46. Grasses and Sedges - Syndicat des producteurs de bleuets du

Wild Blueberry
Production Guide...
in a Context of
Sustainable Development
46. Grasses and Sedges
Latin names: Graminaceae sp. et Carex sp.
French names: Les graminées et les carex
The Carex genus accounts for some 200 different species of sedge in Québec. As for the family of Graminaceae (grasses), it
includes nearly 600 genera and more than 6500 species distributed through every latitude and habitat. These plants are
therefore widely spread throughout the Québec landscape, and consequently in blueberry fields.
In the Maritime provinces, blueberry fields are often developed from old farm fields. Grasses are abundant due to the land’s
agricultural antecedents and very considerable seed bank. In contrast, Québec blueberry fields are generally developed
from forest stands where jack pine predominate. In that environment grasses are less abundant, and therefore initially
uncommon. Over the years however the incidence of grasses and sedges has become much greater in Québec, especially in
older blueberry fields.
DESCRIPTION
Grasses and sedges are herbaceous plants with certain similarities. They are easily told apart however by examining their
stems. Grasses have cylindrical, hollow stems, while most sedges have triangular, solid stems. Both reproduce by seed, but
some can also multiply by producing new stems from rhizomes.
Grasses
Grasses may be annual or perennial. The inflorescence
consists of spikelets, i.e. small flowers on a spike, at the
base of which are one or two glumes (small bracts that are
distinct from the other leaves accompanying the flower).
Each spikelet starts at the base with two independent and
sterile glumes, followed by fertile glumes containing flowers.
Spikelets are the most common type of inflorescence among
grasses (Figure 1).
Poverty oat-grass (Danthonia spicata), redtop (Agrostis
gigantea), hair bentgrass (Agrostis scabra) and quackgrass
(Agropyron) are just some of the perennial grasses found in
blueberry fields.
Perennial grasses have fibrous root systems. Some species
have rhizomes that produce new shoots, facilitating their
expansion through the field. Perennial grasses that do
not have rhizomes are referred to as “bunch grasses”. Hair
bentgrass is an example of this type of grass. Having neither
rhizomes nor stolons (above-ground prostrate shoots), it
multiplies by the dispersal of its seeds in wind.
Figure 1. Example of grass inflorescence, poverty oat-grass (Danthonia spicata)
Source: Suzanne Hardy, Enracinart
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46. Grasses and Sedges
Sedges
Sedges are for the most part perennial, though in some
species the aerial part dies after a year. They may be
cespitose (growing in clumps) or not. Like some perennial
grasses, they have rhizomes that enable them to propagate
outwards. In some species the rhizomes are very short,
but in others they are long and result in the formation of
extensive thickets of sedge.
While their vegetative part looks like that of grasses,
another distinguishing feature of sedges is the perigynium,
a modified tubular bract that forms a sac around the fruit.
The flowers are borne in spikelets composed in various
ways.
PREVENTION
Though control will not be complete, pruning by burning,
once in every two or three production cycles, will reduce
the dissemination of grass and sedge seed.
CONTROL
No mechanical method, nor any alternative to herbicides,
is currently available for controlling grasses and sedges in
blueberry fields.
Figure 2. Example of sedge (Carex houghtoniana)
Source: Suzanne Hardy, Enracinart
COMPLEMENTARY LEAFLETS
15. Integrated Pest Management in Wild Blueberry Production
19. Pesticides Used in Wild Blueberry Production
REFERENCES
Beaute, T. 2002. Agronomy Guide for Field Crops. Ontario Ministry of Agriculture, Food and Rural Affairs. pp. 158 and 163.
Revised 2009, Publication 811. [Online]. http://www.omafra.gov.on.ca/english/crops/pub811/p811toc.html (Page consulted
on March 17, 2011).
Desjardins, È.-C. and R. Néron. 2010. Guide d’identification des alliés et ennemis du bleuet nain : Insectes, maladies et végétaux.
Centre de recherche Les Buissons. p. 221
Graham, G.L. and M.J. Melanson. 2008. Evaluation of Fluazifop, Mesotrione And Tank Mixes for Grass Weed Control in The
Cropping Year of Wild Blueberries. New Brunswick Department of Agriculture, Aquaculture and Fisheries. 3 pp.
MAPAQ. 2004. Cahier d’autoévaluation de gestion intégrée des ennemis des cultures. Pratiques agroenvironnementales spécifiques,
bleuet nain semi-cultivé. 17 pp.
Marie-Victorin, Frère. 1995. Flore laurentienne. Troisième édition. Les Presses de l’Université de Montréal. p. 700 (sedges) and
p. 757 (grasses).
Yarborough, D. 2001. Postemergence Grass Control for Wild Blueberries. Fact Sheet No. 235. The University of Maine. Cooperative
Extension. [Online].
http://extension.umaine.edu/blueberries/factsheets/weeds/235-postemergence-grass-control-for-wild-blueberries/ (Page consulted
on September 15, 2010).
Wild Blueberry Production Guide
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46. Grasses and Sedges
Yarborough, D. 2001. Cultural Management for Weeds in Wild Blueberries. Fact Sheet No. 252. The University of Maine.
Cooperative Extension. [Online].
http://umaine.edu/blueberries/factsheets/management/cultural-management-for-weeds-in-wild-blueberries/l (Page consulted
on September 15, 2010).
Yarborough, D. 2008. Organic Weed Management in Wild Blueberries. Fact Sheet No. 304. The University of Maine. Cooperative
Extension. [Online]. http://umaine.edu/blueberries/factsheets/organic/304-organic-wild-blueberry-production/ (Page consulted
on September 15, 2010).
PROJECT COORDINATION
PUBLISHING
Sophie Gagnon, Agronomist,
Coordinator, Agrinova, Alma
Project
Management
Chantale Ferland, M.Sc., Publishing Project Officer, CRAAQ,
Québec
Lyne Lauzon, Publications Coordinator, CRAAQ, Québec
ADAPTATION
Sophie Gagnon, Agronomist,
Coordinator, Agrinova, Alma
Project
TRANSLATION
Management
Rod Willmot, M.A.
REVISION
LAYOUT AND GRAPHIC DESIGN
Danielle Bernier, Agronomist-Weed Scientist, Ministère de
l’Agriculture, des Pêcheries et de l’Alimentation du Québec,
Québec
Sylvie Robitaille, Computer Graphics Technician, CRAAQ,
Québec
Gaétan Chiasson, Agronomist, Development Officer, New
Brunswick Department of Agriculture, Aquaculture and
Fisheries, Bathurst
Laurier Tremblay, Agronomist, Ministère de l’Agriculture,
des Pêcheries et de l’Alimentation du Québec, Bergeronnes
PRODUCED BY
FUNDED BY
Association
des producteurs
de bleuets de
la Côte-Nord
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Wild Blueberry Production Guide