Turf-Type Tall Fescue Brown Patch Resistance as Influenced by Morphological Characteristics

Abstract

Brown patch (caused by multiple species of Rhizoctonia and Rhizoctonia-like fungi) is one of the major turfgrass diseases impacting turf-type tall fescue [ Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.] lawns during the summer season. Selection of tall fescue cultivars with brown patch resistance is an important cultural management practice to reduce disease severity and limit reliance on fungicides. A greenhouse experiment was conducted to quantify differences in brown patch resistance among 15 tall fescue cultivars and correlate disease resistance with plant morphological characteristics. Prior to R. solani inoculation, leaf blade width, sheath width and length, endophyte stem infection, and relative growth rate were measured. Disease resistance was determined as a percentage of the canopy blighted as measured using digital image techniques. Brown patch severity after 21 days in Experiments 1 and 2 ranged from 36.7 to 72.7% and 20.8 to 41.8%, respectively, among all cultivars. There were significant differences among morphological characteristics for the cultivars. Increased brown patch was associated with cultivars with a faster growth rate, wider sheath width, and decreased sheath length. This study demonstrates the importance of cultivar selection for reducing brown patch severity in tall fescue lawns. Additionally, tall fescue cultivars with higher shoot density and narrow leaves should not be avoided due to concerns of increased brown patch susceptibility.