Agrilus planipennis

Emerald Ash Borer
Agrilus planipennis

Emerald Ash Borer Agrilus planipennis on Ash leaf. June 22, 2007. Wheatley, Ontario.
Emerald Ash Borer Agrilus planipennis on Ash leaf. June 22, 2007. Wheatley, Ontario.

Identification: Exotic, invasive species native to Russia, Northeast China, Korea and Japan. Entered southeast Michigan (Detroit area) about 1992 by pallets and wooden crates. Discovered in Windsor, Ontario by 2002. Spread to Quebec and 15 states in U.S. These beetles kill Ash Fraxinus trees. More exotic insects under the name “Biological control agents” have recently been imported from China in an attempt to control the spread of this invasive pest.

Head: Bright metallic green with copper reflections. Indented down middle from top of head to mid face. Eyes long, wrapping up to top of head.

Emerald Ash Borer Agrilus planipennis mating on Privet Hedge below Ash tree. June 28, 2008. Wheatley, Ontario.
Emerald Ash Borer Agrilus planipennis mating on Privet Hedge below Ash tree. June 28, 2008. Wheatley, Ontario.

Antenna: Gray with greenish reflections. Segments 4 to tip are steak-knife-like (serrated).
Thorax (Pronotum): Bright metallic green with copper reflections. Wide or narrow indented area down middle of entire length. Base margin wraps around sides of head, each end pointed. The side margins slant upward to base of wings, with an upturned or shelf edge which is slightly wavy and somewhat lighter in colour. Lower margin is very sharply waved, the V-shape at margin center is notched at tip. No hair, but male has some on the underside.
Wings (Elytra): Bright metallic dark green, usually no copper reflections, but sometimes has lighter areas along sides and lower half of wings. Wings are very long and narrow, with long, slightly rounded tips. Base margin of wings wide and shaped to conform with lower margin of thorax. Sides are slightly indented or wavy; margin widens and is lighter in colour to about mid wing. No hair. Center of base margin (scutellum) very small, triangular to rounded; same colour.

Emerald Ash Borer Agrilus planipennis showing metallic reddish-purple abdomen. June 14, 2091, Thamesville, Ontario
Emerald Ash Borer Agrilus planipennis showing metallic reddish-purple abdomen. June 14, 2091, Thamesville, Ontario

Legs: Metallic blackish-green, depending on light. Feet have one long claw.
Abdomen: Top (rarely seen) is metallic reddish-purple. Lighter metallic green on underside.

Similar Species: Bronze Birch Borer Agrilus anxius darker, more brownish.

Size: 10 to 14 mm (13 avg.)

Habitat: Forests and urban areas with Ash trees.

Food: Adults feed on Ash leaves.

Flight Time: Mid-June to August.

Emerald Ash Borer Agrilus planipennis tunnels from larva in Ash. April 05, 2010. Wheatley, Ontario.
Emerald Ash Borer Agrilus planipennis tunnels from larva in Ash. April 05, 2010. Wheatley, Ontario.

Life Cycle: Eggs are laid in bark crevasses and on branches of  White Ash Fraxinus americana, Black Ash Fraxinus nigra, Red or Green Ash Fraxinus pennsylvanica and the rare Pumpkin Ash Fraxinus profunda found in southwestern Ontario. Also uses White Fringetree Chionanthus virginicus native along U.S. east coast. Females can lay average of 75 eggs in their 3 weeks as adults. Males live only 2 weeks. Eggs turn from whitish to reddish-brown within 2 to 3 days, and hatch in about a week.

Emerald Ash Borer Agrilus planipennis D-shaped exit hole in Ash tree. April 05, 2010 Wheatley, Ontario.
Emerald Ash Borer Agrilus planipennis D-shaped exit hole in Ash tree. April 05, 2010 Wheatley, Ontario.

Larvae are flat-headed borers and chew through bark into the tree, creating U- or S-shaped tunnels. Mature larvae are creamy white, 26 to 32 mm long. Over-winters as mature larvae, pupating in April to early May near the beginning of the tunnel. Pupa are also creamy white, 10 to 14 mm long. After hatching, they stay in the tunnel to harden up, then chew a D-shaped exit hole about 4 mm. wide.

Parasites: The Beewolf Beetle Wasp Cerceris fumipennis captures adults as food for her young. Braconid Wasp Spathius agrili, and Chalcid Wasps Tetrastichus planipennisi and Oobius agrili have been imported from China and released around 2002 to present. About 75,000 or more to 2012. Survey work done in 2013 found that these parasites did not survive. However, another Chalcid Wasp, native of Asia was discovered by Gibson in 2005 in West Virginia called Balcha indica, and it did survive. No mention of exactly how and when this wasp entered the U.S.

Comments: Essex County; Ontario, Quebec.

 
For information on synonyms, references and type specimens see next page

Leave a Reply