Identification Guide for Weeds in Cranberries

Identi cation Guide for

Weeds in

Cranberries

Identification Guide for

Weeds in Cranberries Translated and edited by Hilary Sandler, Extension Assistant Professor, Weeds/IPM, University of Massachusetts-Amherst Cranberry Station, Project Leader Leo Dalbec, Translator/Cranberry Grower, Rochester, MA Katherine Ghantous, Research Associate, Weeds/IPM, University of Massachusetts-Amherst Cranberry Station

From Guide d’identification des mauvaises herbes de la canneberge published in 2013 (ISBN 978-2-7649-0246-2) created by Romain Néron, agronomist-botanist, ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec (MAPAQ), Jean-Pierre Deland, agronomist, Club environnemental et technique atocas Québec (CETAQ), Isabelle Drolet, agronomist (CETAQ), and Jacques Painchaud, agronomist (MAPAQ) In collaboration with Sam Chauvette, agronomist, Centre d'expertise et de transfert en agriculture biologique et de proximité (CETAB)

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Warnings At the time of original French publication (2013), the informational content of the guide was found to be representative of cranberry production in the Province of Quebec.

During the translation process, we realized weed species important to production areas outside of Quebec should be included in the English version.

To address regional differences regarding the representation of problematic weeds, input was solicited from weed scientists throughout the English-speaking cranberry production areas to determine the weeds to be added in the English translation version; species inclusion was decided by consensus. The priority ratings are related mostly to our experience in the Northeast but priority rating information provided by weed specialists throughout the Englishspeaking production areas is included.

Any use of this guide becomes the exclusive responsibility of the reader.

It is expressly prohibited to reproduce, print, translate or otherwise adapt this document, in its entirety, or in any part, in any format and by any process whatsoever, including photocopying and referencing, without the previous written authorization of the Centre de référence en agriculture et agroalimentaire du Québec (CRAAQ).

For additional information and comments: Centre de référence en agriculture et agroalimentaire du Québec (CRAAQ) Édifice Delta 1, 2875, boulevard Laurier, 9e étage, Québec (Québec) G1V 2M2 418 523-5411 | 1 888 535-2537 | www.craaq.qc.ca | client@craaq.qc.ca

© Centre de référence en agriculture et agroalimentaire du Québec, 2015 PPTF0117-PDF ISBN 978-2-7649-0490-9 ISBN 978-2-7649-0489-3 (printed document)

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The Center for Agriculture, Food and the Environment at the University of Massachusetts Amherst integrates research and outreach education in agriculture, food systems and the environment. UMass Extension, the Massachusetts Agricultural Experiment Station and the Water Resources Research Center are the units of the Center.

Pursuant of the Mission of the U.S. Cooperative Extension Service to provide farmers with information from agricultural research and to encourage adoption of improved farming methods, the Center supports University faculty and staff in conducting programs of integrated research and educational outreach that impact agriculture, food systems, environmental well-being and human health.

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Scientific review Review of the weeds published in the French guide Michelle Garneau, botanist, Herbier Louis-Marie, Université Laval Caroline Turcotte, agronomist, Direction régionale de l’Estrie, MAPAQ Additional botanical information for the English translation was provided by the editors and reviewed by: Carolyn DeMoranville, Extension Associate Professor, University of Massachusetts-Amherst Cranberry Station

Graphics and layout Jérôme Harrisson-Gauvin, jeromehg.com Nathalie Nadeau, graphic designer, CRAAQ

Primary photographic credits Photographer: Romain Néron, MAPAQ Alternate photographers:

John Beetham: 221D Sam Chauvette: 8, 20C, 20E, 21H, 21I, 25C, 27I, 28A, 28B, 31F, 37H, 42D, 49E, 49F, 50A, 50C, 58A, 58B, 58E, 62D, 65K, 66E, 67A, 68B, 68D, 75A, 75B, 75C, 75D, 75E, 80F, 80G, 82A, 82B, 82C, 82D, 83D, 84D, 85C, 88B, 89I, 91D, 95B, 95C, 95D, 96C, 96D, 97I, 100A, 101I, 105I, 106D, 112C, 122D, 126A, 127F, 127G, 128A, 128B, 135A, 135C, 135D, 139A, 143A, 146A, 149F, 149H, 159J, 175 H, 188H, 201K, 203F, 203J, 206C, 208H, 209B, 209C, 209D, 208I, 212A, 212B, 212C, 212D, 217E, 229A, 229B, 229D, 236C, 236D, 237A, 243A, 243E, 243F, 251C, 252E, 252F, 252G, 252H, 255H, 258A, 258B, 258C, 258E Jed Colquhoun: 69A, 70C, 76A Jennifer Cote: 60G, 92B, 93C, 116D, 117F, 129B, 147B, 147C, 147D, 184E, 184F, 239A, 250A, 250C, 250D Wendy Cutler: 147E Normand Dignard: 136E, 136F, 136G, 136H, 136I, 138E, 138F, 138G, 138H, 138I, 138J, 140G, 143B, 143G, 159F, 159G, 159H, 159I, 161E, 161F, 161G, 161H, 161I, 161J, 161K, 163E, 163F, 163G, 163H, 163I Joe DiTomaso: 232E Jacqueline Donnelly: 32F Isabelle Drolet: 6, 7, 9 Peter Dziuk: 146C Pierre-Patrick Fillion: 144B, 240A, 240C, 250F

