Cronartium quercuum, also known as pine-oak gall rust is a fungal disease of pine (Pinus spp.)

[1] Galls start to form as slight, rounded swelling on the tree stem, then grow to become spherical and elongate.

[2] Cronartium quercuum is found throughout North, Central, and South America, the Caribbean, and Asia.

C. quercuum is typically found in the eastern United States, spreading as far west as the Great Lakes region.

[2] Pycnia and aecia are produced on pine host in the spring and early summer one to several years after infection.

Uredinia form on the oak species 1–3 weeks after infection, telia develop about 15 days later.

Prune out galls to reduce spreading of spores to nearby pine or oak trees.