cedar apple rust / cedar hawthorne rust

these weird brain-looking things are cedar apple rust (or maybe cedar hawthorn rust).


they grow on the dwarf cedar tree in my backyard.


pulling them off means parts of the branches comes off too.


there was just a freaking TON of these things this spring


the rash i get from touching juniper or cedar or arborvitae. or pretty much any evergreen.


if i'd left them on thru spring they'd eventually start growing and look like this


the orange horns grow longer and longer and longer and are the spores of the fungus which affects both cedar and apple trees. if its cedar hawthorn rust, which looks kinda the same, it can affect pear trees. i dont want my pear trees infected.

cedar apple rust

This is a gall, caused by the fungus Gymnosporangium juniperi-virginianae. Galls appear when an insect or fungus feeds off of a plant and somehow changes the plant's structure, causing it to produce abnormal growths, inside of which the insect or fungus then lives. Those "tentacles" are actually the spore-producing appendages of the fungus inside the gall.









It can defoliate trees and blemish fruit making them unmarketable. The CAR fungus requires two hosts, apple and eastern red cedar. it makes spots on the leaves of apple trees AND pear trees very much like the spots i've been having trouble with on the summercrisp and patten trees.

treatment seems to be sulfer. but is supposed to be applied when the blossoms are open and that has passed.