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ArborCare ArborScape (801) 972-Tree (8733)

Oak Anthracnose

What is oak anthracnose?

Oak Anthracnose is a fungus called Apiognomonia quercina that attacks a variety of oak species. Like other fungi, this normally infects in the trees during cool, wet springs, especially when the moisture is prolonged.

How do I know if my oaks have anthracnose?

The signs begin with blotches on the young leaves. These typically appear along the midrib and main veins of the leaf. These turn to larger, tan to brown spots with some leaf shriveling possible. As the leaves mature, they tend to be more resistant and the infection spreads less, although there may be premature leaf drop if the infection is bad. The fungus itself can sometimes be seen as tiny black spots on the undersides of the leaves.

Oak Anthracnose normally does not affect the twigs as much. The infections tend to serve just as overwintering sites. There can be, however, some twig dieback if the infection is bad enough.

What can I do to control oak anthracnose?

One of the most important methods of control is to keep the leaves raked. Be sure to destroy the leaves, not compost them, to help prevent the spread of fungus. Also, the diseased branches should be pruned and destroyed.

Another important step to take is to avoid overhead watering. Excess water on the leaves can attract the fungus. Be sure to direct your sprinkler heads in a manner to avoid the leaves as much as possible. Also, watering in the morning instead of the evening gives the leaves a better chance to dry, which can help slow Oak Anthracnose as well.

Fungicide treatments are available and can help reduce the amount of disease. These should be done in the spring at bud break. Two to three applications are necessary for the best control, depending on how damp the spring is. Once the weather begins to dry, fungicides are no longer necessary.

We always suggest keeping the trees healthy. Regular fertilizing will give the trees the nutrients they need to defend themselves from insects and diseases like Oak Anthracnose.

What can Arbocare do for me?

We offer spring fungicide treatments to help reduce the infection. We do suggest three applications for Oak Anthracnose for the best control. The fungicide is applied two to three weeks apart. We also offer fall or spring fertilization. We use an organic, slow-release fertilizer to supply the trees with the nutrients they need. ArborCare provides a variety of treatments to take care of your tree and shrub care needs. Call (801)-972-8733 with any quesitons you may have!

If you have any questions or would like to speak with an ArborCare representative regarding your tree care needs, please e-mail us at or call us at (801) 972-8733.


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