There are over 100 species of the genus Pinus world wide, of which 36 are native to the United States. Pines grow best in full sun on well-drained, acid soil. Symptoms consist of purplish spots at the site of stem infection.
Stems begin to swell four to six months after infection, resulting in spindle-shaped galls.
Dieback of small stems or cankers on larger stems often occur. Galls slowly enlarge each year. During the spring blister-like fruiting bodies break through the pine bark releasing yellow spores, which are spread by wind and infect the leaves of oaks, the alternate host. Orange specks develop on the underside of the oak leaves. In early spring spores are spread back to pines by wind.