Cedar-hawthorn rust occurs on cedar, juniper, apple and crab apple, hawthorns etc. In order to survive, the fungus generally moves from one type of host to another (for instance, from juniper to hawthorn).
Small yellow spots first appear after infection in the spring. As the spots mature and enlarge, they take on an orange color and develop tiny black dots in the center of the lesion. By mid-summer, tubes are visible on the undersides of mature leaf lesions or within the lesions on fruit, petioles or twigs infections. With severe rust, hawthorn foliage may turn bright yellow and drop prematurely.