Our number one question that we get asked all the time is “What are those tiny black spots on our vinyl siding?” I’m here to tell you those tiny black spots are called “shotgun fungus” also known as Artillery Fungus. The scientific name is Sphaerobolus Stellatus.
This fungus gets it’s name because it expels from it’s fruiting bodies like a cannon. The mature spores can fire masses in the air up to several feet! This can reach second story vinyl siding – yikes! These tacky spores latch on to surfaces and are not only a nightmare but next to impossible to remove.
So where does this fungus come from exactly? The main culprit is infected mulch. Artillery fungus thrives in cooler, moist, and shady areas. If you notice artillery fungus on your siding, the infected mulch is not far away.
Unfortunately, Allbrite doesn’t have a recommendation for removal of the fungus. Pressure washing does not remove the spores. If a company tells you they can remove the spores RUN! That’s a fast track to damaged siding. The best solution is prevention. Especially if you have white vinyl siding. If you must have mulch by your siding, we do recommend to routinely check your mulch. If you start to notice black spots, remove the mulch immediately.