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POSTERS: New and emerging diseases

Bermudagrass Decline: A Complex Disease
Matthew Tucker - Mississippi State University. Maria Tomaso-Peterson- Mississippi State University, Jonas King- Mississippi State University, Terry Spurlock- University of Arkansas, Aline Badial- Mississippi State University

Gaeumannomyces graminis (Gg) is understood to be the causal agent of bermudagrass decline (BD), however a complex of ectotrophic root-infecting (ERI) fungi were identified by Vines (2015) at Mississippi State University. To investigate the natural occurrence of an ERI complex in bermudagrass putting greens, two greens at Mississippi State University Golf Institute were selected. One green was symptomatic for BD and the other asymptomatic. A fishnet grid was designed using ArcGIS to overlay each green to establish areas of interest (AOI). A summer core aerification provided root material for each AOI to detect ERI fungi using genomic DNA and multiplex qPCR. Fungi of interest included Gg, an undescribed Gaeumannomyces sp. (Gsp), Magnaporthiopsis cynodontis (Mc), and the novel Candidacolonium cynodontis (Cc). A four-fungal complex was present in 8% of AOIs within the BD green. Gg had the greatest number of DNA copies (# DNA) within 80% of AOIs while Cc had the greatest # DNA in the remaining 20% AOIs. This complex was also present within 7% of AOIs on the asymptomatic green. However, Gsp had the greatest # DNA within 80% AOIs and again Cc had greatest # DNA in the remaining 20%. Various combinations of the four ERI fungi were widespread within AOIs for both greens confirming the natural occurrence of an ERI fungal complex associated with bermudagrass roots. This may lead to the decline of affected turf. The impact on plant health will be evaluated in future analyses.