EMERALD ASH BORER
Agrilus planipennis

Name and Family
History
Identification Guide
What it does in the ecosystem
Management
Image Gallery
References

Name and Family

Emerald Ash Borer, Agrilus planipennis, is a member of the buprestid/jewel beetle family (Buprestidae).

History

The Emerald Ash Borer (EAB) was introduced from Asia.
EAB was first detected near Detroit, MI and in Windsor, ON in 2002.
EAB likely arrived in wood packaging material in the early ’90’s. Since then it has spread to 15 U.S. states, across Southern Ontario and into Quebec.
EAB has not yet been detected on PEI.
Infested/regulated areas:
- The Emerald Ash Borer is rapidly spreading throughout our native ash tree’s geographic range.
- Areas where EAB is known to be present will come under federal regulation to limit the movement of wood materials in the area.
- Regulated infested areas include:
- Most of Southern Ontario, up to and including the Sudbury Area
- Most of Southern Quebec up to Gaspésie,
- The City of Winnipeg
- The City of Thunder Bay
- Southern New Brunswick,
- The greater Halifax region,
- Most of the Eastern half of the USA.

Identification Guide

Adult beetles are bright metallic green, with a coppery-red back (under wings)
Typically 8.5mm long and 1.6mm wide
Eggs are 0.6 – 1.0mm wide, and are initially white but later turn reddish-brown if fertile
Eggs are deposited between bark crevices, flakes or cracks, and hatch two weeks later
Adults create a D-shaped hole when exiting tree

HOST TREES

Fraxus spp., Ash trees.
- All native ash species are susceptible to EAB. EAB has only been detected on ash trees in North America.
NOTE: Trees in the Sorbus group, European and American Mountain Ash, are not “true” ash trees, and are unaffected by EAB.
- These trees do not require monitoring for EAB, but may still be affected by other pests and diseases.

DETECTION

If you have seen EAB on PEI, the PEI Invasive Species Council (PEIISC) wants to know about it.
- Report any sightings immediately to the PEIISC and your local Canadian Food Inspection Agency (CFIA) office.
- If possible, take photographs of the insect and any associated damage. Collect a specimen in a jar for identification purposes.
- As most outbreaks have started in urban areas, city dwellers should check out any ash trees on their property for signs of EAB activity.
- If you have a pool, check your filter regularly to see if any invasive insects, like EAB, have been collected there.

The PEIISC has been working with the CFIA, the City of Charlottetown, MacPhail Woods, and the Abegweit Conservation Society to monitor for EAB presence.
- We use Prism Traps mounted high up in priority ash trees to detect EAB.
- These are three-sided sticky traps that use an EAB sex pheromone and volatile compounds to attract the insect.
- Traps are regularly monitored for shiny green EAB adults.

“Trap trees” are frequently used in the monitoring and detection of EAB.
- These are specifically selected ash trees that are girdled.
- The tree should be otherwise healthy, between four and 10 inches in diameter, and located at a sunny place (like a roadside).
- Girdle the tree around chest height. The damage from girdling will cause the ash tree to release compounds that attract EAB to that ash tree specifically. The following year, the tree will be cut down and checked for the presence of EAB.

Branch sampling is another technique used to monitor for EAB presence in high-value and urban environments.
- This involves the removal of healthy branches in the crown of an ash tree that then are assessed by a professional for signs of damage caused by EAB infestation.

SIGNS AND SYMPTOMS:

Monitor any ash trees on your property for signs of EAB damage. Signs include:
- Sesame seed sized (approximately 3.5 – 4.1 mm), D-shaped exit holes
- Vertical splitting in the bark, called “bark cracking”
- Production of new young shoots at the base of the tree, called “epicormic shoots”
- S-shaped galleries from larval feeding on water-conducting tissues (this activity can create gaps that prevent the tree from moving water and nutrients through itself, called girdling)
- Canopy dieback, beginning in the tree’s crown
- Evidence of woodpecker feeding activity on the bark, called “blonding”.
- Scar tissue that appears as a lumpy or deformed mass. Called “callus formation”.
- Irregular notches in leaves from adult beetle feeding
- Sloughing off of bark.
- A keen eye is needed, as signs will often only become obvious after a tree has been thoroughly infested.

