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Oral: Isothermal Pathogen Detection


LAMP lights the way: early detection of airborne inoculum of Magnaporthe oryzae in turfgrass fields
F. PEDUTO HAND (1), F. Peduto Hand (1), C. Villari (1), W. Mahaffee (2), T. Mitchell (1) (1) The Ohio State University, U.S.A.; (2) USDA-ARS, U.S.A.

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A host-specialized form of Magnaporthe oryzae (Lolium pathotype, MoL) is the causal agent of Grey Leaf Spot (GLS), a detrimental disease of perennial ryegrass. Early diagnosis of this disease is crucial for making timely management decisions. A pathogen-specific quantitative loop-mediated isothermal amplification (LAMP) assay, that is able to detect as low as 25 spores of the pathogen, was developed in our laboratory to monitor GLS airborne inoculum. To assess the suitability of the method for field use, two perennial ryegrass plots were artificially inoculated with pathogen-infested dried grass clippings at The Ohio State University Turfgrass Research Center in the summer of 2015, and five continuously running custom impaction spore traps were placed in each plot. Sampling units were replaced daily and tested with the developed qLAMP assay while plots were monitored for symptom development. Results confirmed that the qLAMP assay-trap system was able to detect the pathogen's inoculum up to two weeks before symptoms developed in the field. The implementation of this assay by practitioners has the potential to be a useful decision support tool to guide initiation and timing of fungicide applications for GLS management.