Detection of spp. in Golf Course Irrigation Systems.

Many spp. are causal agents of diseases of turfgrasses. spp. disseminate through irrigation systems in agricultural settings, and this study provides evidence that spp. also disseminate through golf course irrigation. Water samples were collected from irrigation heads and water sources at 10 golf courses in Missouri and Kansas, U.S.A. Samples were collected from 2018 to 2019 in April, July, and October. Phosphorus, nitrogen, and chloride concentrations were measured from irrigation head samples to determine if these parameters influence frequency of spp. detected. spp. were detected in samples through baiting and membrane filtration. Cultures were isolated on PARP media, and DNA was extracted from putative isolates. The internal transcribed spacer region was PCR-amplified and sequenced. Phylogenetic trees were constructed using representative sample sequences, sequences from seven morphologically identified reference isolates of , and similar GenBank accessions. Detected oomycete species include , , , , , and . Twenty-one clades lacked species-level resolution, and 14 of these clades were associated with species. Clades A, C, D, E, I, and M contain species that cause root and crown rot on creeping bentgrass. Detected communities were dependent on the detection method used and sampling source. frequency and diversity were highest in April 2019. Sample temperature, sampling site, and chloride and nutrient concentrations did not influence frequency in samples. Irrigation systems using surface water sources contained at least three spp. over the course of 2 years.