Alert: Root Rots Damaging Trees

Root rots damage trees and shrubs by attacking and killing smaller roots and then progressing to larger and larger roots as favorable conditions persist. The alternating wet and drought periods experienced over the last few years were especially conducive to root rot attack which can weaken roots, reduce tree stability and eventually lead to tree loss if left untreated. Root rot disease can be caused by various fungi, such as Armillaria, Ganoderma, Inonotus, Laetiporus, and Annosum species. It can also be caused by a unique group of organisms called water molds. Phytophthora and Pythium are in this class.

• Symptoms include poor growth, loss of healthy needle or leaf color, dark brown or black discolored wood at the base of the stem or trunk for several inches above and/or below the soil line (sometimes higher), and loosening /separation of the dead lower bark from the trunk
• Other symptoms include slowed growth, smaller than normal needles or leaves, excessive cone or seed set, premature autumn color, and winter twig dieback (can be severe). As a result of the fungal infection, the root system is reduced and has dark brown or black areas.

Roots are more susceptible if damaged physically from trenching, digging, etc., or if the root system is in a low area where water collects. Changes in grade can make water collect in previously normal areas, which can encourage infection. Heavy, clay soils tend to favor root rot more due to their water absorption and retention properties.

This type of damage has been increasing steadily this year and needs intervention when encountered. Once a root system is infected, the spores will always be present and the condition cannot be eradicated, but treatment measures can be quite successful in achieving and sustaining remission. Because many different organisms can be the cause, a determination must be made to formulate an effective treatment strategy.

Your Wachtel Tree Science Certified Arborist is qualified to make such a diagnosis. Call for an evaluation when root rotis suspected. This is not a rare condition, and most trees can be saved with timely treatment!

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