How to achieve effective bentgrass control on lawns

By Lisa Beirn, Ph.D., technical services manager, Syngenta

Creeping bentgrass is a cool-season perennial grass that is commonly used on golf course greens, tees and fairways. It is often considered a weed when found in lawns. Bentgrass spreads by producing above ground stems (stolons) that grow close to the ground. In lawns, this growth habit can outcompete desirable species and result in areas of dense, patchy turf that may appear puffy.

Tenacity® herbicide is a systemic herbicide for pre- and post-emergent control of grass and broadleaf weeds in several cool- and warm-season turf species. The active ingredient, mesotrione, is based on a naturally occurring compound produced by the bottlebrush plant (Callistemon citrinus). In susceptible plant species, Tenacity prevents the formation of pigments called carotenoids. Carotenoids are essential for photosynthesis and help protect plants from sun damage. Without carotenoids, chlorophyll and cell membranes are destroyed, resulting in bleaching of leaves and plant death.

Bentgrass (Agrostis spp.) and other tough to kill grassy weeds, such as nimblewill (Muhlenbergia spp.) and windmillgrass (Chloris spp.) are sensitive to Tenacity. Multiple applications can selectively remove these grasses from Kentucky bluegrass, tall fescue and perennial ryegrass. Coupled with a re-seeding program in the late summer or early fall, lawns can be converted to the desirable turf species.

It is recommended to apply Tenacity at 4-5 fl. oz./A on a two- to three-week interval for three applications. Lawn seeding can occur after the second application of Tenacity. Depending on location, applications of Tenacity starting in August or early September will best coincide with a re-seeding program for optimum turf conversion.

Below is a summary of Tenacity trials from across the U.S. over several years.

Trial sources: Illinois, Indiana, Iowa, South Carolina, Virginia and Washington, 2005-2007.

Tenacity is available in a convenient 8-oz. bottle that lets you measure the exact dosage without the need for a syringe.

For more information about bentgrass control, contact your local Syngenta territory manager.

© 2023 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. Tenacity® and the Syngenta logo are trademarks of a Syngenta Group Company.

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