Evaluation of a Fungicide Application as Influenced by Spray Nozzles for Rhizoctonia Blight Management in Cool-Season Turfgrass Lawns

Increased utilization of tall fescue (Schedonorus arundinaceus [Schreb.] Dumort) in residential lawns is due to enhanced drought tolerance and minimal problems with insect pests. Rhizoctonia blight (Rhizoctonia solani Kühn) or “brown patch”, however, is a persistent disease of tall fescue lawns during summer months. The objective of this research was to evaluate a new fungicide [Mural 0.45WG active ingredients (a.i.’s: azoxystrobin and benzovindiflupyr)] for Rhizoctonia blight control in tall fescue as influenced by spray nozzle type. The fungicide was applied once to tall fescue in Ohio (OH) and Pennsylvania (PA), in both preventive and curative field trials. Three different spray nozzles were used to produce different spray droplet sizes (TurfJet 1/4TTJO4 = extremely coarse; Air Induction 8004 = very coarse; and XR TeeJet 8008 = coarse). Disease control and turfgrass quality were evaluated for a 63-day period after application. The fungicide, when applied using spray nozzles that produced either coarse or very coarse droplets, provided ≥42 days of preventive and curative disease control at both sites. Overall, better turfgrass quality was related to better disease control also at both sites. This offers value for turfgrass industry professionals as well as allowing for reductions in drift and non-target environmental problems. Species used in this study: tall fescue, Schedonorus arundinaceus (Schreb.) Dumort. Chemicals used in the study: Mural 0.45WG (active ingredients a.i.’s: azoxystrobin and benzovindiflupyr).