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Planting apple trees near cedar

Apple   

I have been told by a friend (who also happens to live next door) that I should not plant apple trees in the yard as there are cedars growing in the area and they can get a disease from them. There is a small patch of cedars growing about 3 miles away as far as I know - are they really going to be a threat?


Posted by: Alex Ramirez (2 points) Alex Ramirez
Posted: March 8, 2013




Answers

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Your friend is referring to a disease called cedar apple rust, a fungal pathogen which can cause serious damage to apple trees.

Cedar apple rust is caused by a fungus called Gymnosporangium juniperi-virginianae. It has a very complex life cycle which requires two hosts to complete. One of these hosts is apple, the other is Eastern red cedar. The disease is spread to apple after the fungus has spent approximately 18 months on the cedar tree. Small, green to brown galls are produced on the cedar 1 year after infection and they mature by year 2, releasing spores after warm spring rains. The spores are transferred to the foliage and/or fruit of apple trees by the action of the wind and can quite easily travel 2-3 miles in this manner. After infection, yellow spots of rust will begin to appear on the leaves of the apple tree, usually within 1-3 weeks, depending on environmental conditions. The pathogen will also infect apple fruit and in the summer, the reproductive bodies of the fungus will release more spores to transfer the pathogen back to cedar and complete the life cycle. The total cycle takes about 2 years to complete.

If you want to plant apple in your garden and have cedar in such close proximity, I would advise you to exercise caution. There are some apple varieties that possess resistance or tolerance to cedar apple rust and I would recommend that you look into these. Varieties such as Dayton and Delicious are highly resistant to the pathogen and may be a good bet for you depending on your location. Good luck!




Posted by: Lindsay McMenemy (2 points) Lindsay McMenemy
Posted: March 8, 2013




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Don't let the presence of cedars three miles away prevent you from planting an apple tree. The rust spores can travel that far, yes, but such a distance would cause a good percentage of spores to fall out along the way, essentially dilution by distance. I would be more concerned about cedar trees growing within 1/4 mile. This is a one-time per year disease, in other words, the spores go one way, from cedar-to-apple or from apple-to-cedar, not from apple-to-apple. Any infection on apple does not continue to multiply and reinfect other leaves on the apple tree. And there are a number of apple varieties that have very good rust resistance.

I copied the following text on resistant varieties from an Iowa State University extension website at http://www.ipm.iastate.edu/ipm/hortne....
An easy way to avoid this disease is to plant disease resistant apple or crabapple varieties. Fortunately, there are many varieties available now that show good disease resistance. Redfree, Liberty, William's Pride, and Freedom are examples of new apple varieties that are immune to cedar-apple rust. These varieties are also immune to apple scab and show good resistance to powdery mildew and fire blight. Examples of apples that are susceptible to cedar-apple rust include Jonathan, Rome, Wealthy, York Imperial, and Golden Delicious.


Posted by: Charlie B. (84 points) Charlie B.
Posted: March 19, 2013




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