Gymnosporangium juniperi-virginianae is a plant pathogen that causes cedar-apple rust. In virtually any location where apples or crabapples Malus and Eastern red-cedar Juniperus virginiana coexist, cedar apple rust can be a destructive or disfiguring disease on both the apples and cedars. On juniper or eastern red cedar, small 3/8 to 1 and 3/16 inches in diameter galls develop throughout the tree on needles and small twigs. When mature, these galls swell considerably and repeatedly produce orange, gelatinous telial horns during rainy spring weather. As spring rains subside, the galls die, which may cause death of the twig from the gall to the tip.
|
