Development of a Field-Deployable Loop-Mediated Isothermal Amplification Assay for the Rapid Detection of Erysiphe corylacearum in Hazelnut

Erysiphe corylacearum, the causal agent of powdery mildew in hazelnut (Corylus avellana L.), has become an emerging pathogen of concern in Italian hazelnut production requiring rapid and accurate detection to support timely disease management and phytosanitary measures. We developed and validated a field-deployable loop-mediated isothermal amplification (LAMP) assay for the specific detection of E. corylacearum and evaluated three primer sets targeting the Internal Transcribed Spacer (ITS) region, RNA polymerase II second largest subunit (rpb2), and glutamine synthetase (GS) genes; the GS-targeting Ecg set showed the highest sensitivity and specificity. The assay was shown to be sensitive down to 200 fg of fungal DNA, efficiently detected E. corylacearum from diluted crude leaf extracts, and produced results within half an hour, allowing the detection of latent infections before visible symptoms emerged. On-site validation with a portable LAMP instrument showed the assay’s suitability for field-deployable diagnosis and early-warning applications in hazelnut orchards.