· vi ·

Jim Fowler: 238C Katherine Ghantous: 32A, 32C, 32D, 45A, 45B, 45C, 61B, 61C, 153N, 153O, 153P, 190A, 190B, 190C, 191E, 191F, 221A, 241A, 241B, 241C, 242D, 242E Nuuuuuuuuuuul: 93D Mary Keim: 238B Seig Kopinitz: 221B, 221C Matt Levin: 93E, 191G Joshua Mayer: 45D Glen Mittelhauser: 227D Dean Morley: 130D, 130E Joe Neal: 181B Hugh and Carol Nourse: 32B Thomas Palmer: 76B, 77C, 77D Jean Pawek: 146D Robert Perry: 92A Bob Peterson: 32E Randall Prostak: 181D, 182E, 182F Harry Rose: 33A, 33B, 33C, 33D, 33E, 33F, 61A, 69B, 70D, 70E, 116B, 116C, 117G, 183B, 190D Hilary Sandler: 247A, 247B, 247D, 248E, 248F, 248G, 249H Dan Schiffhauer: 238A, 238D John Tann: 61D, 61E Fabrice Verrier: 129C

Acknowledgements For their contribution to the French guide: France Allard, technician, CETAQ Claire Fecteau, technician, Herbier du Québec, Institut de recherche et de développement en agroenvironnement (IRDA) Kathleen Thibodeau, coordinator activities and communications, Association des producteurs de canneberges du Québec (APCQ)

· vii ·

The Editors of the translated guide greatly appreciate the input of the following individuals: Charles Armstrong, University of Maine Sam Chauvette, Centre d’expertise et de transfert en agriculture biologique et de proximité (CETAB) Jed Colquhoun, University of Wisconsin-Madison Jennifer Cote, University of Maine Jean-Pierre DeLand, Ocean Spray Cranberries, Inc. Graham Gavin, New Brunswick Department of Agriculture, Aquaculture and Fisheries Bradley Majek, Rutgers University Brian Mauza, Ocean Spray of Canada, Ltd. Romain Néron, ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec (MAPAQ) Kim Patten, Washington State University Robert Perry, University of Wisconsin-Madison Erika Saalau-Rojas, University of Massachusetts-Amherst Cranberry Station David Yarborough, University of Maine

The French guide Guide d’identification des mauvaises herbes de la canneberge was made possible with the support of the ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec and the financial grant of the Programme de soutien au développement de l’agriculture biologique.

· viii ·

The translation of Guide d’identification des mauvaises herbes de la canneberge and publication of this guide was supported, in part, with funding from the Northeastern IPM Center (NortheastIPM.org) and the generous donations of the American Cranberry Growers Association, British Columbia Cranberry Marketing Commission, Massachusetts Cranberry Research Foundation, New Brunswick Department of Agriculture, Aquaculture and Fisheries, Newfoundland Labrador Department of Natural Resources, Nova Scotia Department of Agriculture, Prince Edward Island Department of Agriculture and Forestry, and University of Massachusetts Extension.

This book is dedicated to my parents, Morton and Frances Sandler, who gifted to me an inheritance to love deeply and gratefully, to be honest in all matters, and to show grace to those whom I meet in life's journey.

Hilary Sandler

Preface

The first step in obtaining good weed management is correct identification.

After viewing the excellent cranberry weed identification guide produced for French-speaking cranberry growers, many English-speaking cranberry growers, scientists, and industry personnel voiced their desire to make a similar guide available in English. Financial support was sought and obtained to translate the French identification guide for weeds into English and to support its publication. The English guide is the translated version of the excellent scientific collaboration represented in the French guide. Additional botanical information for the original weed descriptions was added as seen fit by the editors. A new category in the botanical description, describing differences between similar species, was also added.

Weed scientists representing the various English-speaking cranberry production areas discussed (via conference calls and e-mails) the possible inclusion of more weed species and decided to add 24 weeds that were not included in the French version. Botanical information for the new weeds was gathered and vetted by the editors. We hope the addition of these weeds will improve the utility of the guide for the English-speaking audience of cranberry growers and other interested parties.

