RELATIVE FITNESS OF GLYPHOSATE RESISTANT CREEPING BENTGRASS CULTIVARS IN KENTUCKY BLUEGRASS

Creeping bentgrass is a widely used turfgrass species on golf course greens, tees, and fairways in the northern United States. A disadvantage of creeping bentgrass is its vulnerability to a wide range of pest problems. Annual bluegrass is a serious weedy grass problem on creeping bentgrass putting greens1. No herbicide chemis-try is available to control, effectively and selectively, annual bluegrass in creeping bentgrass. Glyphosate, the active ingredient in Roundup ® brand herbicides is a broad spectrum herbicide that is toxic to plants, fungi, and bacteria2. Glyphosate resistant crops have been developed by genetically engineering plants with a gene that codes for an EPSP synthase protein with lower sensitivity to glyphosate3. The Monsanto and Scotts Companies have collaborated in the development of genetically engineered creeping bentgrass cultivars that are resistant to glyphosate via the heterologous expression of a gene from the CP4 strain of Agrobacterium sp. encoding for a glyphosate resistant form of EPSP. Adoption of glyphosate resistant creeping bentgrass could potentially simplify and improve control of a wide array of invasive annual, biennial, and perennial grass, broadleaf, and sedge species that can invade golf turf. The availability of glyphosate as an over-the-top treat-ment on glyphosate resistant creeping bentgrass could significantly reduce the need for many of these herbi-cides, resulting in several important environmental, health, and safety benefits. It isless likely to leach than most other turf herbicides. It has low toxicity to mammals, birds, and fish, and it is one of the few commerciall