A Community Analysis of Plant-Parasitic Nematodes on Coastal Oregon Golf Course Putting Greens

Plant-parasitic nematodes (PPN) are important pests affecting golf course putting greens. Recently, PPN have become a pest of concern in the Pacific Northwest (PNW), but relatively little information exists on the species present or their distribution across the region. A survey and community analysis of PPN across five independently managed golf courses in Southwest Oregon was conducted. In 2023, soil samples were collected from 30 putting greens in January, May, August, and November. Nematodes were extracted using Baermann funnel and mist extraction methods and identified using morphological and molecular methods. PPN community diversity measures were assessed. Permutational multivariate analysis of variance testing indicated significant differences in PPN communities among season, course, and extraction method. Helicotylenchus and Meloidogyne were the most frequently encountered PPN, with maximum population densities of 20,776 and 59,100 nematodes per 100 cm³ soil, respectively. Indicator species analysis revealed Meloidogyne as a PPN of concern at three of the courses, particularly in January when population densities were highest just prior to reported damage. Representative populations from each course were collected for speciation. Two PPN species were identified at all courses, Helicotylenchus pseudorobustus and Meloidogyne naasi, whereas other species were found to be course specific. An unidentified species of Heterodera was recovered from mixed stand putting greens. This is the first survey of golf course putting green PPN communities across multiple seasons in the PNW. With an increase in damage symptoms reported in this region, there is a need for further assessment of PPN impacts on PNW golf courses.