The weed species added to the English version (not present in the French guide) are: Andropogon virginicus, Broomsedge bluestem

Maianthemum canadense, Canada mayflower

Cardamine hirsuta, Hairy bittercress

Melilotus officinalis, Sweetclover

Clethra alnifolia, Coastal sweetpepperbush

Panicum dichotomiflorum, Fall panicgrass

Cyperus dentatus, Toothed flatsedge

Photinia melanocarpa, Black chokeberry

Danthonia spicata, Poverty oatgrass

Pteridium aquilinum, Western brackenfern

Hieracium aurantiacum, Orange hawkweed

Rumex crispus, Curly dock

Hypericum boreale, Northern St. Johnswort

Sagittaria latifolia, Broadleaf arrowhead

Hypericum gentianoides, Orangegrass

Schoenoplectus americanus, Chairmaker’s bulrush

Hypochaeris radicata, Hairy cat’s ear

Setaria pumila, Yellow foxtail

Kalmia angustifolia, Sheep laurel

Sisyrinchium spp., Blue-eyed grass

Lachnanthes caroliniana, Carolina redroot

Smilax glauca, Cat greenbrier

Linaria vulgaris, Butter and eggs

Vicia sativa, Garden vetch

The Priority Rating for the weeds in the French guide was reviewed and minor adjustments were made to represent our experience in Northeastern cranberry production. Due to the variation of weed growth, impact, and control across the English-speaking regions, it was logistically difficult to have priority ratings relevant for all regions. Readers are encouraged to write in their own assessments directly in the guide to improve its utility.

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· xiii ·

The text in the French guide (especially the initial portions) was heavily oriented towards organic methods as many of Quebec growers grow organic fruit. In fact, the Province of Quebec is the principal region for the production of organic cranberries in the world. In 2012, 15% of all cranberry acres in Quebec were organically grown. We have included some of the original text but have geared it more towards an integrated weed management (IWM) approach and de-emphasized organic production. Some of the cultural or mechanical methods mentioned may control weeds on their own or within the context of an IWM plan. Specific herbicide recommendations have been purposefully omitted as these can change over time and can vary significantly by region. Please contact an Extension Specialist or other knowledgeable expert in your area for chemical and IWM advice.

Although the French guide was directed solely to cranberry growers, our advisory group consisted of experts who could provide direction about weed problems for both cranberry and their close relative, low-bush blueberry.

Thus, this guide should be of value to both cranberry and low-bush blueberry growers for weed identification.

· xiv ·

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Table of contents

Introduction xiii Preface 1

Weeds as they relate to cranberry production

2

Plant classifications

4

Weed management in cranberry production

10

How to use this guide

Annual broadleaf herbaceous plants 15

Characteristics of Broadleaf Plants (Dicots)

31

18

Annual ragweed

20

Nodding beggartick

33 Garden vetch

22

Devil's beggartick

23

American burnweed

25

Marsh cudweed

26

Jewelweed

28

Corn spurry

30

Lambsquarters

Oakleaf goosefoot

32 Orangegrass 34

Green carpetweed

36

Marshpepper knotweed

38

Curlytop knotweed

39

Spotted ladysthumb

40

Arrowleaf tearthumb

42

Green smartweed

Biennial or perennial broadleaf herbaceous plants

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45

Broadleaf arrowhead

72

Indian tobacco

46

Spreading dogbane

73

Red sandspurry

47

Bristly sarsaparilla

75

Grass-like starwort

49

Common milkweed

76

Northern St. Johnswort

50

Common yarrow

51

Western pearly everlasting

78

Lesser Canadian St. Johnswort

52

White panicle aster

79

Pale St. Johnswort

54

Parasol whitetop

82

Large St. Johnswort

55

Canadian horseweed

83

Dwarf St. Johnswort

57

Common boneset

84

Common St. Johnswort

58

Spotted joe pye weed

59

Orange hawkweed

85

Fraser's marsh St. Johnswort

61

Hairy cat's ear

88

Hedge false bindweed

62

Fall dandelion

90

Ditch stonecrop

63

Flat-top goldentop

91

Bird's-foot trefoil

66

Canada goldenrod

92

Sweetclover

67

Common dandelion

94

Golden clover

68

Coltsfoot

95

White clover

69

Hairy bittercress

96

Bird vetch

71

Bog yellowcress

98

American water horehound

100 Northern bugleweed · xv ·

102 Purple loosestrife

120 Virginia strawberry

104 Fireweed

121 Silverweed cinquefoil

106 Fringed willowherb

122 Norwegian cinquefoil

108 Bog willowherb

123 Common cinquefoil

110 Little evening primrose

125 Canadian burnet

111 Common yellow oxalis

126 Common marsh bedstraw

112 Common plantain

128 Canada toadflax

113 Common sheep sorrel

129 Butter and eggs

116 Curly dock

131 Bog white violet

118 Earth loosestrife Woody and suffrutescent plants 135 Red maple

154 American red raspberry

137 Paper birch

155 White meadowsweet

139 Grey birch

157 Steeplebush

141 Coastal sweetpepperbush

158 Balsam poplar

143 Leatherleaf

160 Eastern cottonwood

144 Sheep laurel

162 Quaking aspen

146 Bog laurel

164 Bebb willow

147 Black chokeberry

166 Pussy willow

148 Allegheny blackberry

167 Balsam willow

151 Bristly dewberry Grasses, sedges, rushes, and other monocots 171 Characteristics of Monocots

199 Rice cutgrass

Annual grasses

202 Wirestem muhly

174 Smooth crabgrass

205 Western panicgrass

176 Hairy crabgrass

206 Common reed

177 Barnyardgrass

209 Annual bluegrass

179 Witchgrass

210 Fowl bluegrass

181 Fall panicgrass

211 Kentucky bluegrass

183 Yellow foxtail

Carex spp.

