Explanation of Names
Agrilus planipennis Fairmaire 1888
(L). 'flat wing' (1)
adult 7.5-14 mm (males smaller than females); larva up to 32 mm
Adult: elytra bright metallic green; pronotum golden-green; ventral surface lighter yellowish-green (with fine hairs in males, lacking in females); body narrow and elongate; head flat; eyes kidney-shaped, black; dorsal surface of abdomen metallic purplish-red, visible when wings are spread
generally larger and brighter green than native NA spp.
Larva: body white to cream-colored, dorso-ventrally flattened; head brown, mostly retracted into prothorax; abdomen 10-segmented with pair of brown pincer-like appendages on last segment; segments 5-8 widen posteriorly, giving the abdomen a serrated appearance when viewed from above
native to E. Asia, accidentally introduced to N. Amer., established around the Great Lakes (see distribution map
) and has spread as far as CO, TX, and GA.
spp. are classified as either the dominant or co-dominant species in 150 North American forest and shrubland communities (2)
mostly: May-July (BG data)
Laboratory trials suggest that all 16 species of North American Fraxinus spp. may be suitable hosts for larval development of EAB and thus are susceptible to attack (Anulewicz et al., 2008)
Tim Turner: In my experience as an ISA Certified Arborist working in the Dayton, Ohio area, EAB prefers Green Ash (F. pennsylvanica
) to White Ash (F. americana
) (and either of those to F. quadrangulata
, Blue Ash), not attacking the latter until the locally available Green Ash are clearly in decline (eventually they kill all three species of ash, but the Green Ash die first).
The only other Agrilus sp. that hosts on Fraxinus spp. (and hence has the same characteristic "D" shaped exit hole) is:
Agrilus subcinctus Gory
- Range: e US to NM
but note that A. subcinctus primarily hosts in recently dead ash twigs.
four instars take one to two years to develop; overwinters as larva in outer sapwood/bark; pupate in April-May; adults emerge in late spring through D-shaped exit holes; adults consume foliage before mating and flight; after hatching, larvae chew through outer bark and bore S-shaped tunnels in inner bark until late fall, then stop feeding.
accidentally introduced with imported packaging/crating wood, probably in the late 1990s; first reported in se. MICH
and sw. ONT in mid 2002. By the end of 2002, it was apparent that at least 5–7 million ash trees were declining, dying, or dead in a six-county area of southeastern Michigan. (Cappaert, et al., 2005) (Recent dendrochronological evidence indicates that A. planipennis
was established in southeastern Michigan at least 10 years before its discovery.)
the EAB is considered to be among the most destructive forest insect pests to have been introduced into North America (Herms and McCullough, 2014)
potential costs associated with removals of urban ash trees in the United States were estimated at $20–60 billion, a figure that does not include replacement costs. (Cappaert, et al., 2005)
distribution of A. planipennis among trees within forested areas is often heterogeneous. Heavily infested trees with abundant exit holes and almost complete dieback can be found adjacent to similar trees that remain healthy with little or no evidence of colonization by A. planipennis. (Cappaert, et al., 2005)
In surveying for EAB, it became evident that visual surveys were inadequate, especially for locating recent or low-density A. planipennis infestations. External symptoms on ash trees, such as crown dieback, bark splits, woodpecker attacks, and epicormic shoots, are rarely visible during the early stages of infestation. Characteristic D-shaped exit holes left by emerging adults are often difficult to find on large trees with thick, rough bark. Moreover, there was a clear tendency—across habitat types and for white and green ash—for early attacks to occur in the canopy, with colonization of the lower stem occurring only after tree decline and external symptoms are evident. (Cappaert, et al., 2005)
Although bark removal was time-consuming and expensive, it was a key aspect of the survey. More than half of the trap trees on which A. planipennis was detected had larvae but no adult beetles or external symptoms of infestation. (Cappaert, et al., 2005)
Girdled trap trees are proving to be more effective detection tools where A. planipennis densities are low, for example, at the leading edge of an infestation or in outlier populations where surrounding trees are relatively healthy and less attractive. (Cappaert, et al., 2005)
Although the use of girdled trap trees significantly improved the effectiveness of the survey and detection program in Michigan, the technique is labor intensive and destructive. (Cappaert, et al., 2005)
females are thought to rarely disperse more than 0.5 km from their emergence site. Early results suggest that dispersal in low-density outlier sites in Michigan has been less than 1 km/yr. (Cappaert, et al., 2005)
white ash (F. americana
) and, to a lesser extent, green ash (F. pennsylvanica
) are commercially important trees (2)
(white ash has long been the preferred wood for the Louisville Slugger – a bat popular with professional baseball players.)
saplings of white and green ash as narrow as 1 cm in diameter are exploited by the beetle and its immature stages (2)
once infested, tree death typically follows within 2 to 6 years (Knight et al., 2013)
98 spp. of ash-feeding arthropods are believe to be threatened by the emerald ash borer. (2)
(Crabronidae) is a wasp that preys on EAB
Anulewicz, A.C., D.G. McCullough, D.L. Cappaert, and T.M. Poland. 2008. Host range of the emerald ash borer (Agrilus planipennis Fairmaire) (Coleoptera: Buprestidae) in North America: results of multiple-choice field experiments. Environmental Entomology 37: 230–241.
Bauer, Leah S.; Duan, Jian J.; Gould, Juli R.; van Driesche, Roy; et al. (March 8, 2015). "Progress in the classical biological control of Agrilus planipennis Fairmaire (Coleoptera:Bupresitdae) in North America". The Canadian Entomologist. 147: 300–317.
Bauer, L.S.; Liu, H-P; Miller, D.; Gould, J. 2008. Developing a classical biological control program for Agrilus planipennis (Coleoptera: Buprestidae), an invasive ash pest in North America. Newsletter of the Michigan Entomological Society. 53(3&4): 38–39.
, D.G. McCullough, T.M. Poland, and N.W. Siegert. 2005. Emerald ash borer in North America: A research and regulatory challenge. American Entomologist Fall 2005: 152-165. (Full PDF
Duan, J.J. and J. Schmude. 2016. Biology and life history of Atanycolus cappaerti
(Hymenoptera: Braconidae), a North American larval parasitoid attacking the invasive emerald ash borer (Coleoptera: Buprestidae). Florida Entomologist 99(4): 722-728. (Full PDF
Herms, D.A. and D.G. McCullough. 2014. Emerald ash borer invasion of North America: History, biology, ecology, impacts, and management. Annual Review Entomology 59: 13–30.
Knight, K., J. Brown, and R. Long. 2013. Factors affecting the survival of ash (Fraxinus spp.) trees infested by emerald ash borer (Agrilus planipennis). Biological Invasions 15: 371–383.
Wagner, D.L. and K. Todd. 2015. Ecological impacts of the emerald ash borer. Pp. 15-62. In
: R.G. Van Driesche (ed.), Biology and Control of Emerald Ash Borer, USDA Technical Bulletin FHTET-2014-09. Morgantown, WV. (2)