Preparing for the arrival of a highly invasive beetle in Switzerland

In the face of intensified global trade, the number of invasive species introductions has drastically increased. Consequently, the early detection and containment of these species have gained importance. The invasive emerald ash borer (EAB) has killed millions of ash trees in North America and is quickly spreading toward Central Europe, calling for effective infestation screening approaches for Switzerland. Unfortunately, the emergence of visible tree-stress symptoms occurs only several years after the borer's arrival and are hard to tell apart from those caused by soil drought. Here, we explore the potential of reflectance spectroscopy, as a novel and efficient method for the previsual detection of EAB induced stress in well-watered and drought-stressed trees, with the aim to understand whether different stressors can be distinguished. We further investigate the linkage between spectral variation and adjustments in leaf biochemical composition upon infestation.