This may be the fourth year in what is usually a four-year cycle of damage from the Douglas fir tussock moth, so it’s not expected there’ll be as much of a problem from it this year in Kelowna.
The city’s urban forest technician, Blair Stewart, says damage usually ebbs as a virus attacks populations of the devastating pest by the fourth year.
Tussock moth can strip a tree of all its needles as hundreds of the caterpillars chew them up. In turn, that larval stage of fuzzy worms can trigger an allergic reaction in both people and horses, with sometimes serious consequences.
He said he has found egg masses from the overwintering stage of the moth in the North Glenmore area, but even there he’s anticipating there will be less activity there this season.
Overall, he isn’t expecting large populations this year, particularly after some areas were sprayed last year. “Last year’s spray program was quite successful,” he said.
The cool and late spring weather the past two years and more-normal winters help to keep populations of such insect pests in check, he noted.
Normally, there’s a six to eight-year period between cycles, before the population again reaches damaging levels.