Field studies were conducted in 2002 and 2003 in New Jersey to determine the length of time after a bispyribac-sodium application at which creeping bentgrass, Kentucky bluegrass, and perennial ryegrass can be safely reseeded. Bispyribac at 148 or 296 g ai/ha was applied 6, 4, 2, or 1 week before seeding (WBS). Bispyribac at 148 g/ha applied 1 WBS reduced ground cover of creeping bentgrass and Kentucky bluegrass at 3 weeks after seeding (WAS) by 30 and 42% as compared to the nontreated check, respectively. Reductions in Kentucky bluegrass and creeping bentgrass ground cover from bispyribac at 296 g/ha applied 1 WBS were evident at 28 WAS, whereas perennial ryegrass recovered from initial reductions in ground cover by this time. Applications made 6 to 2 weeks before seeding did not adversely affect ground cover of any species at any evaluation date as compared to the nontreated check. These studies suggest creeping bentgrass, Kentucky bluegrass, and perennial ryegrass can be safely reseeded 2 weeks after a bispyribac application. However, ground cover may be reduced by bispyribac applied 1 WBS.

Nomenclature: Bispyribac-sodium; creeping bentgrass, Agrostis stolonifera L. ‘L-93’; Kentucky bluegrass, Poa pratensis L. ‘Kenblue’; perennial ryegrass, Lolium perenne L. ‘Pizzazz.’

Abbreviations: ALS, acetolactate synthase (EC 2.2.1.6); SE, standard error; WAS, weeks after seeding; WBS, weeks before seeding.