Emerald ash borers have carved a deadly path through North America’s ash trees, leaving foresters with few practical options at large scales. Now, scientists in Minnesota have uncovered an unexpected ally already living in those forests: native fungi that can rapidly kill the invasive beetles. In lab tests, four locally sourced fungal strains cut emerald ash borer survival to just a few days, pointing to a new, biologically based way to slow the pest’s spread. The research was led by Colin Peters, a graduate researcher in plant pathology at the University of Minnesota. The emerald ash borer, an invasive beetle from East Asia, has already killed millions of ash trees across North America. Since it was first detected near Detroit, the insect has spread to 37 U.S. states and six Canadian provinces. …The study is published in the journal Forests.