If you notice fungus on the trunk of your apple tree, it's important to treat it as soon as possible. Fungus can weaken the tree and make it more susceptible to disease and pests. There are a few different ways to treat fungus on an apple tree trunk.
One way is to apply a fungicide. There are many different fungicides available, so be sure to read the label carefully and choose one that is specifically designed for treating fungus on trees. Apply the fungicide according to the instructions on the label.
Another way to treat fungus is to create a mixture of one part bleach and ten parts water. Use a clean cloth or brush to apply the mixture to the affected areas of the trunk. Let it sit for about 30 minutes before washing it off with clean water. This method should only be used as a last resort, as bleach can damage the bark of the tree if not used correctly.
If you have persistent problems with fungus on your apple tree trunk, you may need to consult with a professional arborist or tree care specialist. They will be able to diagnose the problem and advise you on the best course of treatment.