A defoliating forest insect is building "almost in a circle around us," threatening both logging values and backyard trees, a provincial entomologist based in Kamloops said Friday.
While analysis is not yet complete, Lorraine MacLauchlan said there is evidence of rising Western budworm attack on fir trees close to the city.
"If you drive over the Coquihalla you get a sense - it's severe You walk into stands," she said. "You see defoliation and there's moths everywhere."
An agrologist who specializes in working with private landowners said some in the Paul Lake area were hit hard this year, something that threatens to be worse next year.
"I'm getting tons of phone calls," said Robson Rogan, with Purity Feed in Kamloops. "It's very evident to homeowners that, 'Oh my goodness, something is happening.'"
Budworm, like mountain pine beetle, is a naturally occurring pest.
Damage to buds and needles is done in spring, when larvae emerge to feed. The insects transfer to a moth stage at this time of year, when they mate and lay eggs that will emerge next spring for feeding.
"The population (around Paul Lake) has built to a point where it's exploded," Rogan said. "A lot of jaws have dropped."
Budworms don't typically kill a tree in one year, but successive years may weaken and finally kill fir trees. At risk are fir and spruce.
Nicola Ranch manager Matt Williams fears that as much as 20 per cent of fir trees on private ranchlands north of Merritt along the Coquihalla Highway are dead as a result of budworm infestation.
"You see almost 100 per cent affected. You see tops are dead."
The ranch, one of B.C.'s largest, also lost timber to mountain pine beetle.
"Budworm is death by a thousand cuts. It happens over a period of time."
Williams said the ranch may be forced to undertake a logging program to salvage economic value, despite relatively low prices.
Unlike pine beetle, however, there is an effective way to reduce building populations. The province aerial-sprayed a record amount of forest this year with a naturally occurring bacterium, known commercially as Foray 48B.
The organically registered product affects only moth and butterfly larvae, according to the Ministry of Forests, Lands and Natural Resource Development.
The ministry sprayed 6,700 hectares in this area in June, including at Duffy Lake, Inks Lake and Pinantan Lake.
Maclauchlan said that effort here is set to expand along with building insect populations.
"We're already starting our planning for next year."
Likely target areas include west of the North Thompson River, south toward Logan Lake and Paul Lake.
The province's concern is maintaining mid-term timber supply, particularly after losses of pine. Budworm can slow growth of trees and also kill understorey fir that represent subsequent years of potential harvesting.
For private landowners, Rogan said the concern is "100 per cent esthetics and high-value trees."
In the South Okanagan, where infestation has been severe, "they've got these million-dollar properties on five acres and they'll be completely defoliated."
The ministry sprays only Crown lands.
Rogan said large landowners and community associations can undertake private spray programs in a bid to stop further damage next year. He warned, however, that planning for next year takes time.