What it does in the ecosystem

The Emerald Ash Borer (EAB) is an invasive beetle that attacks and kills all species of ash trees, except mountain ash (which is not a true ash species).
EAB has killed over 99% of the ash trees it has infested in North America, making this pest exceptionally lethal.
As this species spreads throughout ash’s native range, it could lead to the functional extinction of native ash trees in North America.

Management

TAKING ACTION

At the Federal level, the focus has shifted away from the eradication of EAB within regulated areas. Now the focus is placed on preventing the further spread of EAB that would result in a reduction of fitness/health in established ash populations.

Trunk-injected professionally-applied insecticides exist and can act as a preventative measure for treating high-value ash trees.
- This is generally accepted as the most effective method to protect your ash trees.
- These insecticides travel from the base of the trunk throughout the tree, making it poisonous to wood-boring insects.
- Using a selective insecticide that targets EAB specifically can prevent unintended damage to populations of beneficial insects in the area.
- If the tree’s canopy is less than 50% affected, then treatment with properly regimented insecticides may save the tree.
  - With a greater than 50% loss of canopy, the tree has little hope of regenerating.
  - Some sources suggest that with more than 20% of the canopy affected, trees may be untreatable.
- Several insecticide treatments exist and are applied by a multitude of methods.
- Be sure to choose the right insecticide for the job, consult professionals, follow all manufacturer’s instructions, and adhere to all local legislation when applying insecticides.

For infested trees deemed unworthy of treatment, cut the affected tree down and put all parts into a chipper.
- Chip the tree into pieces no larger than one inch.
- Grind the stump.
- Before leaving, check and clean all clothing, equipment, and vehicles to ensure no EAB life stage (egg, larva, pupa, or adult) is transported offsite with equipment.
- Removed trees can also be burned or buried on-site if no chipper is available and if safety allows.
  - Burning may be prohibited seasonally or based on some other measured risk.
  - With any fire comes risks. Fire can spread quickly, especially during times of drought. It is important to assess the applicable safety risks associated with a burn before undertaking one.
  - Check out the provincial Fire Weather Index (FWI), active from March 15 – November 30, at this link Fire Weather Index (FWI) | Government of Prince Edward Island.
  - Burning will require a Domestic Burning Permit from the PEI Department of Environment, Energy, and Climate Action.
    - https://www.princeedwardisland.ca/fr/service/domestic-burning-permit-online-application

A new type of trap called FraxiProtec has been recently developed by GDG environment.
- This trap uses a fungus, Beauveria bassiana, that infects and kills EAB over time.
- The trap attracts and captures the insect, inoculates it with the fungus, and then allows it to leave, further dispersing the fungal spores.
- Affected EAB will gradually die from the fungal infection.
- This can be a fairly effective control method when used in conjunction with other management tactics.

BIOCONTROL

An effective biocontrol method is the release of parasitic wasps that are found in EAB’s native range.
- After significant research in collaboration with the USDA, four species of EAB-killing wasp have been approved for release in Canada, and three have been found effective in controlling EAB populations here.
- These wasps have been released by Natural Resources Canada Forestry Service at 19 sites in Quebec and Ontario, and are not available commercially for public dissemination.
- The parasites affect the various life stages of EAB.
- These wasps have been found capable of establishing themselves in the wild in North America.
- EAB density has been shown to have decreased significantly following a regiment of control that included parasitic wasp release.
  - It is difficult to determine whether this decline may be attributed to the relative decline in ash tree populations in those areas that occurred over the same period. Nevertheless, these results are promising!

POST-TREATMENT

After the removal of ash trees for control efforts, it is important to replant the area to fill the ecological niche left open and increase local biodiversity.
Without the replanting of native species, invasive plants may take advantage of the new space, causing further ecological damage.
Recommended native species to plant in place of removed ash trees include: