Influence of Mulch Characteristics on Sporulation by the Artillery Fungus Sphaerobolus stellatus

Abstract The artillery fungus (Sphaerobolus stellatus) is a common, white-rotting wood decay fungus that grows on landscape mulch. During colonization, the fungus produces dark-brown, sticky spore masses (gleba) that it shoots from the mulch towards a source of light or light-colored objects. The gleba adhere tightly to surfaces such as the sides of houses or cars. Twenty-five landscape mulches were evaluated in the field and laboratory to determine which mulches supported or inhibited the artillery fungus. Although the artillery fungus eventually grew on most types of mulch, some mulches supported more sporulation than others. The artillery fungus did not grow or sporulate well on mulches made from large pine bark nuggets, Atlantic white-cedar, or cypress. We recommend these mulches for use in areas having an existing or potential artillery fungus problem. However, even these mulches should be replaced with new mulch on a regular basis.