Seeded Bermudagrass Establishment in an Overseeded Perennial Ryegrass Stand as Affected by Transition Herbicide and Seeding Date

It has been demonstrated that improved cultivars of seeded common bermudagrass (Cynodon dactylon L. Pers.) can be dormant-seeded during the winter, providing an alternative approach to renovate damaged areas of turf. However, bermudagrass golf courses and athletic fields are often overseeded with a cool-season grass such as perennial ryegrass (Lolium perenne L.) during the dormancy period and the overseeded grass may prevent or delay establishment of dormant-seeded bermudagrass. The objective of this study was to determine if dormant seeding into an overseeded turf could be an effective means of bermudagrass establishment. ‘Riviera’ bermudagrass was seeded into a simulated overseeded turf on three different dates, including March (dormant seeding), April (spring seeding), and June (summer seeding) in 2008 and 2010 at Fayetteville, AR. In addition, five herbicides, including glyphosate, flazasulfuron, foramsulfuron, trifloxysulfuron, pronamide, and an untreated control, were applied to each of those seeding date treatments to alter the competition from the perennial ryegrass. Bermudagrass establishment was enhanced by herbicide application, but less affected by seeding date. Glyphosate applied before seeding provided the highest bermudagrass coverage compared to the other herbicide treatments and sulfonylurea herbicides were also effective at suppressing ryegrass competition compared to pronamide and untreated plots. Establishment of seeded bermudagrass into an overseeded stand of perennial ryegrass turf was improved with herbicide use, regardless of the seeding date. However, there was no advantage to dormant seeding bermudagrass into an overseeded turf.