Cultivar Response of Seeded Bermudagrass to Leaf Spot and the Influence of Nitrogen on Disease Severity

Abstract

Seeded bermudagrass [Cynodon dactylon (L.) Pers.] cultivars are currently replacing hybrid-bermudagrass and cool-season turfgrasses in some golf course renovations, home lawns, and athletic fields. Leaf spot, a destructive disease of bermudagrass, is caused by a fungal complex consisting of Bipolaris and Exserohilum spp. that infect leaves, stems, and stolons resulting in leaf blight and melting-out. A three-year field study was conducted to determine the response of seven seeded bermudagrass cultivars to leaf spot and the influence of nitrogen on leaf spot severity. Princess-77, Riviera, and Yukon were determined to have improved field tolerance to leaf spot. Transcontinental and Savannah cultivars displayed moderate disease response while Nu-Mex Sahara and Arizona Common had poor field tolerance to leaf spot. Seeded bermudagrass cultivars with poor field tolerance to leaf spot displayed increased leaf spot severity in response to high nitrogen (2.0 lb N per 1000 ft2 per month). Leaf spot severity of Arizona Common increased at the highest nitrogen level. Nitrogen levels did not influence leaf spot severity in seeded bermudagrass cultivars that had improved field tolerance. Princess-77, Riviera, and Yukon had the lowest leaf spot severity throughout the growing season each year of the three-year study.