The Daily Croissant

"Cedar apple rust? A strange name for a fungus which affects the juniper, you might think. Yet cedar apple rust is so named because it is a disease which requires two hosts to complete its life cycle. To begin with it will spend the winter as a purple colored gall which looks a little like a brain on the branches of Juniperus virginiana....Although the glutinous orange mass looks deadly it does not kill either the juniper or its secondary hosts. However, it will infect apples and will also defoliate the trees so whenever farmers discover it, they will naturally attempt to eradicate it."