When frass meets gold: development of a TaqMan Probe-Based qPCR for identifying goldspotted oak borer, Agrilus auroguttatus Schäffer

This study presents a qPCR-based molecular diagnostic method utilizing a TaqMan probe to ac-curately identify Agrilus auroguttatus Schäffer (Coleoptera: Buprestidae) from adult insects, ex-creta samples, and frass residues. The method demonstrated excellent DNA amplification across all sample types, highlighting strong analytical specificity. The protocol exhibited high repeata-bility and reproducibility, with inter-run and intra-run variability standard deviations consist-ently at or below 0.5. This assay distinguished A. auroguttatus samples from non-target species with 100% sequence correspondence. Analytical sensitivity (LoD) for adult and frass samples was determined at 8 pg/µL and at a 1:5 dilution from an initial concentration of 5 ng/µL, yield-ing mean Cq values of 35.14 ± 0.71 and 37.07 ± 0.59, respectively. The indirect diagnostic capabil-ity of this method is particularly valuable for detecting the presence of wood-boring insects, po-tentially aiding in the early detection of A. auroguttatus in new environments or in managing cur-rent outbreak areas. This diagnostic tool could thus play a critical role in biosecurity efforts to limit the spread of this invasive species.