Non-destructive diagnosis of ambrosia beetle attacks via detection of the associated tree pathogens

Ambrosia beetles have become major threats to forest ecosystems, often vectoring pathogenic fungi and causing severe tree mortality. Early infestations produce only a few frass-filled pinholes, making species identification difficult without destructive sampling, which may further attract beetles. We developed a non-destructive detection method based on the specific fungal symbionts of Platypus quercivorus ( Dryadomyces quercivorus ) and Euwallacea interjectus ( Fusarium kuroshium ). Plastic inoculating needles inserted into beetle pinholes allowed sampling without injuring trees. Fungal detection was achieved through either fungal isolation, or direct DNA analysis using species-specific primers for both symbionts. This approach enables reliable, non-destructive identification of ambrosia beetles through their associated fungi. We developed a non-destructive method that detects species-specific fungal tree pathogens of wood‑boring ambrosia beetles using plastic inoculating needles, enabling indirect identification of the associated beetle species. For fungal detection, we confirmed the utility of species-specific primers for Fusarium kuroshium and developed a species-specific probe for Dryadomyces quercivorus . This study provides the first report of non-destructive detection and identification of ambrosia beetles through their associated tree pathogens.