Found these on some cedar trees in my back field, was wondering if you knew what these were?
[submitted by @lady8ces]
Yes! This is a Gymnosporangium species; I think they’re older clusters of Gymnosporangium juniperi-virginianae - known as cedar apple rust.
Really interestingly, it relies on two trees to live and spread.
Spores infect apple and crabapple trees, causing the rust red spots from which it gets its common name. Once mature, these bodies release spores which will infect juniper and cedar trees. The spores from an apple tree cannot infect another apple tree, and those from a coniferous tree cannot infect another coniferous tree; each year reproductive bodies of this fungus will release spores and move between the two hosts. It therefore thrives in areas where these two kinds of tree coexist. You can read more about this intricate lifecycle here.
This pathogen doesn’t usually kill its host trees as it lives and feeds on the living flesh, but a large or repeated infection will weaken it and will damage fruit production; it also tends to be avoided because of the detriment to the ornamental value of trees, causing rust red spots on the leaves of apple trees, and these large clusters and quite lackluster looking pines on the coniferous trees it affects.
It's clearly some Invasion of the Body Snatchers kinda shit. Don't fall asleep nearby!













