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Forest Disturbance Processes

The Biology of the European Oak Borer: A recently discovered exotic insect in North America

Research Issue

[photo:] Adult European oak borer.  Photo by by Eduard Jendek, CFIA, Ottawa, Ontario, Canada.  Used with permission.The European oak borer (EOB), Agrilus sulcicollis, was first discovered in North America in 2008, with populations being found in Michigan and Ontario, Canada.  Evidence was later found to prove that EOB had been present in North America for well over a decade, prior to its initial discovery, given that some previously collected specimens were subsequently identified that dated back as far as 1995 in Ontario and 2003 in Michigan.  The current known distribution of EOB in North America includes 10 counties in southern Michigan, as well as 2 counties in New York, and 6 counties in Ontario, Canada.   Intensive delimiting surveys were never conducted for EOB so its range in North America is likely much larger.  Given that EOB is exotic and is closely related to the emerald ash borer (Agrilus planipennis), its initial discovery raised considerable concern on what impact it may have on North American oaks (Quercus) especially when combined with the native twolined chestnut borer (Agrilus bilineatus, TLCB) as well as other oak pests. 

[photo:] Tree damaged by European oak borer.  Photo by Toby Petrice, USFS Northern Research Station.Our Research

Several studies were conducted on the life history of EOB in North America and the impacts it may have on oak trees.  We studied the flight period of adult beetles, attraction of adult beetles to different colored sticky traps, and host preference.  Comparisons were made with the native twolined chestnut borer (TLCB), Agrilus bilineatus.  

Research Results

We found that EOB has a life history similar to TLCB, in that mature overwintering larvae pupate in spring, adults emerge a few weeks later and lay eggs during summer.  Larvae hatch from eggs and tunnel to the cambial region where they feed through the summer and fall.  EOB adults emerge and fly a few weeks earlier compared to TLCB.  Adult EOB are attracted to purple and white sticky traps.  EOB attacked all oak species we tested including black oak (Q. velutina), English oak (Q. robur), northern red oak (Q. rubra), and white oak (Q. alba).  However, EOB prefers to attack very weakened or recently dead trees, while the more aggressive TLCB attacked much healthier, but usually stressed, trees in our study.  We also identified morphological characters for distinguished EOB larvae from TLCB larvae.  Results were published in Petrice and Haack (2014).

Petrice, T.R.; Haack, R.A. 2014. Biology of the European oak borer in Michigan, United States of America, with comparisons to the native twolined chestnut borer. The Canadian Entomologist 146: 36-51. doi:10.4039/tce.2013.58.

Haack, R.A.; Petrice, T.R.; Zablotny, J.E. 2009. The first report of the European oak borer, Agrilus sulcicollis (Coleoptera: Buprestidae), in the United States. Great Lakes Entomologist 42: 1–7.

Haack, Robert A.; Acciavatti, Robert E. 1992. Twolined chestnut borer. U.S. Dept. of Agriculture, Forest Service, Northern Area State & Private Forestry,[Broomall, PA, Forest Insect & Disease Leaflet 168.

Research Participants


Last Modified: November 20, 2014