Black Fingers of Death - the Bane of Cheatgrass
Cheatgrass (Bromus tectorum) is an invasive plant affecting rangelands across the Intermountain West. Even after the successful removal of germinated seeds and established plants, ungerminated seeds in the soil can carry over across years and hamper the establishment of desired native plants. Rocky Mountain Research Station scientists have been addressing these issues, with focus on the ecology, population biology, and evolutionary genetics of both cheatgrass and its fungal pathogens.
Biocontrol using naturally occurring fungal pathogens is a novel approach that can be a valuable tool for use in conjunction with other control methods. Currently, the most promising biocontrol organism under study is an ascomycete seed pathogen that can kill dormant cheatgrass seeds and sometimes a high proportion of germinable seeds. This pathogen (Pyrenophora semeniperda) has been dubbed Black Fingers of Death because of the fingerlike, black fruiting bodies that protrude from killed seeds. Because Black Fingers of Death is a generalist pathogen, research has included a careful evaluation of its effects on non-target host seeds under realistic field application scenarios. In some field inoculation treatments with the pathogen, complete control of the dormant carryover seed bank has been achieved, and negative impacts on subsequently seeded native grasses were minimal. This research shows that seed pathogens can have important application in the control of weed seed banks in production agriculture as well as on rangelands. Because of these studies, the goal of a practical, safe, and cost-effective commercial product for cheatgrass carryover seed bank biocontrol on rangelands is now potentially within reach. A patent application process for this biocontrol agent has been initiated through the Forest Service Patenting and Licensing Program, and collaboration with an industry partner to develop a marketable product is on track to begin soon. For publications and more information, please visit: http://www.fs.fed.us/rm/grassland-shrubland-desert/research/projects/cheatgrass-biocontrol.