Artillery Fungus and the Shotgun Effect

Gary Smith - Today's Home Inspector - SafeHome InspectionsManaging editor and real estate industry writer :: Gary Smith

You can’t get this stuff off your car or house! That’s what some folks will tell you about Artillery Fungus.

Many people are concerned by the tiny dark spots they find on their houses, cars, and plants. Often the spots are mistaken for scales. The spots may actually be spores from members of a group of fungi commonly called the “shotgun” or “artillery” fungi in the genus Sphaerobolus. These fungi colonize dung or other organic matter such as wood mulch, wood benches, wood sheds, etc. source:

Tindy dots on siding

Tiny dots of Artillery Fungus on siding at recent home inspection – Image Source:

Home inspectors are likely to see this in the cool, wet days of the spring and autumn because the fruiting body is not produced above 77°F.

Control strategies consist mainly of altering the habitat so the fungus does not grow. Where mulch is suspected as the fungus source, it should be removed and new mulch put down in its place. Alternatively a new layer of mulch may be placed on top of the old to act as a barrier. Large-nugget bark mulches of pine, Atlantic white cedar, or cypress are more suppressive to Sphaerobolus than most organic mulches, but inorganic mulches would not support any growth of the fungus and would be a more permanent solution

HOW TO WRITE UP: Today’s Home Inspector member Robert Kulakowski says,

Robert Kulakowski

Robert Kulakowski

…it is considered a cosmetic issue IMHO. If I write it up I make it informational – Possible artillery fungus stains were observed on the siding in the [front] side of the home. This condition is many time the result of wood bark mulch. Contact a competent landscape contractor for further advice.

The stains generally can’t be cleaned. Its more of a problem for vinyl siding, most others can be painted.

  1. Here is a solution we recommend for removing the black spots:
    • 1/2 cup detergent (Tide, for example)
    • 2/3 cup trisodium phosphate (Soilax, for example)
    • 1 quart 5% sodium hypochlorite (Chlorox, for example)
    • 3 quarts water

    We suggest applying this solution with a soft bristled brush and removing with water.

Learn more tips and tricks  from home and car owners.


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