Is White Fungus on Trees Dangerous?

Is white fungus on trees dangerous? The short answer is that it depends on whether it’s due to powdery mildew disease or heart rot. In this article, S.M.B. Family Tree Service, House Springs’ tree service experts, explains when you should worry about this unsettling sight. 

Heart Rot

Heart rot means that the infected tree is dying from the inside out. By the time you see signs of infection, the situation is serious. This is one of the worst fungal diseases because it slips under the radar. 

By the time you see the white, mushroom-like growth, getting the tree healthy again is challenging. For each of these outcroppings, you lose about a cubic foot of wood to rot. The more of these there are, the higher the chance that fungus compromised the entire tree.

Treating Heart Rot

The best treatment is to call an arborist. They will do everything they can to save the tree, but they also know when they can’t. If the disease is too far gone, they’ll advise removal and that you burn the stump to prevent the infection from spreading. 

They’ll also suggest a proactive strategy to prevent a recurrence. What’s most important here is to protect your trees from wounds they sustain, as this is how the fungus gains entry. They may also recommend a series of annual evaluations so that you can stamp out future infections early.

Powdery Mildew

Powdery mildew looks ugly and spreads fast, but it is not nearly as deadly as heart rot. So the answer to, “Is white fungus on trees dangerous?” is, “No.” here.  It is common, especially in moist conditions. You will often find this disease affecting Dogwoods, Maples, Basswood, and Magnolias.

This type of mildew can have many symptoms, especially across different species. It’s also generally worse in younger plants. 

It may look like a layer of fine white dust that seems easy to wipe off on the trunk and leaves. It may look like spots of pure white color that stand out. Over time, the tree’s leaves will discolor and drop off due to a lack of nutrients. 

In some cases, the tree will grow what looks like white mushrooms, much as is the case with heart rot. These may develop into spherical fungal masses in late summer or the early fall. 

Treating Powdery Mildew

This fungal disease spreads quickly but rarely kills the tree. It can, however, cause nasty scars and set back growth for a time. There are several fungicides on the market that will do the job. Just be careful and check for toxicity towards your other plants. 

Would you prefer a more natural option? Mixing baking soda and water and spraying it on can be an effective way to kill the mildew, as can dousing the spots with neem oil.

Proactive maintenance goes a long way to preventing this disease. The fungus thrives in moist, humid conditions, so planting trees in bright sunlight and ensuring good airflow are key strategies. Spacing your trees properly will also help, as will trimming dead wood regularly. 

Aside from that, use good common sense. Don’t compost infected leaves or other parts; rather, burn them or leave them for refuse removal.

Contact Us for Advice

Do you suspect a tree trunk rotting from the inside? Without cutting into it, it’s difficult to tell for certain, and this inspection comes with dangers of its own. Now that you know that the answer to, “Is white fungus on trees dangerous?” why not let a pro from S.M.B. Family Tree Service take a look and give you advice? 

Dial (636) 212-1852 for a consultation. 

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