Perennial grasses

212 Silvery sedge

185 Redtop

213 Creeping sedge

187 Rough bentgrass

215 Crawford's sedge

190 Broomsedge bluestem

216 Fewseed sedge

192 Bluejoint

219 Broom sedge

194 Poverty oatgrass

220 Little green sedge

195 Quackgrass 197 Rattlesnake mannagrass · xvi ·

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Scirpus spp.

233 Toad rush

221 Chairmaker's bulrush

234 Common rush

222 Blackgirdle bulrush

236 Thread rush

223 Woolgrass

237 Poverty rush

225 Panicled bulrush

Other monocots

Other sedges

238 Carolina redroot

226 Toothed flatsedge

239 Blue-eyed grass

228 Strawcolored flatsedge

240 Canada mayflower

230 Tussock cottongrass

241 Cat greenbrier

Juncus spp.

243 Broadleaf cattail

231 Narrowpanicle rush Miscellaneous plants 247 Dodder 250 Western brackenfern 251 Sensitive fern 254 Field horsetail 256 Liverwort 258 Polytrichum moss 259 Sphagnum Conclusion 261 Appendix 1: Priority Ratings 273 Resources 275 Glossary 279 Features Key 287 Index of common names 291 Index of Latin names

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· xvii ·

Weeds as they relate to cranberry production A weed is defined as a plant growing in a place where it is not wanted. Many plants can be considered weeds, however, the most damaging weeds are those that are best adapted to the growing requirements of a particular crop.

Managing weeds in a perennial crop that has continuous canopy across the production area (like cranberry) is especially challenging. Cranberry weed management is particularly constrained because many of the weed management tools available in annual crops (rotation, hoeing, etc.) cannot be used.

The presence of weeds in cranberry is a management issue for every grower.

Weeds compete with cranberries for water, sunlight, space, and nutrients.

Some weeds provide habitat for beneficial insects and pollinators, while others may provide refuge for harmful pests. Furthermore, certain weeds can impede harvest operations. Significant overall losses can occur due to unmanaged weed infestations.

Effective weed management begins with the accurate identification of problematic plants. Identification allows for prioritization of the weeds present and assists in making judicious decisions regarding methods of control. Furthermore, improved weed identification promotes better understanding of weed biology and habitat, leading to the inclusion of proactive weed management measures.

Integrated Weed Management (IWM) includes the use of all available tactics to manage weeds within an agricultural system. It is a decision-support system for the selection and use of weed control strategies, either singly or in combination, to achieve a desirable level of control. According to Zimdahl (2007), a good weed management tool box includes the following seven logical steps: prevention, mapping, prioritization, development of an IWM system, implementation of systematic management, record keeping and evaluation, and persistence.

As with any plant, weeds require certain elements to successfully complete their establishment, growth, and reproduction. The appearance of new weed species on a bog can be a symptom of changing soil or water conditions.

For example, growth of rushes may indicate poor drainage, the appearance of moss suggests excess water, and the presence of plantains may point to soil compaction, etc. The remediation of sub-optimal conditions should be the first step in managing weeds. In addition, corrective actions should improve the cranberry plants’ competitive advantage over the weeds.

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· 1 ·

Plant classifications

Plant species are classified by their mode of reproduction and their lifecycle.

Some reproduce with seeds (flowering plants) or by spores (non-flowering plants). Seed-producing plants are divided into two broad groups based on the number of seed leaves and general leaf shape: narrow-leaved plants or monocots (monocotyledons) and broad-leaved plants or dicots (dicotyledons). Plants are annuals, biennials, or perennials. Perennials are either herbaceous or woody plants.

Seed are the structures that contain and protect embryos. They are the structures formed by the growth of the ovule (female egg) after fertilization. Seed contain the necessary reserves to support the development of the germinating plant. Seed allow for the dissemination of the plant.

Spores are reproductive cells that can generate another plant without fusion with another cell. Spores are generally unicellular and resemble dust. Ferns, horsetail, and mosses are spore-producing plants.

Monocots are flowering plants that initially produce a single cotyledon (one seed leaf). Monocots typically have long, narrow leaves with veins that run more or less parallel with each other. Monocots include grasses, sedges, and rushes. Some plants (e.g., Smilax, Lachnanthes) may not appear to fit the typical description (e.g., Smilax, Lachnanthes) but still fall under this classification.

