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Cedar-apple rust

Gymnosporangium juniperi-virginianae


On the Eastern Red Cedar host, the fungus produces reddish-brown galls from 1/4 to 1 inch in diameter. These galls can be mistaken for cone structures by the uninitiated. After reaching a diameter of about 1/2 inch, they show many small circular depressions. In the center of each depression is a small, pimple-like structure. In the spring these structures elongate into orange gelatinous protrusions or horns. The spore-bearing horns swell during rainy periods in April and May. The wind carries the microscopic spores to infect apple leaves, fruit and young twigs on trees within a radius of several miles of the infected tree.


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Maria dB
Maria dB 8 years ago

Thanks, Luis. I had always thought it was part of the tree until I started looking into it more. I have an apple tree in my yard, too, and this may be why the apples stay very small - but the birds and deer still like them.

LuisStevens 8 years ago

I saw some just like this in a hiking trip but too tired to take a picture, I'm glad you did and now I know what they are.

Maria dB
Spotted by
Maria dB

Chapel Hill, North Carolina, USA

Spotted on Apr 7, 2013
Submitted on Apr 16, 2013

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