We’ve found no evidence of fresh infestation among our Ponderosa Pine growing where neighboring trees were killed last year by mountain pine beetles. The combination of cutting and peeling dying, infested “brood” trees and using Verbenone hormonal beetle repellant seems to have worked in this small area of less than 1 acre.
There are fresh infestations among trees about 300 yards above the treated area. Two trees inside a circle of beetle killed Ponderosa are loaded with pitch tubes. I’ll cut and peel these brood trees next year, and perhaps limit further spread.