Evaluation of oxygenated and ozonated nanobubble water treatments for dollar spot suppression in seashore paspalum

Abstract

Dollar spot (caused by Clarireedia spp.) is the most commonly occurring turfgrass disease on golf courses in North America, and current disease control programs rely on frequent fungicide applications. The escalating occurrence of fungicide resistance in Clarireedia spp. populations, coupled with the reduction of the annual kilograms active ingredient applied per hectare for some fungicides, emphasizes the need for alternative management strategies. The use of oxygenated or ozonated water treatments has been effective as a component of an overall plant disease management strategy. In field and growth chamber-controlled environment trials, the impacts of oxygenated and ozonated nanobubble water treatments were evaluated for turf quality and dollar spot control in seashore paspalum (Paspalum vaginatum Swartz). Despite generating relatively high levels of dissolved oxygen (40 mg L⁻¹) or ozone (ca. 8 mg L⁻¹) in water treatments through nanobubble aeration in all trials, these treatments did not cause damage to seashore paspalum tissues, but were unsuccessful in controlling dollar spot. Additionally, tests comparing two different application methods (soil drench versus foliar spray) for all treatments suggested that the application method had no effect on treatment efficacy. Overall, oxygenated and ozonated nanobubble water treatments did not adversely affect seashore paspalum turf quality and were ineffective in suppressing dollar spot in field and growth chamber trials.