Early detection of invasive exotic insect infestations using eDNA from crop surfaces

The number of exotic species invasions has increased over recent decades, as have the ecological harm and economic burdens they impose. Rapid‐response eradication of nascent exotic populations is a viable approach to minimizing damage, but implementation is limited by the difficulty of detecting such species during the early stages of infestation due to their small numbers. The use of environmental DNA (eDNA) has helped address this issue in aquatic ecosystems, but to the best of our knowledge has not been trialed for surveillance of exotic species in terrestrial systems. Using a high‐resolution, real‐time (quantitative) polymerase chain reaction assay, we developed a highly efficient protocol to survey agricultural fields for the invasive non‐native brown marmorated stink bug (BMSB; Halyomorpha halys ). We compared results using eDNA to those for conventional monitoring traps and documented substantially higher sensitivity and detection effectiveness. Our methodology is transferable to situations in which the DNA of terrestrial target species can be accumulated into a single substrate, suggesting that eDNA‐based approaches could transform our ability to detect exotic insects in non‐aquatic settings.