Agrilus planipennis Fairmaire 1888
Exotic Emerald Ash Borer (EAB), Agrilus planipennis, reported in the United States and Canada
Name: Agrilus planipennis Fairmaire 1888
Animalia: Arthropoda: Insecta: Coleoptera: Buprestidae
Common Names: Emerald Ash Borer
An exotic beetle newly discovered in North America causes significant damage to ash (Fraxinus spp.) trees.
Issues of Concern:
The Emerald Ash Borer is an Asian Buprestid beetle. In June of 2002 the beetle was first detected on various ash (Fraxinus spp.) trees in five southeastern Michigan (MI) counties. Michigan reported mortality of green ash (Fraxinus pennsylvanica), white ash (F. americana), and black ash (F. nigra) trees in a 70 X 70 mile radius. Shortly after the Michigan detections, EAB was also detected on ash trees in Ontario, Canada.
Detection of infested trees is very difficult until external signs and symptoms are evident. Early detection of recently infested trees relies on inspectors removing bark sample to look for larvae and larval galleries. Surveys suggest EAB has been established in SE Michigan for approximately six years. EAB can attack and kill stressed and healthy ash trees. Its native host range (Asia) and establishment in the Great Lakes Area suggest EAB could survive in the majority of eastern North America.
EAB is now found in 13 Michigan counties, four Ohio counties, and Ontario, Canada. One county in Maryland reported an introduction of EAB from infested nursery stock and is now surveying surrounding areas for recovery of any potentially infested trees (Sept 5, 2003 News Story).
Pathways: Larvae of EAB are found in the cambial region of ash trees. In this area between the phloem and sapwood they overwinter and build extensive feeding galleries. Possible pathways for EAB introduction into uninfested areas include solid wood packing material (especially those not debarked), movement of ash tree nursery stock, woodchips, and firewood.
Hosts: White ash (Fraxinus americana); Green ash (F. pennsylvanica); Black ash (F. nigra); European ash (Fraxinus excelsior); Oriental ash (F. chinensis, F. rhynchophylla); various ornamental varieties [Ash (F. mandshurica var. japonica), Elm (Ulmus davidiana var. japonica), Walnut (Juglans mandshurica var. sieboldiana), and Wingnut (Pterocarya rhoifolia)]. Currently, only Fraxinus species have been reported as hosts within North America.
Vector(s)/Dispersal: The EAB belongs to a family of wood boring beetles known to transmit phytopathogenic fungi. At this time the sampled findings of A. planipennis are negative for phytopathogenic fungal transmission.
Indigenous to Asia (China, Korea, Japan, Mongolia, the Russian Far East, and Taiwan)
Quarantines: Michigan: Michigan Dept.Michigan: Michigan Dept. of Agriculture placed a quarantine on the movement of ash trees, limbs, firewood, logs, and untreated ash lumber from regulated areas. Current regulated areas in Michigan are Genesee, Ingham, Jackson, Lapeer, Lenawee, Livingston, Macomb, Monroe, Oakland, Shiawassee, St. Clair, Washtenaw, and Wayne counties (Nov 13, 2003).
Canada: The Canadian Food Inspection Agency has been conducting EAB surveys in Ontario and imposed a Ministerial Order in 2002. For updates to the Canadian regulations and a description of the area covered by the Ministerial Order see: http://www.inspection.gc.ca
Ohio: Ohio Dept. of Agriculture has placed a quarantine on ash trees, firewood, branches, and logs from Defiance and Wood counties (Nov 13, 2003).untreated ash lumber from regulated areas. Current regulated areas in Michigan are Genesee, Ingham, Jackson, Lapeer, Lenawee, Livingston, Macomb, Monroe, Oakland, Shiawassee, St. Clair, Washtenaw, and Wayne counties (Nov 13, 2003).
Canada: The Canadian Food Inspection Agency conducted EAB surveys in Ontario and by Ministerial Order deemed the city of Windsor, towns of LaSalle, Essex, Amherstburg, and Tecumseh quarantine areas (Sept 17, 2002).
Ohio: Ohio Dept. of Agriculture has placed a quarantine on ash trees, firewood, branches, and logs from Defiance and Wood counties (Nov 13, 2003).
Ash trees of all sizes and vigor are susceptible to EAB. Compromised trees are likely to be an easier target for the beetle although healthy trees will also be readily attacked. S-shaped, frass filled larval galleries occur beneath the bark of all infested trees. Vertical bark cracks over larval galleries and epicormal shoot growth are often present on infested trees. These bark cracks are more noticeable on younger trees with thinner bark. D-shaped exit holes on branches and trunks will only occur on trees that have been infested for at least one year. Thinning of the crown followed by crown dieback and tree mortality are indications of severely infested trees.
EAB adults are larger and a more brilliant green than any native North American Agrilus species. Adults are 7.5 to 13.5 mm long with females dominating in size. Depending upon local temperatures, adults will emerge from mid May to August and feed on foliage during warm sunny days in protected areas. Feeding damage is minimal. Recent reports suggest EAB can naturally disperse more than six miles from the host tree, compared to the previous reports of only a quarter mile (See news article). Oviposition occurs from late May through August. Eggs are generally found in bark crevices on the sun exposed side of trees. Larvae are cream colored, 10 to 14 mm in length, and feed on the sapwood and phloem of the tree until mid-October. The life cycle is one year with potential for two years in colder regions.
Michigan State University Pest Alert Webpage
USDA Forest Service Emerald Ash Borer Homepage
USDA Forest Service Northeastern Area Pest Alert for August 2002
Newsletter of the Michigan Entomological Society Vol.47 (3 & 4) September 2002
Canadian Food Inspection Agency report on EAB in Canada