Ambrosia beetles are a group of wood-boring beetles typically associated with stressed, weakened, or recently transplanted trees. These beetles cultivate certain fungi inside their galleries as a food source. As a result, their infestation can lead to the introduction of these fungi into trees, causing further harm or even death to the host tree.
Signs of an Ambrosia Beetle Infestation:
- Frass Tubes or Toothpicks: These are recognizable structures protruding from the bark, made of compacted sawdust, resulting from female beetles boring into the tree.
- Entry Holes: Ambrosia beetles create small, round holes when they bore into the tree. These holes are typically between 1-2mm in diameter.
- Staining Around Entry Holes: The fungi introduced by ambrosia beetles can cause staining around these holes, indicating fungal growth inside the tree.
- Internal Streaking or Staining: Cutting into an infested branch may reveal black or dark streaking in the wood due to fungal growth within the beetle’s galleries.
- Wilting or Dieback: Infested trees might show signs of stress, particularly if the introduced fungal pathogens damage vascular tissues.
- Ambrosia Fungus: Within the galleries, you might find the ambrosia fungus, which appears white, cream, or gray with a powdery consistency.
- Presence of Beetles: Adult beetles are small but can sometimes be spotted around entry holes or on the trunk, especially during active periods.
- Decline in Tree Health: Trees heavily infested or already stressed might show a rapid decline in health due to the combined effects of boring damage and fungal infection.
If you suspect an infestation, it’s crucial to consult with Arborscapes for accurate diagnosis and management recommendations.
Of course, prevention and treatment for ambrosia beetles is included in a Plant Health Care subscription from Arborscapes. (As are myriad other pests and diseases) If you would like to become a part of our Plant Health Care program, reach out to Arborscapes today! Your living landscape will be the envy of the entire neighborhood!
Chris is a Board Certified Master Arborist, Tree Risk Assessment Qualified, a North Carolina Licensed Landscape Contractor, Registered Consulting Arborist and a member of the American Society of Consulting Arborists. He has has 20+ years of experience in the industry, and currently serves as Vice President of the Southern Chapter of the ISA.