Pest Alert United States
Department of

Forest Service

Northeastern Area
Region 8


Hickory Mortality

Photo 1 Photo 2
Photo 1: Varying stages of mortality in bitternut hickory. Declining (yellow leaves), recently dead (brown leaves), and trees dead for an extended time (no leaves). Photo 2: Egg and larval galleries of the hickory bark beetle found under the bark of infested hickories. The dark discoloration is the Ceratocystis sp. fungus.
Mortality of bitternut and shagbark hickory has been observed in Wisconsin since the late 1980's. This is similar to occurrences in the 1960's. The recent tree mortality has been associated with affacks by the hickory bark beetle, Scolytus quadrispinosus Say, and a newly discovered fungus in the genus Ceratocystis (tentatively C. caryae). The fungus can be isolated from sunken bark cankers and discolored wood associated with beetle attacks. In field and greenhouse studies done at the University of Wisconsin, the fungus was found to be highly virulent to bitternut and shagbark hickory, pecan, butternut and black walnut.

Recent reports indicate hickory mortality is apparently widespread across the eastern United States. It has not been determined if this mortality is always associated with the hickory bark beetle or with the Ceratocystis sp. fungus. You can help us delineate the extent of the problem by reporting any hickory mortality.

Photo 3 Photo 3: Fungal development deep into the wood on a cross-section of shagbark hickory about one year after bark beetle attack.

Photo Credits: Dr. Eugene Smalley
Department of Plant Pathology
University of Wisconsin-Madison
Madison, WI 53706

USDA Forest Serviced Shield
Please send reports of dying hickory to:

Manfred Mielke and
Steve Katovich
Forest Health Protection
St. Paul, MN