Dicots are flowering plants that initially produce two cotyledons (two seed leaves). Dicots are characterized generally by large leaves with their veins appearing in a network pattern rather than running parallel as with monocots.

Dicots may be woody or herbaceous plants. Herbaceous plants have leaves and stems that die down at the end of the growing season to the soil level; they have no persistent stem above ground. They can have annual, biennial or perennial life cycles. Woody plants produce wood as a structural tissue and are perennial. These are usually trees or shrubs with woody stems that persist for several to many years.

Suffrutescent plants have herbaceous and woody traits. They are slightly or mostly woody at the base and have herbaceous stems at the tips. They differ from other herbaceous perennials in that they do not die back each year and have stems and other plant parts that persist for many years.

LIFECYCLES Annual plants complete their lifecycle (germination, flowering, seed production and death) in a single year. Annual plants generally germinate in the spring and produce seed during summer or fall of the same year. The plant dies after seed production. In some cases, a given plant will complete its life cycle over the course of more than one year; this plant is referred to as an over-wintering annual. In this case, the seed that germinates late in the season produces a rosette of leaves or a vegetative shoot that survives the winter and regrows the following season to flower and to complete its lifecycle.

Annual plants reproduce exclusively by seed. They can produce large quantities of seed enhancing their dispersal potential. Seed may remain viable in the soil for years and will germinate when conditions become favorable.

Annual weeds in cranberry bogs require loose crumbly soil, high levels of nutrients, and light for germination and growth. Annual weeds can be problematic especially on new bogs and on thinly vined portions of established bogs. If not managed effectively, they will grow rapidly and hinder vine colonization of the ground, which will negatively impact fruit production in future

· 2 ·

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years. Annual plants are not generally problematic weeds in well-established cranberry bogs.

Biennial plants complete their lifecycle (germination, flowering, seed production and death) over two years. Seed germinate in the spring, produce a rosette of leaves and remain in a vegetative state during the first summer.

Overwintering as rosettes, they flower and produce seed the following season.

The plant dies at the end of the second growing season. As with annual plants, biennial plants reproduce exclusively by producing large numbers of seeds.

Perennial plants develop and flower over the course of several years. The plants produce vegetative structures that can produce new plants as well as seed. Many types of plants are in this group: clustering plants (producing suckers), rhizomatous plants (producing horizontal underground stems), and stoloniferous plants (producing horizontal runners on the soil surface).

New plants can even be produced by small pieces of rhizomes, stolons, and stems. Some perennial plants produce tubers and bulbs, which separate from the mother plant and provide another means of spreading and propagating.

Perennial plants use several modes of propagation.

Perennial weeds are the majority of weeds found on established cranberry bogs. The vegetative expansion of perennials may be slow following germination, but certain species, especially well-adapted to the growth conditions of cranberries, have the ability to quickly colonize and outcompete cranberries.

Weeds and seed may be disseminated by contaminated cuttings, water, humans and their activities, wind, and animals.

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· 3 ·

Weed management in cranberry production CRANBERRY CHARACTERISTICS Cranberry is in the Heath family, Ericaceae (the same family as blueberry) and grows in acidic soils where the optimal pH is maintained between 4.0 and 5.0.

Morphologically, cranberry has two distinct parts: the stolons (runners) that promote vegetative propagation of the plant, and vertical stems (uprights) that support flowers and fruit. Native varieties (e.g., Howes, Early Black) tend to bear biennially (i.e., a portion of uprights alternate between vegetative and fruit-bearing years). Newer hybrids (e.g., Mullica Queen, Crimson Queen) are less likely to exhibit biennial bearing and can reliably produce equivalent crops year after year.

Cranberry plants usually require several years to colonize the production surface. Generally, the production potential of cranberry plants is not reached until the fifth year after planting. During these early growth years, the open spaces between cranberry plants are often colonized by weeds, especially annuals. During the latter part of the establishment phase, weed infestations by perennials become more common.

PREVENTIVE METHODS Preventive methods can be used by cranberry growers to minimize the establishment of weeds. Known methods that are currently recommended are discussed first; two methods needing further evaluation are discussed last.

Use clean materials in cranberry bog construction Use weed-free material when selecting, handling and transporting materials for bog construction. During new bog construction, consider removal of 6 to 12" (15 to 30 cm) of the existing substrate to eliminate any present vegetation along with a majority of seed, rhizomes, stolons, and tubers. If sand is to be added to the substrate, it is preferable to use sand that has been deeply excavated as opposed to surface sand that might contain weed seed or pieces.

Optimize drainage The irrigation and drainage system, including heads, nozzles, drains, flumes and ditches should be optimized. Many weeds in cranberry prefer wet environments. An effective drainage system will assure cranberry vigor and its competitiveness with weeds.

