San Jose scale

Tiny circular scales cluster on twigs and branches of stone fruits in Western Washington, with a reddish area often developing at each feeding site and extending internally. Large populations cause tree vigor loss with thinning and yellowing of foliage. This introduced pest has been a potential orchard problem in our region for decades; infestations develop most readily in poorly managed orchards near ornamental or native hosts.

Well-managed orchards maintain populations below damaging levels through consistent monitoring and timely intervention. Inspect twigs in early spring and prune infested branches. Dormant oil spray in early spring coats emerging beetles. Remove dead wood and avoid stress conditions.