Evaluation and Utilization of Allelopathic Festuca rubra Turfgrass Cultivars and Selected Groundcovers for Alternative Weed Management Strategies in the Landscape 2000
Principal Investigator: Leslie A. Weston, Department of Horticulture, Cornell University
Cooperators: Cecile Bertin, graduate student in Horticulture; Andrew F. Senesac, extension educator, Long Island Horticultural Extension and Research Center, Riverhead NY; Dr. Frank Rossi, turf specialist, Department of Horticulture; Agnes Rimando, natural products chemist, USDA National Center for Natural Products, Oxford MS.
The development of alternative weed management strategies in landscape and turf settings involves the use and implementation of novel bio-control practices which can provide efficaceous control over the course of the growing season. Use of pathogenic organisms to control weeds has not proven particularly effective, due to problems in obtaining consistent control and difficulty in formulation of biocontrol organisms. Organically derived products, such as corn gluten or cramby meal, have also not provided consistent or inexpensive control, especially in commercial settings such as golf courses, parks and athletic fields where complete control is often desirable. One novel approach which shows strong potential is the selection, development and use of allelopathic or weed suppressive turfgrasses or groundcovers to naturally control annual weeds in the landscape, without the use of herbicides. Fescues, especially Festuca rubra spp., produce secondary products known as allelochemicals with potent ability to suppress weed seed germination and growth. A collection of fescues was established as part of the NTEP trials at Cornells turf farm in 1998. Quality and weed suppressive ability were evaluated by C. Bertin in both 1999 and 2000. Of the 80 cultivars evaluated, nine cultivars were identified that provided greater than 90% weed suppression as compared to other cultivars in 1999. Iin 2000, seven of these same cultivars were also extremely weed suppressive, showing that despite variability in season weather patterns, the weed suppressive trait remains active in selected cultivars. Laboratory and field research was conducted to determine which fescue cultivars are consistently most weed suppressive in field and laboratory settings and the mechanisms of suppression. Results from the laboratory and field trials, along with new plots recently established in Ithaca and Riverhead NY will determine which fescue cultivars can be successfully established and maintained with fewest invasive weeds in Central NY and Long Island NY growing conditions. A weed suppressive index will be determined for the materials under evaluation, based on growth measurements obtained. Long term studies are now underway to evaluate the allelochemicals, secondary metabolic pathways and genes involved in this suppressive trait in selected fescue cultivars. Recommendations will be developed for cultivar and species selection, seeding or planting rate and mowing height.