Comandra Blister Rust

<em>Cronartium comandrae</em>, known as comandra blister rust, is a parasitic fungal pathogen in the family Cronartiaceae that alternates between two unrelated host plants to complete its life cycle. The fungus infects coniferous trees, particularly pine species, during one phase of its development, causing characteristic blister-like galls on branches and stems that can girdle and kill infected tissues. The alternate host is typically comandra (<em>Comandra umbellata</em>), a parasitic flowering plant. On pine hosts, the rust forms orange or yellow spore masses during the aecial stage, releasing spores that infect comandra plants, where urediniospores and teliospores are subsequently produced. The species is distributed wherever its dual hosts co-occur across North America and parts of Eurasia. It can cause economically significant damage to pine plantations and natural forest stands. No quantitative biological metrics are recorded for this species.