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A Guide to Annosus Root Rot

31 MAY 2023

A Guide to Annosus Root Rot

Trees are more than just healthy branches and thick foliage—they have a vast root system growing beneath the ground. While most tree infections are easily noticed, it can be challenging for homeowners to detect root damage. Hence, hiring a professional tree care company for regular maintenance goes a long way in detecting minor signs of deterioration before things get out of hand. If your trees have Annosus root rot, delaying treatment can cause growth loss, root decay, and death. At the Sesmas Tree Service, we ensure your trees are healthy yearlong by inspecting and addressing telltale signs of infection.


Annosus root rot causes more damage in pine and fir trees, but confers and white fir are also susceptible to the fungus. As mentioned, roots grow below the ground, making detection nearly impossible for inexperienced individuals. Only a certified tree service provider can diagnose the disease, even in pines, true firs, and hemlock, where the damage is more pronounced. Although the initial stage of Annosus root rot infection doesn’t raise concerns, it is critical to address the problem immediately. Many emergency calls we get result from not detecting signs early, and that’s why we recommend hiring an expert.


If you suspect a problem with your trees, you must schedule a consultation with a professional tree care company. The most noticeable signs of Annosus root rot include reduced growth, needle yellowing, health decline, and death. These symptoms often appear in resinous hosts like pines and should be addressed immediately. For non-resinous hosts, symptoms of infection include a white string rot or stain in the roots. Rot may exhibit black specks.

Dead trees or stumps caused by Annosus root rot may have bracket-shaped leathery conks in crotches, hollows, or the root collar. Professional tree service providers can handle the removal of dead trees and stumps, preventing the spread of the disease to healthy trees.

Disease Spread

Annosus root rot is a fungal disease spread via spores from infected trees or stumps. Windborne spores infect healthy trees through wounds, and the cycle continues across root grafts and contacts. After the first treatment, follow-up inspections by a certified tree care company to mitigate a secondary attack by bark beetles. This is usually the case following a fungal infection and can wreak havoc in your yard.


Prevention is the best cure, and in Annosus root rot, it is no exception. We urge property owners to practice safe logging and the removal of severely wounded trees. This also goes a long way to minimize decay, allowing us to salvage the tree and prevent further spreading. Tree decay associated with root rot or wounds is a common problem that affects many homeowners across the country, and that’s why we dedicate our expertise to helping stop the scourge. 

Please don’t ignore telltale signs of Annosus root rot; contact us at the Sesmas Tree Service and schedule an appointment with our certified arborists. We provide a wide range of services guaranteed to enhance the health and lifespan of your trees.