Certain turfgrass species exhibit the ability to produce large quantities of root exudates which contain bioherbicides or natural products which are highly effective weed suppressive agents. After many years of field and laboratory research, we have identified specific cultivars of fine leaf fescue which are highly allelopathic or weed suppressive. We have developed recommendations for landscape managers as to which cultivars to select, planting rates and maintenance requirements for optimal performance. We have identified a novel allelochemical which is a potent inhibitor of seedling growth in higher plant species, and identified cultivars and species of fescue which produce this inhibitor. We have obtained an international patent for m-tyrosine, the novel inhibitor associated with weed suppression in fescue species. We have investigated the mode of action and soil persistence of this compound and fescue root exudates in general. We are now working to investigate the potential to select and breed turfgrasses with greater inherent weed suppressive activity with our colleagues at the University of Rhode Island. In addition, we are exploring the potential to develop m-tyrosine or related chemistry as novel soil-applied organic herbicides with the agrichemical industry. Currently, we have numerous demonstration trials with weed suppressive fescues and mixtures of turfgrasses around the state. We are working with the NYSDOT to modify recommendations for establishment of weed suppressive turfgrasses for use along major highways and roadsides, and are in the process of completing a handbook and website for use by NYSDOT personnel.Since they are the major manager of most of the turfgrass in NY State, this research will signficantly impact maintenance and establishment of the majority of managed turf in NY State.

The great interest in reducing application of herbicides in landscape and turf settings has resulted in a strong need for alternative pest management strategies that work in the landscape. Due to the lack of availablity of effective organic products or alternative strategies for weed management in turfgrass settings, the selection of crops and groundcovers which are inherently weed suppressive is of increasing importance in the landscape. Utilization of low maintenance weed suppressive turfgrasses and sods is of interest to commercial turfgrass and sod producers, landscape managers, golf course and athletic field managers, and especially roadside and home landscape managers.

We have evaluated over 90 cultivars of Festuca spp., and over 20 additional species of warm and cool season turfgrasses for their ability to suppress weeds and tolerate stressful growth conditions when managed in low maintenance settings. We have determined that several cultivars of fine fescues exhibit a remarkable ability to suppress annual and perennial weeds in turf settings over multiple years and locations across NY State. We have collected large quantities of fine leaf fescue root exudates and determined that production of these inhibitory exudates is localized in the epidermal cell of living fibrous root tips of certain fine fescues. We have identified the biologically active constituent of the exudates of fine leaf fescues and this structure is a novel amino acid analogue, presenting great potential for use a bioherbicide itself or for trait incorporation into other less suppressive turfgrasses. We currently have a provisional patent for this finding with Cornell`s research foundation. We are now working with a turf breeder, Dr. Rebecca Brown at URI to select for enhanced weed suppression in commercial turfgrasses,including fine fescues and closely related perennial ryegrasses. The production of bioactive root exudates could be enhanced in other festuca cultivars by traditional breeding or molecular approaches. The bioactive molecule identified exhibits characteristics of growth suppression at very low concentration, similar to commercial preemergent herbicides currently on the market. It also exhibits selectivity for control of annual and perennial turf weeds,but is not persistent over long time frames in soil settings. The Scotts Company is currently evaluating the market potential for producing an organic herbicide for residential applications. In addition, we have examined other species of weed suppressive low maintenance conservation grasses for use along roadsides and in conservation areas, and have found several excellent performers for low maintenance, low fertility settings. Numerous roadside and conservation trials are underway across NY State to validate our research findings. This information is of particular importance to landscape and roadside managers as well as conservationists and homeowners.

We have demonstration trials of weed suppressive fescues around NY State at this time and in conjunction with NYSDOT. We anticipate the development of weed suppressive cultivars of fine leaf and other fescues with enhanced ability to suppress weeds. In addition,the bioactive root exudates and novel compound identified may provide a unique opportunity to further develop unique natural bioherbicides for weed suppression in the home and commercial landscape.

weed science, integrated pest management

New York State Department of Transportation, The Scotts Company

• Andrew Senesac (Suffolk County Cooperative Extension)
• Rebecca Brown (University of Rhode Island)
• Robert Baker (Scotts Company)
• Jerrold Meinwald (Department of Chemistry)
• Frank C. Schroeder (Department of Chemistry)
• Cecile Bertin (McGill University)
• Jeff Weidenhamer (Ashland University)