Aloe Brown Tip Rot: Bacterial or Fungal?

Progressive Brown Rot on Aloe in Coastal SoCal

Two 2.5-ft aloes with brown tips spreading downward, tissue becoming limp then dry, suggest a bacterial soft rot (Erwinia, Pectobacterium) or fungal pathogen (Fusarium, Colletotrichum) entering through insect wounds or mechanical damage.

Diagnostic Clues

• Bacterial: Tissue turns mushy, watery, foul-smelling. Spreads fast in heat/humidity.
• Fungal: Dry, brittle, sunken lesions. May have concentric rings or sporulation.

Action Plan

1. Isolate affected plants.
2. Remove pups (offsets) from base—pot separately in clean mix.
3. Excise rotted tissue on mother plant back to firm, healthy green. Sterilize knife between cuts.
4. Dust cuts with sulfur/cinnamon.
5. Apply copper fungicide/bactericide (e.g., Monterey Liqui-Cop) to crown and soil.
6. Dry conditions: No overhead water. Bright light. Good airflow.

Vector Check

• Inspect for sucking insects (mealybugs, scale, aphids) that transmit bacteria.
• Treat with neem oil or insecticidal soap if found.

Photos to jdcawly@mckendree.edu can help ID the pathogen. Save the pups—they’re your insurance.