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We have lost 2 pine trees and are now loosing our quaking aspen. It has black spots on leaves and trunk has back on it also. The leaves are falling off. Is there anything that can save the tree?

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Black spots on your Quaking aspen could be a fungal disease called aspen leaf spot.  The symptoms of this disease start out with small dark brown spots with light centers.  These spots will spread and eventually grow together and in severe cases the leaves may die and fall off. Most aspens will survive this disease but it can weaken them, making them susceptible to other problems. 

Below are two links.  One that has some pictures of what aspen leaf spot symptoms look like and one with more information on the disease. 

http://utahpests.usu.edu/plantdiseases/htm/ornamental/aspenspot/aspenspotimages

http://utahpests.usu.edu/plantdiseases/htm/ornamental/aspenspot


Control of this disease isn't easy but there are some things that you can do to help your tree out. Make sure to pick up and discard any fallen leaves.  This will help reduce the spread of the fungus.  Also, when working around the tree make sure that the lawnmower and weed eater do not run into it and damage the trunk. And when watering the tree try to avoid getting water on the leaves.  Below is a link with more information on watering trees.

http://extension.usu.edu/files/publications/publication/HG-523.pdf


You can also apply a protective fungicide spray at bud break and to the newly emerging foliage next spring. If you choose to use a fungicide make sure that aspen trees are specifically mentioned on the label.  There are some recommendations on products that can be used included in the second link above. 


If this does not look like the problem your tree is having bring a sample into our office.  We will help to identify the problem.  Our address is 2001 S. State Street #S1200.
 

Posted on 15 Jul 2009

Heidi Wayman
Horticulture Intern, Salt Lake County

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