also said to be safe for honeybees, beetles and spiders.

Foray 48B uses a bacterium called bacillus thuringiensis var kurstaki, which has been in use since the early 1960s and last year was approved for use on organic farms, according to the government.

But the ministry said it will be providing 24 hours' notice before each treatment so residents can make any preparations they deem necessary.

"Anyone wishing to minimize contact with the spray material may choose to remain indoors with their windows and doors closed during the spraying, and for at least 30 minutes after," it said.

Farmers with livestock may also want to consider bringing their animals inside so they aren't frightened by the fixed-wing aircraft.

The treatments are expected to start at around 5:20 a.m. and be completed by 7:30 a.m. daily.

Poor weather could force officials to reschedule the air drops on short notice.