Black Spots on Ohio Siding: Likely Artillery Fungus or Insect Frass—Need Photo

Small (1/16"), hard-to-remove black spots on white siding in north-central Ohio are commonly:

• Artillery fungus (Sphaerobolus) — shoots sticky black spores from mulch onto siding. Spores are tar-like, very difficult to remove.
• Insect frass (droppings) — from overwintering bugs (boxelder bugs, stink bugs) or spider egg sacs.
• Mold/mildew spores — but usually softer, cleanable.

To Identify

1. Post a clear, close-up photo of the spots (with a coin for scale).
2. Describe the last sentence of your question—it was cut off ("They are usually on?").
3. Check the mulch. If you have wood mulch near the house, artillery fungus is highly likely.

If Artillery Fungus

• Remove and replace mulch near the foundation with stone or rubber mulch.
• Spots on siding may require pressure washing + scrubbing; some staining persists.
• No health risk; purely cosmetic.

I grew up in Parma—artillery fungus is common there with shredded hardwood mulch. A photo will confirm.