Top: probability of detecting eDNA from emerald ash borer (Agrilus planipennis; EAB) using the tree core sampling method at sites in New Jersey, USA over time. Bottom: the number of ash tree core samples needed per tree to ensure 95% confidence in detection of EAB larval presence within a tree. Time is represented as growing degree day (GDD) accumulation, base 50 °F (10 °C). Black lines represent the posterior medians from a Bayesian general additive model (GAM); grey shading indicates 80% and 95% credible intervals. Black circles show the proportion of samples with detections on each sampling date calculated from the raw data.