Identification, Population Dynamics, and Vertical Distribution of Plant-Parasitic Nematodes in South Florida Golf...

In South Florida, the development and maintenance of high-quality golf courses are important to the state's economy. The courses, however, are commonly affected by plant-parasitic nematodes (PPNs), which are highly damaging. Effective nematode management is reliant on accurate population and identification data to understand when and where population peaks occur. However, little data are available on turf-dwelling nematode population changes in southern Florida golf courses, often leaving golf course superintendents without the critical data needed to properly implement response strategies. The goal of this research was to determine the annual population fluctuations of PPNs in southern Florida golf courses and the impact of environmental, edaphic, and soil depth factors on PPN populations. Monthly soil sampling and monitoring of edaphic and environmental factors were conducted from October 2022 to October 2023 at four golf course locations on the east and west coasts of southern Florida. Nine PPN genera were identified, among which Hoplolaimus galeatus (lance nematode), Belonolaimus longicaudatus (sting nematode), and Meloidogyne graminis (root-knot nematode) are known to cause significant damage to turfgrass, and their identification was confirmed through molecular and phylogenetic analyses. Nematode population fluctuations differed between locations. An April population peak was observed for sting, root-knot, and lance nematodes at West Coast locations, with relative summertime lows. In the East Coast locations, PPN population peaks were observed in September and October. In all locations, nematodes largely resided in the upper soil stratum (0-10 cm). No significant difference was detected between changes in edaphic factors and PPN community composition. These findings can potentially inform targeted management interventions, such as nematicide application, to optimize PPN control in turfgrass systems.