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Species Xyleborinus saxesenii - Fruit-tree Pinhole Borer

tiny black beetle with mites - Xyleborinus saxesenii Bark beetle from Virginia 10.06.26 - Xyleborinus saxesenii Xyleborus - Xyleborinus saxesenii Fruit-tree Pinhole Borer - Xyleborinus saxesenii Xyleborinus saxeseni - Xyleborinus saxesenii - female Ips? - Xyleborinus saxesenii Scolytinae - Xyleborinus saxesenii Xyleborus celsus? - Xyleborinus saxesenii
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Polyphaga (Water, Rove, Scarab, Long-horned, Leaf and Snout Beetles)
No Taxon (Series Cucujiformia)
Superfamily Curculionoidea (Snout and Bark Beetles)
Family Curculionidae (Snout and Bark Beetles)
Subfamily Scolytinae (Bark and Ambrosia Beetles)
Tribe Scolytini (Typical Bark Beetles)
Subtribe Xyleborina
Genus Xyleborinus
Species saxesenii (Fruit-tree Pinhole Borer)
Other Common Names
Common Eurasian Ambrosia Beetle, Asian Ambrosia Beetle; Lesser Shot Hole Borer(1)
Explanation of Names
Xyleborinus saxesenii (Ratzeburg 1837)

From (2): “Wood and Bright (1992) (3) and most authors list this species as X. saxeseni, but Holzschuh (1994)(4) points out that Ratzeburg's original description was saxesenii, with the ii ending.”
2.0-2.4 mm (2)
Native to, and widespread in, the Palaearctic(5), adventive in NA, with disjunct populations in the east (NS-FL to ON-KS-TX) and west (BC-CA)(6)(7)
Wide host range that includes ornamental trees, stone fruits and timber. Almost all conifers and hardwoods are susceptible. Economic damage to fruit trees has been particularly devastating.

This species feeds only in dying trees and generally trunks of large size. Oak, hickory, beech, and maple seem to be preferred. Much injury is done to timber because the flat chambers cannot be remedied by plugging.(8)
Life Cycle
The young are gathered in a brood chambler at the end of a gallery into heartwood. They are standing on edge, parallel with the grain with little only the thickness of the body as the space between the gallery walls. The entire wall surface of the gallery is plastered with ambrosia fungus. The brood chamber can be packed with eggs, larvae, pupae, and adults. The larvae extend the chamber, wood passing thru their bodies becoming mustard-yellow. Most of this is ejected from the colonies but a portion is retained to form a bed for new crops of food fungus.(8)
earliest record in our area: CA 1911(9)
Internet References
Fact sheet - Espinosa & Hodges (2009)
Works Cited
1.Handbook of urban insects and arachnids: A handbook of urban entomology
Robinson W.H. 2005. Cambridge University Press.
2.North American Xyleborini north of Mexico: a review and key to genera and species (Coleoptera, Curculionidae, Scolytinae)
Demian F. Gomez, Robert J. Rabaglia, Katherine E. O. Fairbanks, Jiri Hulcr. 2018. ZooKeys 768: 19-68.
3.A Catalog of the Scolytidae and Playpodidae, Part 2 Taxonomic Index
Stephen L. Wood. 1992. Great Basin Naturalist Memoirs, No. 13.
4.Zur unterscheidung von Xyleborinus saxesenii (Ratzeburg) und X. alni (Niisima) (Coleoptera, Scolytidae)
Carolus Holzschuh. 1994. Entomologica Basiliensia.
5.Coleoptera Poloniae
6.Atkinson T.H. (200_-2018) Bark and ambrosia beetles
7.Checklist of beetles (Coleoptera) of Canada and Alaska. Second edition
Bousquet Y., Bouchard P., Davies A.E., Sikes D.S. 2013. ZooKeys 360: 1–402.
8.Rhynchophora or weevils of North Eastern America
Blatchley and Leng. 1916. Nature Publishing Co., Indianapolis, Indiana. 682 pp.
9.Exotic bark and ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) in the United States: potential and current invaders
Haack R.A., Rabaglia R.J. 2013. In: Potential invasive pests of agricultural crops. Peña J.E., ed. CABI International, Wallingford, UK, pp. 48-74.