Scale Insects on Catalpa Tree in North Florida: Multi-Year Management Plan

The white, shell-like bumps on your catalpa trunk and branches are scale insects (likely armored scale). The dead main trunk suggests advanced infestation.

Why They're Hard to Control

• Waxy "shell" protects adults from contact insecticides.
• Only the mobile crawler stage (early spring) is vulnerable.
• Multiple generations per year in Florida.

Management Plan

1. Timing: Apply insecticidal soap or neem oil when crawlers are active (early spring). Check with UF/IFAS Extension for local dates.
2. Coverage: Spray to runoff—trunk, branches, twigs. Repeat 2–3× at 10–14 day intervals during crawler window.
3. Systemic option: Soil drench with imidacloprid (spring) — translocates to sap, kills feeding scales. Slower but thorough.
4. Prune out dead trunk and heavily infested branches.
5. Expect 2–3 years of consistent treatment for control.

Resources

• Insecticidal soap: livingwithbugs.com
• Neem oil: livingwithbugs.com
• Scale info: livingwithbugs.com

Persistence pays. The tree can recover if live cambium remains.