Manage irrigation at planting time As the cranberry roots develop, the frequency of irrigation should be gradually reduced to maximize root extension. With this practice, the surface remains drier, making it more difficult for weed seed to germinate.

Manage harvest water; remove debris and trash Many weed seeds can be transported by flood waters at harvest time. Where harvest water is moved from one bog to another, it is preferable, where possible, to start harvesting in areas with the least amount of weed infestation, finishing with those bogs with greater weed infestation. This practice will reduce the amount of weed seed that is carried from one bog to another.

The removal of floating debris during and after the harvest removes weed seed. Dispose of leaf litter at least 0.25 miles (400 m) from a bog, since trash piles may become an inadvertent source of weed infestation for seed that are carried by the wind. · 4 ·

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Acidify soil with sulfur Cranberries compete better for nutrients in an acid soil (pH 4 to 5). Maintaining the pH at a level that favors cranberries may discourage the growth of some undesirable species.

Select appropriate species and maintain perimeters Choose low-risk species for windbreaks, avoiding poplars, willows, and birches. Dikes and edges of canals and reservoirs should be planted with species that do not present a risk of infestation on the bogs. Dikes, canal edges, and the edges of reservoirs should be mowed at least twice per growing season before seed formation.

Clean and maintain equipment Properly clean any equipment used on a bog infested with weeds to remove seed, plant fragments, rhizomes, and runners, thereby preventing the inadvertent contamination of non-infested bogs.

Use adequate planting densities Use a high density of cuttings at planting time, followed by practices that promote rapid colonization by cranberry plants, to minimize competition by weeds.

Use weed-free cuttings and clean sand Obtain cuttings from a bog without weed infestations. Before buying, visit the bog from which cuttings are to be harvested. Use sand known to be free of seed and weed fragments.

Maintain a vigorous cranberry plant canopy Well-maintained cranberry bogs will hinder weed emergence, infestation and growth. Fertilize properly and scout for pests. Maintain proper irrigation schedules. Soil compaction negatively impacts cranberry health and encourages the invasion of certain weed species. Replant damaged areas quickly to prevent the establishment of weeds.

Use of in vitro plants for propagation

In vitro (“in glass”; outside the normal biological context) cultivation, which has allowed for the production of new plants free of contamination, has been utilized in Newfoundland. The costs of production of in vitro plants and those in plugs are significantly higher than traditional cuttings.

Clean cuttings prior to planting new bogs No method of cleaning cuttings suspected of contamination by seed and weed fragments is available or under development. This capability would reduce the introduction of weeds at planting time.

WEED MAPPING AND PRIORITIZATION Weed mapping is essential for the implementation of any credible approach to weed management. Weed mapping gives a pictorial or graphical display of weed species present and their levels of infestation. A schematic identifies localized infestations on a bog. Weed-mapping technology can easily be adapted to the grower’s specific needs. Minimally, this technology could be used to track weed species with the highest potential to become problematic.

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· 5 ·

Weed prioritization can reflect a grower’s particular weed problems and weed management program. Use of a rating scale can be helpful in determining weed management priorities.

The Priority Rating of each weed species was determined by considering the four criteria listed below. For each weed, a score of 8, 4, 2, or 1 was assigned to each criterion. The total number of points determined the priority rating for the given weed: Low = 4 to 7 points; Medium = 8 to 15 points; High = 16 to 23 points; Very High = 24 to 32 points (see Appendix 1, pp. 261 - 272).

The criteria used to determine the priority rating of a given weed species are the following: •• Impact of a given weed on the cranberry plants themselves: 8 = killing or significantly crowding out cranberry plants; 4 = reducing vine vigor; 2 = reducing yield; 1 = little effect.

•• Biological form or type of a given weed: 8 = perennial plant similar to the cranberry in growth pattern, having extensive systems of rhizomes and/or stolons; 4 = perennial plant different than that of a cranberry, producing rhizomes or stolons; 2 = perennial or biennial plant, producing shoots (suckers) or producing few rhizomes or stolons; 1 = annual plant.

•• Invasive/reproductive capacity of a given weed: 8 = very vigorous production of stolons and rhizomes, propagation via plant parts, bulbs, seed; 4 = low to moderate production of stolons and rhizomes, some propagation via plant parts, by seed; 2 = propagation by seed only, with high seed production; 1 = propagation by seed only, with few seed produced.

•• Adaptation to typical cranberry habitat of a given weed: 8 = well-adapted to typical bog conditions, difficult to pull; 4 = well-adapted, easy to pull; 2 = marginally adapted, difficult to pull; 1 = marginally adapted, easy to pull.

•• This methodology has been adapted from the priority charts developed in Massachusetts (Else et al. 1995; Sandler and Ghantous, 2015).

