Agrilus planipennis

Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Arthropoda
Subphylum	Hexapoda
Class	Insecta
Subclass	Pterygota
Infraclass	Neoptera
Order	Coleoptera
Suborder	Polyphaga
Infraorder	Elateriformia
Superfamily	Buprestoidea
Family	Buprestidae
Subfamily	Agrilinae
Tribe	Agrilini
Genus	Agrilus

Scientific Name

Agrilus planipennis

Common Name

emerald ash borer

Author: Joseph LaForest, University of Georgia

Overview

Origin: Emerald ash borer, Agrilus planipennis, is an invasive borer from northeast Asia threatening North American ash trees (Fraxinus).
Life Cycle: Females lay eggs 2 weeks after emergence. Eggs are initially light-yellow, turning to brownish-yellow before hatching. Eggs hatch in 1-2 weeks, and the tiny larvae bore through the bark and into the cambium and phloem. The creamy white larvae are 1–1.25 in. (2.5-3.2 cm) long with flat, broad, segmented bodies. Adults begin emerging in mid-June leaving 0.1–0.2 in. (0.25-0.5 cm) “D” shaped emergence holes. The life cycle in Michigan takes between 1-2 years depending on the climate. Larvae feed on phloem and make serpentine galleries that girdle and kill trees when the larval densities are high. Mature larvae tunnel into sap wood to pupate. In northern areas (e.g., Michigan), a single generation may require two years, but in mid-Atlantic states (e.g., Maryland), a generation can be completed each year.
Distribution: It was first detected near Detroit, Michigan and likely was introduced in the 1990s. It is now found in 14 other states and two Canadian provinces, and the infested range is expanding rapidly. Emerald ash borer attacks and kills healthy ash trees from ones several inches in diameter to mature trees. Massive mortality to ash of several species has occurred since the species' invasion in both landscape plantings and natural ash-dominated communities, especially in riparian areas.
Control Efforts: Three species of biocontrol have been researched and are currently being deployed. They include Spathius agrili (Hymenoptera: Braconidae), Oobius agrili (Hymenoptera: Encyrtidae), and Tetrastichus planipennisi (Hymenoptera:Eulophidae). This is a long-term management method rather than one targeted at immediate control. In dense populations, woodpeckers consume many larvae.

Distrubution

Emerald ash borer (EAB) is native to Asia. It has been found in Michigan, Illinois, Indiana, Iowa, Kentucky, Maryland, Minnesota, Missouri, New York, Ohio, Pennsylvania, Tennessee, West Virginia, Wisconsin, Ontario and Quebec. EAB probably arrived in the United States on solid wood packing material from Asia.

Host Range

Hosts include all ash (Fraxinus spp.) species; however, green ash, white ash, and black ash are more susceptible than Asian varieties.

Pathways and modes of spread

Emerald ash borer can easily be spread through the movement of infested live ash trees, limbs, firewood, logs, and untreated ash lumber.

Identification

It is a small, brassy-green, metallic wood-boring beetle measuring 1/3 to 1/2 inches in length. Larvae have bell-shaped segments with two dark spines at the tip of the abdomen. These are urogomphi and are diagnostic for larvae in the genus Agrilus.

Life cycle

Females lay eggs 2 weeks after emergence. Eggs are initially light-yellow, turning to brownish-yellow before hatching. Eggs hatch in 1-2 weeks, and the tiny larvae bore through the bark and into the cambium and phloem. The creamy white larvae are 1 – 1 1/4 inches long with flat, broad, segmented bodies. Adults begin emerging in mid-June leaving 0.1 – 0.2 inches “D” shaped emergence holes. The life cycle in Michigan takes between 1-2 years depending on the climate.

Plant Response and Damage

Some irregular notching may be observed on the foliage as the newly emerged adults will feed on it. Larvae feed in the cambium creating S-shaped frass-packed tunnels. Vertical splits in the bark are created by the tree forming callus tissue in response to larval feeding. The damage by the larvae causes general yellowing and thinning of the foliage followed by crown dieback and the eventual death of the tree. Basal sprouting and the presence of woodpeckers may indicate wood-boring beetle activity. After 1 to 2 years of infestation, the bark often falls off in pieces from damaged trees, exposing the insect galleries.

Monitoring

Survey techniques include visual surveys, attractant-baited panel traps, and destructive sampling. Since it is possible to have no visible signs or symptoms in the first year of an infestation, visual surveys are helpful for locating older infestations. The panel traps have proven more effective for detecting early infestations since ti traps the adults as they are flying to new host trees. Traps should be placed when in early to mid june when adult emergence and flight is expected. Destructive sampling is performed in areas where a new infestation is suspected. This type of sampling is best done in late summer or early fall since larvae should be large enough to locate and identify.

Management Approaches

Biological Control

Three species of biocontrol have been researched and are currently being deployed. They include Spathius agrili (Hymenoptera: Braconidae), Oobius agrili (Hymenoptera: Encyrtidae), and Tetrastichus planipennisi (Hymenoptera:Eulophidae). This is a long-term management method rather than one targeted at immediate control.

Chemical Control

Although there are chemical controls available for use over wide areas, several products have been tested for protection of individual trees.

Professional Use Products
INSECTICIDE FORMULATION	ACTIVE INGREDIENT	APPLICATION METHOD	TIMING
Merit (75WP, 75WSP, 2F)	Imidacloprid	Soil injection or drench	Mid-fall and/or mid- to late spring
Xytect (2F, 75WSP)	Imidacloprid	Soil injection or drench	Mid-fall and/or mid- to late spring
IMA-jet	Imidacloprid	Trunk injection, Arborjet	Early May to mid-June
Imicide	Imidacloprid	Trunk injection, Mauget	Early May to mid-June
Pointer	Imidacloprid	Trunk injection, Wedgle	Early May to mid-June
Inject-A-Cide B	Bidrin	Trunk injection, Mauget	Early May to mid-June
TREE-age	Emamectin benzoate	Trunk injection, Arborjet	Early May to mid-June
Safari (20 SG)	Systemic bark spray	Early May to mid-June
Astro	Permethrin	Preventive bark and foliage cover sprays	2 applications at 4-week intervals; first spray should occur when black locust is blooming
Onyx	Bifenthrin	Preventive bark and foliage cover sprays	2 applications at 4-week intervals; first spray should occur when black locust is blooming
Sevin SL	Carbaryl	Preventive bark and foliage cover sprays	2 applications at 4-week intervals; first spray should occur when black locust is blooming
Tempo	Cyfluthrin	Preventive bark and foliage cover sprays	2 applications at 4-week intervals; first spray should occur when black locust is blooming
Homeowner Products
Bayer Advanced Tree & Shrub Insect Control	Imidacloprid	Soil drench	Mid-fall or mid- to late spring

Not all treatments are as effective as others and some are not recommended in certain situations. Contact your local extension service for chemical control recommendations specific to your state and particular situation. Results of some tests have also been posted on EmeraldAshBorer.info.

Agrilus planipennis

Taxonomy

Scientific Name

Common Name

Contents

Overview

Distrubution

Host Range

Pathways and modes of spread

Identification

Life cycle

Plant Response and Damage

Monitoring

Management Approaches

Biological Control

Chemical Control

Image Gallery

References