Early detection of the oak wilt fungus (Bretziella fagacearum) using trapped nitidulid beetle vectors

Abstract

AbstractAs the range of the oak wilt fungal pathogen expands, it will become increasingly important for land managers to have early detection tools to find the disease before it becomes locally established and causes environmental and economic losses. New York State has been at the leading edge of the disease's range since 2008 and intensively surveys for and manages the disease to protect the state's oak resource. The oak wilt fungus was successfully detected using double‐nested PCR on nitidulids wet‐collected in multi‐funnel traps, suggesting we can find it on the landscape before symptomatic trees are detected. From 2019 to 2021, 10–13 percent of beetle samples were PCR positive for the oak wilt fungus, including sites in New York where oak wilt had been treated and ‘early detection’ sites where infected trees had never been found. Our method is also useful for identifying local associates, such as Carpophilus lugubris in New York. While some obstacles exist, such as the efficiency of sampling and the ability to trace positive nitidulid samples back to infected trees, with more development this tool will be another useful option for land managers in detecting and managing oak wilt.