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Project Leader(s): 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; Agnes Rimando, natural products chemist,
USDA National Center for Natural Products, Oxford MS.
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 Cornell’s 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 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. Longterm 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.
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