Artillery fungi (Sphaerobolus spp.) have recently emerged from an interesting mycological curiosity that grow in landscape mulch, to a problem of emotional stress and financial concern to homeowners, as well as insurance companies, mulch producers, and landscape contractors. Artillery fungi shoot their spore masses (gleba) towards sunlight and/or reflective objects such as light-colored house siding or automobiles, peppering the surface with small sticky tar-like black specks. Once dry, gleba are very difficult to remove from surfaces such as vinyl siding. If they can be removed, gleba usually leave a brown stain that is extremely difficult to clean. We previously reported that aged (weathered or composted outside) mushroom compost (MC), when blended with landscape mulch at ≥ 40% by volume, suppressed artillery fungi sporulation in the mulch. In this paper, we report that fresh MC, taken directly from the mushroom house and blended with landscape mulch without aging, also reduces artillery fungi sporulation as follows: 0% MC (control = 0% reduction), 10% MC (62%), 20% MC (80%), 40% MC (95%), and 100% MC (97% reduction in sporulation). Landscape companies using fresh MC, rather than aged MC, need not invest time and money in additional MC aging, composting, and processing.

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Author notes

The main funding for this study was provided by Giorgi Mushroom Company, Temple, PA. The authors also acknowledge financial support from The Pennsylvania Department of Agriculture, Harrisburg, and the American Mushroom Institute, Washington, DC.

2Professor, Department of Plant Pathology, The Pennsylvania State University, University Park, PA 16802. ddd2@psu.edu.

3Associate Professor, Division of Science, The Pennsylvania State University, Reading, PA 19610. maf100@psu.edu.