If your siding, car, fence or any other surfaces around your house have broken out with a rash of black or dark-brown specks that do not want to come off, you are probably at war with something called Artillery fungus.
I have seen this on many homes over the years, but I have noticed a drastic increase in the number of homes that have been "shot"! The following picture is from a home that I just inspected, even the PVC plastic privacy fence had been shot!
The artillery fungus, cannon fungus or shotgun fungus resembles a tiny cream or orange-brown cup with one black egg. The cup is approximately 1/10 of an inch in diameter. Areas of mulch with artillery fungi may appear matted and lighter in color than the surrounding mulch. The fruiting body of this fungus orients itself towards bright surfaces, such as light-colored houses or parked automobiles. The artillery fungus "shoots" its black, sticky spore mass which can be windblown as high as the second story of a house.
After doing some research I think that I have discovered why we are seeing more homes with artillery fungus problems. It looks like the appearance of Artillery fungi has been associated with wood mulch (versus bark mulch) and the increased use of wood products in potting media. Mostly the use of ground-up wood pallets and unused pulp wood and the use of fallen trees from storms that have been ground into mulch .
The best way to limit your exposure is the composting of these products prior to incorporation into media is encouraged to prompt the growth of beneficial antagonistic organisms. Better yet, use only the bagged or prepackaged mulch from a garden center. Bulk mulch (not in bags) tends to be more of a raw material that could contain spores.
Also, the use of gravel mulch, stone, pea gravel, and black plastic next to buildings instead of using wood products will help reduce the problem. If wood products are used, the addition of about 3 cm of fresh mulch to cover old mulch each year may lessen the problem. Use of bark products, rather than wood products, may also lessen the fungal spread.
One word of warning to homeowners wishing to replace house siding splattered by Artillery fungi --- insurance companies may not cover claims of damage due to "molds".
Scott Patterson has been a professional home inspector since 1995 and works out of the Greater Nashville TN area. You can contact him at his office 615-302-1113 or on his cell at 615-870-4162 via text or voice.