Cheatgrass and its cousin, red brome, are exotic annual grasses that have invaded and altered ecosystem dynamics in more than 41 million acres of desert shrublands between the Rockies and the Cascade-Sierra chain. A fungus naturally associated with these Bromus species has been found lethal to the plants’ soil-banked dormant seeds. Supported by the Joint Fire Science Program (JFSP), researchers Susan Meyer, Phil Allen, and Julie Beckstead cultured this fungus, Pyrenophora semeniperda, in the laboratory and developed an experimental field application that, in some trials, killed all the dormant soil-banked Bromus seeds, leaving none to germinate the following year. The team’s work opens the way to a commercial biocontrol product that may be capable of safely eliminating the seed bank of persistent invasive grasses. Biocontrol could be used in conjunction with other weed control measures and conservation strategies to make sagebrush-steppe lands less susceptible to re invasion. A biocontrol tool effective against Bromus seeds would be a boon to managers working to restore the native bunchgrasses, forbs, and shrubs that characterize an intact shrub-steppe ecosystem.
Image Source: Joint Fire Science Program