Development and Comparison of a <scp>LAMP</scp> Assay With <scp>PCR</scp> ‐Based Methods for Detecting <i>Armillaria mellea</i> in Soil and Root Samples

ABSTRACT Armillaria mellea is the soil‐borne fungal pathogen responsible for root rot in numerous woody plants. Its early detection in nurseries and orchards is essential for effective disease management and for limiting pathogen dissemination. In this study, a loop‐mediated isothermal amplification (LAMP) assay was established and validated for the sensitive detection of A. mellea in soil and root samples. The assay focuses on the translation elongation factor 1‐α ( tef1 ) gene and was evaluated alongside conventional PCR, nested PCR and real‐time PCR methods. The optimal LAMP reaction was conducted at 60°C for 60 min, and the amplification products were assessed by agarose gel electrophoresis and visualised using GelGreen fluorescence under UV light. The sensitivity of the LAMP assay reached 0.1 fg μL −1 of genomic DNA, demonstrating superior sensitivity over real‐time PCR, nested PCR and conventional PCR methods. Field samples collected from both symptomatic and asymptomatic trees in orchards further supported the excellent performance of the assay. A. mellea was detected in all infected samples and even in a few asymptomatic soils that were negative using other diagnostic methods. Based on its high sensitivity, specificity, rapid time to result and minimal equipment requirements, the developed LAMP assay is a promising diagnostic tool for the early detection of A. mellea in nurseries and natural ecosystems. Its practical application could facilitate proactive pathogen monitoring and help control the establishment and spread of Armillaria root rot disease, particularly in response to elevated environmental pressure and climate change.