Pit scale

You will see small pits or depressions in oak bark created by scale insect colonies feeding beneath the bark surface. Pit scales are tiny and reddish. Heavy infestations create visible bark damage and pit scarring. Quercus species throughout Western Washington are susceptible. Damage is primarily cosmetic, with minimal impact on tree health.

No chemical control is warranted for this primarily cosmetic pest. Pit scale damage does not threaten oak health. Prune heavily scarred branches if appearance is important. Dormant oils may reduce populations if aesthetic concerns justify treatment. Natural enemies including parasitic wasps and mites control many populations. Maintain tree vigor.