CULTURAL AND MECHANICAL WEED CONTROL OPTIONS Given that the cranberry is a perennial plant that ultimately covers a bog surface in a continuous canopy, crop rotation for weed control and the use of physical weed barriers such as plastic or straw, or green manure are simply not realistic. Cultural weed control methods that can be used in both conventional and organic production systems are discussed below. Two untested methods meriting further evaluation are discussed last.

Hand-weeding Hand-weeding is the principal method of cultural weed control. It is effective against annual weeds if done prior to seed formation. For perennial weeds, it is important to remove as much rhizome, tuber, etc., biomass as possible. Removal is easier when the soil is moist. Weed removal is easier when weeds are small. For woody plants, such as · 6 ·

Hand-weeding on new plantings

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small trees, growers use different types of tools (such as pliers or a weed wrench) that allow the removal of stems and roots.

For woody plants, it is important to remove stems and roots

Hand-weeding later in the season

Mowing prior to seed formation On new plantings, mowing and mechanical removal of weeds that extend above young cranberry plants appears to work well. Mow prior to seed formation. The mowing of weed stems at this early stage stimulates the plant to use stored reserves to produce new growth; eventually its ability to overwinter and survive will be reduced. Mowing reduces problems with mechanical harvesters and thus reduces damage to cranberry fruit. Destroy all removed plant parts.

Mowing and mechanical removal of weeds above young cranberry plants

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· 7 ·

Sanding and mowing An application of sand every 3 to 4 years stimulates cranberry vigor and may arrest the development of certain weed seed (annual grasses) and dodder.

On recently planted bogs with significant weed infestations, a combination of mowing weeds, as described above, along with winter ice sanding, can reduce the impact of certain weed species. A consecutive series of such treatments favors cranberry plants and weakens weeds.

Sanding in winter

Thermal treatment using hand-held torches Several types of torches (open-flame and infrared) have been tested to treat aggressive weeds in organic cranberry production, such as brambles (Rubus spp.) and rushes (Juncus spp.). Both torches had some impact on rushes when the exposure was extended (6 to 9 seconds with open-flamed torches), but had less of an effect on Rubus spp. When considering cost factors in the evaluation, open-flamed torches appeared to be most cost-effective. The cost of localized treatment with herbicides in conventional cranberry production compares with that of the open flame torch (Ghantous et al., 2012, 2013).

Spot treatment with vinegar Experimental efforts have demonstrated the efficiency of horticultural vinegar (10 to 20%) to manage certain perennial weeds. Injections (special tool needed) made into the soil at the point where the weed plant emerges have given good results. Vinegar has efficiency against perennial weeds having suckers and compact tufts (e.g., grasses, rushes and sedges). Efficacy is reduced for plants having long rhizomes and stolons. Each grower should consult with local specialists on the approval status of this product.

Flooding Short- and long-term floods can be used for weed management (Sandler and Ghantous, 2015). Short, late-spring floods, targeting newly emerged dodder seedlings, can be effective in some situations (O'Connell et al. 2011). Summer floods (held for 60 days) can suppress or kill dewberry (Rubus spp.) but can also injure cranberry vines; crop is lost in the year of the flood. Fall floods (usually 2 to 3 weeks long) can also suppress dewberry populations (DeMoranville et al. 2005). The use of late water floods (a 30-day reflood starting mid-April) may delay weed emergence or suppress growth of some

· 8 ·

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weeds. The practicality and efficacy of using flooding for weed management should be evaluated prior to use. Flooding could cause vine stress or injury if not used correctly and may exacerbate vine stress when used in combination with other cultural practices (e.g., sanding). It is recommended to consult with an knowledgeable and experienced person prior to using flooding for weed management.

Spot treatment with hot water Spot treatments with hot water were first used during the 2010 growing season (in Quebec). This technique consists of injecting water approaching the boiling point near the roots of weeds. Further efforts are warranted to better evaluate the efficacy of this technique on different weed species.

Injecting hot water near the roots of weeds

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· 9 ·

How to use this guide

OVERALL ORGANIZATION The described weeds are classified in several groups based on their morphological characteristics.

•• Basic weed management information (maroon) •• Annual broadleaf herbaceous plants (light green) •• Biennial and perennial broadleaf herbaceous plants (dark green) •• Woody and suffrutescent plants (blue) •• Monocots: annual grasses, perennial grasses, sedges, rushes, and other monocots (orange) •• Miscellaneous plants (purple) •• Priority ratings, resources, glossary, features key, and indexes (maroon) FORMAT FOR WEED SPECIES PRESENTED IN THIS GUIDE For each species, the following information is presented: Identification: Primary common name, other common names (if appropriate), Latin name and botanical family are listed at the top of the first page for each weed species. The USDA PLANTS Database (http://plants.usda.gov) was used as the authority for common name(s), Latin name(s), and botanical family.

