If you live in New York, chances are you’ve heard the Asian longhorned beetle is an invasive, wood-boring insect that seriously threatens hardwood trees across North America and Europe. Originating in China and Korea, the ALB has the potential to kill millions of trees, which makes early detection and reporting / remidiation important in stopping them.
Physical Characteristics
What to Look For:
- Adult Beetles: ALBs are giant beetles, measuring 1-1.5 inches long, with shiny black bodies covered in irregular white spots and distinctively long antennae, often exceeding 3.5 inches. The beetle’s feet may also have a blue tint.
- Antennal Bands: Their antennae’s black and bluish-white banding is one of their most unique features, making them easy to identify compared to native beetles.
Life Cycle and Behavior
Understanding the ALB’s Lifecycle:
- Stages: ALB undergoes a full metamorphosis, progressing from egg to larva, then pupa, and finally adult.
- Egg Laying: Females chew pits into the bark of host trees to lay 30-90 eggs during their lives, depositing each egg in a separate pit.
- Larval Feeding: After hatching, larvae burrow into the tree, feeding on the inner tissues and disrupting the tree’s ability to transport nutrients and water. This causes severe internal damage, eventually girdling and killing the tree.
- Adult Emergence: Adults typically emerge from late spring to late summer, with the peak season from June to August. Though they overwinter in various stages, adults do not survive the winter months.
Host Trees and Damage
Tree Species at Risk:
- ALB attacks a variety of hardwood trees, including maple, birch, elm, ash, poplar, willow, and horse chestnut. Even healthy trees are vulnerable, making the ALB especially destructive.
Signs of Damage:
- Round Exit Holes: Adult beetles create perfectly round exit holes, around ⅜ to ½ inches in diameter.
- Egg-Laying Sites: Small pits or depressions in the bark indicate where females have laid eggs.
- Sap and Frass: Sap may ooze from wounds in the bark, and a sawdust-like substance called frass often accumulates around the tree’s base or branch junctions.
- Tree Decline: Due to internal damage, infested trees may show wilting leaves, canopy dieback, and limb breakage. Complete tree death usually occurs within 7-9 years of the initial infestation.
Spread and Impact
- Introduction and Spread: First detected in North America in 1996 in New York, the ALB has since spread due to the movement of infested wood materials. Quarantines are often in place to restrict this spread.
- Economic and Ecological Threat: The ALB could kill up to 30% of urban trees in the U.S., with economic impacts estimated in the billions due to the loss of shade, aesthetic value, and ecosystem services.
Detection and Management
If You Suspect an Infestation:
- Document the Evidence: Photograph any beetles or signs of infestation, including a reference object for scale.
- Record the Location: Note the tree’s location with landmarks, nearby intersections, or GPS coordinates.
- Report: Contact local authorities via phone or report sightings online.
Preventative Measures for Homeowners:
- Avoid Moving Firewood: Firewood can transport ALB larvae, so it’s best to buy firewood locally and burn it on-site.
- Comply with Quarantine Rules: Follow local regulations on moving wood products from quarantined areas.
- Monitor Pool Filters: When cleaning pools, check filters for potential ALB beetles and report any suspicious finds.
- Choose Non-Host Trees: Consider planting tree species not favored by ALB to reduce the risk of infestation.
Important Considerations
- Tree Removal: There is currently no treatment for ALB-infested trees. Removing and destroying affected trees is the only way to control the spread.
- Stay Informed: Regularly check local resources for updates on ALB and potential sightings in your area.
- Cooperate with Officials: Allowing access to your property for inspections can help detect and manage infestations early.
