Rapid assay using recombinase polymerase amplification and lateral flow dipstick for identifying Agrilus mali (Coleoptera: Buprestidae), a serious wood-boring beetle of the western Tianshan Mountains in China.

Agrilus mali stands as a significant wood-boring pest prevalent in Northeast Asia. Identifying this pest beetle is often hindered by insufficient efficient, rapid, on-site discrimination methods beyond examining adult morphological features. As a result, an urgent need arises for developing and implementing a rapid and accurate molecular technique to distinguish and manage the beetle. This study presents a straightforward, swift, highly specific, and sensitive method built upon recombinase polymerase amplification combined with a lateral flow dipstick (RPA-LFD). This method demonstrates the capability to promptly identify the beetle, even during its larval stage. RPA primers and probes were designed using the internal transcribed spacer 1 region. Through probe optimization, false-positive signals were successfully eliminated, with an accompanying discussion on the underlying causes of such signals. The RPA-LFD assays exhibited remarkable specificity and sensitivity, requiring as little as 10-3 ng of purified DNA. Furthermore, the extraction of crude DNA was achieved through immersion in sterile distilled water, thus streamlining the assay process. Achievable at temperatures ranging from 30 to 50 °C, the RPA-LFD assay can be executed manually without specialized equipment. By merging the RPA-LFD assay with DNA coarse extraction, A. mali can be detected within just 30 min. This current study effectively demonstrates the immense potential of RPA-LFD in quarantine and pest management. Additionally, it presents a universal technique for the rapid on-site diagnosis of insects, showcasing the wide applicability of this method.