Priority rating (top margin):

n low

nn medium nnn high

nnnn very high

Plant Status by state, region, or province: Using the USDA PLANTS Database as the authority, information of reported (or not) occurrence of a species is listed by state or province. A plant is listed as native, introduced, both native and introduced, or not reported. Although a plant may be listed as occurring in a state or province, the plant may or may not be a cranberry weed. When generalizations are made regarding the plant status for a collective group of states (e.g., the Northeast), provinces, or regions, the information is only related to the cranberry growing states or provinces listed below.

The following abbreviations were used: MA Massachusetts

ATL Atlantic Provinces (as a group)

ME Maine

BC British Columbia

MI Michigan

NB New Brunswick

NJ New Jersey

NL Newfoundland

NY New York

NS Nova Scotia

RI Rhode Island

PEI Prince Edward Island

OR Oregon

QC Quebec

WA Washington WI Wisconsin

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Botanical description: the characteristics of leaves, stems, flowers, fruit, seed, and method of dispersal are listed. The number of flower parts are mentioned parenthetically, when known, using Newcomb’s Wildflower Guide as the authority. Measurements (greater than 5 mm) are presented in both English and metric units. Supplementary information is presented under subheadings, “Distinctive features” and “Note”.

Favorable growing conditions: characteristics of an environment favoring growth of a weed.

Prevention and suppression: proactive cultural or mechanical measures to minimize the impact of a weed.

Similar species: if appropriate, similar species are mentioned, highlighting differences with the described weed.

HOW TO MAKE ACCURATE PLANT IDENTIFICATIONS Pay particular attention to the arrangement and shape of the leaves, to the characteristics of the stem, flowers, and fruit, if necessary. One must also consider the general appearance of a plant. In some cases, the observation of stolons or rhizomes may help to correctly identify a plant. Locate individuals with good identifying parts still attached (generally weeds with flowers). In other cases, especially where young plants are concerned, look for mother plants (even if withered) to assist with proper identification.

If collecting a specimen for someone else to identify, collect at least 10 whole individuals (roots, stolons, stems, leaves, flowers, etc.). Keep the plants cool (perhaps wrapped in a barely wet paper towel), especially if there may be a long time between collection and identification. Write down where the plants were found and the date collected.

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· 11 ·

Annual Broadleaf Herbaceous Plants

· 13 ·

n

Annual ragweed Ambrosia artemisiifolia Asteraceae

B

A

D

C

E

F

A. Plant on a bog. B. Cluster of male flowers. C. Female flowers in leaf axil.

D. Compound leaf. E. Stem. F. Base of plant and root system.

Both native and introduced in U.S. states; native for Canada. Annual plant. Blooms in summer-fall.

Botanical description: leaves are simple, opposite (usually towards the base) or alternate, irregularly toothed and deeply lobed. Leaves can be once or twice compound. Older leaves tend to be hairless; younger leaves usually have hairy undersides. Upright, hairy, branching stems are 8 to 40" (20 to 100 cm) tall. Male flowers (parts indistinguishable) are yellow to greenish and grouped in clusters (racemes) at the top of the stem and the tips of the branches; female flowers (parts indistinguishable) are greenish, inconspicuous and located in the leaf axils. Distinctive features: seed have extended longevity in the soil. Note: ragweed pollen is a significant allergen in late summer.

Favorable growing conditions: grows well in moist and clay-type soils where the pH is between 6 and 7. It grows well in locations with direct sunlight.

Prevention and suppression: hand-weed plants prior to seed formation.

Clean bog edges. Maintain a healthy canopy of cranberry vines. Keep soil pH low. · 18 ·

Annual Broadleaf Herbaceous Plants

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H

I

G

J

K

L

G. Mature plant. H. Young plant. I. Seedling with 4 leaves, opposite.

J. Seedling with 2 leaves, with first leaves rounded. K. Plants, top view. L. Infestation.

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Annual Broadleaf Herbaceous Plants

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Nodding beggartick Bidens cernua Asteraceae

A

D

B

C

E

A. Plants in the field. B. Hairs on stem and base of leaves. C. Leaf.

D. Flowers. E. Opposite leaves.

Native to all regions; not reported in NL. Annual plant. Blooms in summer.

Botanical description: opposite, simple, long leaves (1.5 to 8"; 4 to 20 cm) have toothed margins; leaves are sessile (no petiole). Upright stems are 12 to 30" (30 to 80 cm) tall, often reddish, and covered with long rigid hairs. Yellow flowers (parts indistinguishable) with a brownish yellow center, are 1.5 to 2" (4 to 5 cm) in diameter, usually with 8 petals (sometimes without petals); green narrow leaf-like bracts are beneath flowers. First leaves (cotyledons) are long. Distinctive features: at maturity, flower clusters are droopy or nodding.

Favorable growing conditions: well-adapted to moist environments.

They are often found in ditches along fields. This plant will colonize different soil types including organic soil.

Prevention and suppression: prevent seed formation and hand-weed young plants. Keep bog edges and irrigation canals clean.

· 20 ·

Annual Broadleaf Herbaceous Plants

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