Start Date
23-4-2026 12:00 AM
Description
Horned oak galls are woody growths found on the branches of oak trees (Quercus sp.). These growths are caused by the parasitic wasp, Callirhytis cornigera. These wasps produce the galls by piercing the branch with their ovipositors and laying eggs into the branch. Based on the severity of infestation, these galls can cause severe damage or even death to oak trees. This research determined the dispersal and severity of horned oak galls infesting the different species of oak trees around the heritage side of Lindenwood. This was done by walking around the heritage side of campus and observing different species of oak trees to determine if they contained tree galls and the severity of galls. Then, using an existing map of oak trees on the heritage side on ArcGIS, each tree was documented to determine the presence, or absence, and severity of infestation on each tree.
Research Highlights
The Problem: Horned oak galls, woody growths caused by the parasitic wasp Callirhytis cornigera, create trauma to tree branches and pose an infestation risk to oak species.
The Method: Researchers surveyed 27 oak trees (Quercus sp.) on the heritage side of the Lindenwood University campus using ArcGIS mapping to document the presence, absence, and severity of infestations based on a scale ranging from minor (25% or less) to severe (80% or more).
Quantitative Finding: 10 out of 27 surveyed trees contained galls; 50% of the infested trees were Pin Oaks (Q. palustris); the remaining 50% of infested trees consisted of White Oaks, Northern Red Oaks, and Bur Oaks; the wasp life cycle involves eggs held within galls for 33 months.
Qualitative Finding: C. cornigera wasps demonstrate a preference for Pin Oaks due to specific chemical emissions from the tree; despite close proximity between trees, infestation does not universally spread to all neighboring oak specimens.
Recommended Citation
Birkenmeier, Peyton and Sesterhenn, Timothy, "Horned Oak Galls and Their Dispersal on Lindenwood's Campus" (2026). 2026 Student Academic Showcase. 21.
https://digitalcommons.lindenwood.edu/src_2026/Posters/1/21
Included in
Horned Oak Galls and Their Dispersal on Lindenwood's Campus
Horned oak galls are woody growths found on the branches of oak trees (Quercus sp.). These growths are caused by the parasitic wasp, Callirhytis cornigera. These wasps produce the galls by piercing the branch with their ovipositors and laying eggs into the branch. Based on the severity of infestation, these galls can cause severe damage or even death to oak trees. This research determined the dispersal and severity of horned oak galls infesting the different species of oak trees around the heritage side of Lindenwood. This was done by walking around the heritage side of campus and observing different species of oak trees to determine if they contained tree galls and the severity of galls. Then, using an existing map of oak trees on the heritage side on ArcGIS, each tree was documented to determine the presence, or absence, and severity of infestation on each tree.