Friday, March 23, 2012

Gymnosporangium Juniperi-Virginianae

Always on the lookout for something interesting and new to take pictures of, I discovered this substance on a few cedar trees last year.  I have been waiting for it's appearance this spring, and I wasn't disappointed after the rains we have had the past week.

Randy and I call it cedar jelly.  And no, we don't spread it on our toast.  The layman's name for this is Cedar Apple Rust Fungus.  Basically it is a rust colored blob of goo found on some unfortunate cedar trees on our property.  Randy and I both noticed the blobs early last spring after a day or two of storms.

Well, I am sure that our cedar trees aren't special in being the only trees attacked by the fungus, I just have never taken the opportunity to inspect the neighbor's trees.

Cedar Apple Rust (or Gymnosporangium Juniperi-Virginianae) is a two-stage disease.  Cedar trees are actually the host of the fungus.  Growths form on the branches of the cedar trees.  These growths are covered with dimples and at the center of each dimple is a blemish.

I was going to say 'pimple' instead of blemish, but 1) I didn't want to rhyme and, B) I don't really care for the word 'pimple'.

Anyway ~ 

During the spring rains, these blemishes swell to become gelatinous balls of goo with 'horns'.  Teeny tiny spores from these horns are carried by the wind to apple trees.  Apple trees within a several mile radius of the infected cedar trees are at risk.  The spores make it to the apple trees right around the time they start to blossom.  The spores attach themselves to the leaves, germinate and infect the leaf or the fruit itself.  The infected apple is small, deformed and unattractive.  If left untreated, the fungus would eventually kill the apple tree.

In the summer, the fungi produces spores from the apple leaves.  The spores are then blown back to the cedar trees (that pesky wind!) and the cycle starts all over again.  The tiny spores land in cracks and crevices in the tree, germinate and make a small swelling on the tree.  The swellings grow and by the second year on a cedar tree the growths are able to produce the spores that infect the apple trees.

Treating the apple trees has been the preferred method of control.  The first line of defense, removing all the cedar trees within a mile radius of the apple tree, is not often practical.  Spraying a food-safe fungicide on the apple trees is more effective.  That same fungicide is also sprayed on the cedar trees during their infectious stage - when they are a gooey blobs - helping in reducing the outbreak.

Different types of apples are more susceptible than others - Rome Beauty and Jonathan's are more likely to get the fungus than Red Delicious or Winesap apples.  It is the same with crabapples.  While crabapples are more likely to get the fungus than apples, certain varieties of crabapples are more prone to get it than other varieties.

Cedar Apple Rust was identified by Danish botanist Anders Sandoe Oersted.  A wearer of many hats, Mr. Oersted was also a mycologist (the study of fungi), a zoologist and a marine biologist. He also named hundreds of plant species.  Wouldn't that be something?  To be the one to name a plant?

Now, the big question in my mind ... since it takes two to tango, so to speak, where in the world are the apple trees?

Have the BEST day ever!
~ Dorothy

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