Evaluation and Utilization of Allelopathic Festuca rubra Turfgrass Cultivars for Alternative Weed Management Strategies 2002
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 Research and Extension Center, Riverhead NY; Dr. Frank Rossi, turf specialist, Department of Horticulture; Peder Weibull, Swalof Weibull seed company, Sweden.
Abstract: 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 effective 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 and other related 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. In 2000, seven of these same cultivars were also extremely weed suppressive, showing that despite variability in seasonal weather patterns, the weed suppressive trait remains active in selected cultivars. Laboratory and field research was conducted to determine which fescue cultivars were consistently most weed suppressive in field and laboratory settings and the mechanisms of suppression. Results from the laboratory and field trials, along with plots established in Ithaca and Riverhead NY in 2000 have shown that cultivars Intrigue, Reliant and Oxford can be most successfully established and maintained with fewest invasive weeds in Central NY and Long Island NY growing conditions. The cultivar Treasure, on the other hand, was exceptionally weedy and poorly established in both locations. A weed suppressive index will be determined for the materials under evaluation, based on growth measurements obtained. Longterm studies are now underway to evaluate the allelochemicals, secondary metabolic pathways and genes involved in this suppressive trait in selected fescue cultivars. Collaboration with Swalof Weibull seed company in Sweden is leading to the selection and breeding of highly weed suppressive fescue cultivars for landscape uses.