The Plant Pest Diagnostic Clinic (PPDC) received a phone call in September 2023 from a client in Summit County, Ohio saying that powdered dust was coming from a wooden figurine/nativity they purchased in December 2022. The client bought the figurine from a local shop in Bethlehem, Israel. With instructions provided, the client double-bagged the wooden figurine and brought it to the entomology department for observation. Upon receiving the figurine, it was kept in a -20C freezer in the PPDC for approximately 3 weeks to kill any insects in any life stages before extracting them for identification.
Active OBBs in the figurine (notice the fine dust piles).
The figurine was sealed inside a chamber after extracting the beetles.
After 3 weeks, the figurine was brought into the USDA APHIS-approved containment room in the entomology department, Wooster campus for investigation. We observed hundreds of tiny holes about 2-2.5mm in diameter all over it. Peeling the bark with a flat screwdriver, we extracted 13 dead beetles along with a few larval exuviae and head capsules. These insects were identified as Olive Bark Beetle, Phloeotribus scarabaeoides (Bernard, 1788).
Click here to read about the genus Phloeotribus in the US.
Findings were reported to USDA APHIS in Reynoldsburg, OH, and the collected beetles were sent to the National Identification Services (NIS) for confirmation. On 29 January 2024, the NIS confirmed that the insects were indeed P. scarabaeoides.
Entrance and exit holes of the adult OBB.
The main gallery and larval galleries in the olive bark.
Olive bark beetle is widely distributed in southern Europe, North Africa, and the Middle East, and has unique characteristics among the weevils (Family: Curculionidae). Adults are very small (2 - 2.5mm in length) with dark brown to black bodies that are densely covered with yellowish hairs. Sometimes the elytra are bi-colored. The pronotum is granulated with many hairs. The antennae contain the scape (first segment), 5 additional smaller segments, and a club with three movable segments called ‘pseudolamella’.
Click here to see a great resource of images of OBB.
OBB adults – Separable pseudolamelate (last antennal segment) and bi-colored elytra are unique characters to ID them.
OBB has been reported feeding on common Oleander (Nerium oleander - Apocynaceae), European ash (Fraxinus excelsior - Oleaceae), and common lilac (Syringa vulgaris - Oleaceae) throughout the Mediterranean region (CDFA, 2017). Some authors indicated this beetle also feeds on mastic (Pistacia lentiscus – Anacardiaceae), Phyllyrea spp. (Oleaceae), and Rhamnus alaternus (Rhamnaeae) in the Maltese islands (Mifsud & Knizek 2009). iNaturalist has records of mastic in California, Arizona, and Texas, but these have not been verified by experts. Although there are no records of OBB feeding on these host plants in the US, lilac is widespread in Ohio. If OBB arrives in the state and escapes, there is a chance that the beetles may establish using lilac as a host even in the absence of their preferred host, European olive (Olea europaea).
Olive is native to the Mediterranean region but is grown in several areas of California. All the olive species currently grown in California were brought from either Spain or Italy by the Missionaries in the 17th and 18th centuries. (READ MORE).
Adult females bore into the trunk of a host tree and excavate transverse galleries wherein they lay about 50-60 eggs. The emerging larvae make tunnels perpendicular to the main tunnel up and down the sapwood and enlarge the tunnel as they grow. This causes partial to complete girdling of the twig or branch, structurally weakening the tree. (READ MORE).
The first report of OBB in North America was in Riverside Co., California on 18 October 2016. In fact, this was the first record of OBB in the Western Hemisphere. California Department of Food and Agriculture (CDFA) finalized a report in 2017 indicating that OBB was expected to have a significant impact on California’s olive industry. However, according to the 2017 report, there is no control program for OBB in the state of California, including no approved treatments or planned surveys and no plans for an interior quarantine. Since then, we do not know what the pest status of this beetle is in the United States.
Click here to read the initial report released by CDFA in 2017.
I reached out to CDFA and a few universities where olive is mainly growing in California (San Joaquin to Sacramento valleys, which have suitable climate similar to the Mediterranean region where olive is native). There are no concerns about OBB in California by the olive growers after OBB was discovered in 2016, CDFA said.
It is important to conduct surveys in the coming years, especially around the client's neighborhood area and proximity, to assess whether OBB may have become established in Ohio. We kept the figurine for nearly 5 months inside a sealed chamber. There were no further signs of live beetles or larvae.
References
Mifsud, David, Knizek, Milos. 2009. The Bark Beetles (Coleoptera: Scolytidae) of the Maltese Islands (Central Mediterranean). Entomological Society of Malta. Bulletin of the Entomological Society of Malta. 2009, Vol.2, p. 25-52
https://www.um.edu.mt/library/oar/handle/123456789/385
CDFA, 2017 - https://blogs.cdfa.ca.gov/Section3162/?p=3248
Olive trees in California: varieties to plant - https://www.gfloutdoors.com/olive-trees-in-california-varieties-to-plant/#:~:text=What%20Types%20of%20Olive%20Trees%20Can%20Grow%20in,Olive%20Trees%20...%205%20Leccino%20Olive%20Trees%20