On a juniper tree, brown, perennial galls appear on the branches. When mature, it continues to produce orange gelatinous horns in spring, when the weather is likely to be rainy. Sometimes the branch beyond the gall dies, but otherwise the host juniper does not suffer any further damage.
On an apple or crabapple tree, it appears as circular yellow lesions on the leaves shortly after flowering. In late summer, brownish clusters of threads or cylindrical tubes appear under spots on leaves, twigs or fruit.
Regarding the duration of the disease, the galls appear seven months after the start of the infection. They begin to transform into gelatinous masses after 18 months. Golf ball-like depressions then appear on the gall and give way to teleutosporian horns the following spring. In the spring rain, the brownish teleutosporian horns elongate and turn bright orange. After releasing their spores, the horns droop, dry out and fall off. Although the galls then die, they remain attached to the tree for at least a year. Infection is much more obvious in spring when the gall is covered with gelatinous masses.
