Attempting to remove the spots from surfaces is generally futile. To remove these spots from buildings, try soaking the area with soap and water. Gentle scraping may be needed to loosen the peridioles, but care must be taken to avoid damage to the surface or the paint. Bleach water may also help to remove these spots, however, be sure to do a small test area first to avoid damage to the surface or the paint. Any person using products listed assumes full responsibility for their use in accordance with current direction of the manufacturer.
Information listed is valid only for the state of Indiana.
If you didn't see your plant or pest problem mentioned, send your question or comment to our panel of experts at the Plant and Pest Diagnostic Laboratory at Purdue University. We'll try and post as many questions and answers here as we can.