Emerald Ash Borer Switching Hosts

The Emerald Ash Borer (Agrilus planipennis), an invasive pest once thought to only target ash trees, appears to be able to utilize a wider variety of trees as hosts. A researcher at Wright State University, Professor Don Cipollini, has found that the green beetle will also attack white fringetree, commonly known as Monrovia (Chionanthus virginicus) (Cipollini and Peterson, 2018). Cipollini was examining some white fringetrees in southwestern Ohio and discovered the tell-tale signs of an emerald ash borer: a D-shaped exit hole. This observation makes the white fringetree the second non-ash EAB host. In 2017, EAB was also observed successfully completing development to adulthood on a major cultivar of olive after its cut stems were inoculated with EAB eggs (Cipollini et al., 2017).

A close-up photo of a white fringetree taken in Maryland (Photo credit: Flickr).

In addition to the threat it poses to native Oregon ash (Fraxinus latifolia) and other ash species planted around the state, EAB’s ability to utilize cultivated olive as a host is another reason for Oregonian’s to be concerned. While still fairly young, the olive industry is growing in the state of Oregon.

It is estimated that the emerald ash borer will have caused $10 billion in economic damage by 2019 across the United States. Now that there is a new potential host for the insect, the extent of the issue could be more devastating than previously understood.

Literature Cited
Cipollini, D., C.M. Rigsby, D.L. Peterson. 2017. Feeding and Development of Emerald Ash Borer (Coleoptera: Buprestidae) on Cultivated Olive, Olea europaea. Journal of Economic Entomology: 10(4). 1935-1937. https://doi.org/10.1093/jee/tox139

Cipollini, D. and D.L. Peterson. 2018. The potential for host switching via ecological fitting in the emerald ash borer‐host plant system. Oecologia (2018) 187:507–519. https://doi.org/10.1007/s00442-018-4089-3