Bark Beetles in Mature Coast Redwoods: Treatment Strategy

Two 28-year, 75-ft coast redwoods show beetle boring: 1" dead branches with holes, frass at eye level. Arborist said Bayer Advanced soil drench may not reach roots (15-20 ft out) and eggs already laid. Owner considers selling for lumber.

Better Approach

• Spray trunk with Merit or Onyx insecticide as high as possible (pump sprayer reaches 20+ ft).
• Fertilize: 10-10-10 at 1 lb/inch trunk diameter, water in.
• Water deeply 1 inch weekly if no rain.

Don't Give Up

Beetles attack stressed trees. Green foliage = recovery possible. Redwoods valuable; exhaust treatment before removal.