Blog & News

Emerald Ash Borer, (Agrilus planipennis) – not found on PEI yet! (archive)

Published on Saturday March 14, 2015
Authored by PEIISC


The emerald ash borer attacks and kills all species of ash, except mountain ash which is not a true ash. With artificial spread, where people move infested ash materials and firewood to new areas, this insect can quickly spread to other areas of Canada.

Federal regulatory measures prohibit the movement of specific materials including any ash material and firewood of all species from specific areas of Ontario and Quebec. Anyone violating these restrictions is subject to a fine and/or prosecution.

Slowing the spread of emerald ash borer will protect Canada’s environment and forest resources. It also helps keep international markets open to the forest industry and nurseries in non-regulated parts of Ontario and Quebec and in the rest of Canada.

Life Cycle:

The emerald ash borer life cycle can occur over one or two years depending on the time of year of oviposition, the health of the tree, and temperature. Adult beetles are typically bright metallic green and about 8.5 millimeters (0.33 in) long and 1.6 millimeters (0.063 in) wide. Underneath the elytra, the upper side of the abdomen is coppery-red, which is a distinctive feature of the species. After 400-500 accumulated growing degree days (GDD) at base 10 C (50 F), adults begin to emerge from trees, and peak emergence occurs around 1000 GDD. After emergence, adults feed for one week on ash leaves in the canopy before mating, but cause little defoliation in the process. A typical female can live around six weeks and lay approximately 40-70 eggs, but females that live longer can lay up to 200 eggs. Eggs are deposited between bark crevices, flakes, or cracks and hatch about two weeks later. Eggs are approximately 0.6 to 1.0 millimeter (0.024 to 0.039 in) in diameter, and are initially white, but later turn reddish-brown if fertile. After hatching, larvae chew through the bark to the phloem and cambium where they feed and develop. Emerald ash borer has four larval instars. By feeding, larvae create long serpentine galleries. Fully mature fourth-instar larvae are 26 to 32 millimeters (1.0 to 1.3 in) longIn fall, mature fourth-instars excavate chambers in the sapwood or outer bark where they fold into a J-shape. These J-shaped larvae shorten into pre-pupae and develop into pupae and adults the following spring. To exit the tree, adults chew holes from their chamber through the bark, which leaves a characteristic D-shaped exit hole. Immature larvae can overwinter in their larval gallery, but can require an additional summer of feeding before emerging as adults the following spring.

Control Options:

1. Remove and dispose of dead and dying Ash, in particular ash with Emerald Ash Borer symptoms. Contact Island Waste Watch for disposal locations for this invasive species.

2. TreeAzin injections.

3. Keep Trees as healthy as possible through selecting the appropriate planting site for various ash species. Avoid planting trees in areas where they will be stressed or compromised. Keep trees healthy through watering and fertilization as needed.

– David Carmichael, PEIISC Member and Landscape Technician with PEI’s Department of Agriculture and Forestry

Attached images:

Emerald ash borer adult. Image source: CFIA
Emerald ash borer larva. Image source: David Cappaert, Michigan State University
Emerald ash borer larvae galleries beneath bark Image source: Troy Kimoto, CFIA
Galleries and D-shaped exit holes from emerald ash borer. Image source: CFIA
Declining ash tree infested with emerald ash borer. Often tree will sucker on the lower trunk with a thinning in the upper canopy. Image source: Ches Caister, CFIA