BROADLEAF WEEDS of ARABLE CROPS The Ute Guide Trevor James, AgResearch ADDING VALUE TO THE BUSINESS OF ARABLE FARMING
Published by Foundation for Arable Research, PO Box 80, Lincoln 7640, New Zealand. February 2011 ISBN 978-0-9864533-5-9 (Print) 978-0-9864533-6-6 (PDF) Acknowledgements Claire Dowsett, AgResearch, New Zealand for assistance with compiling and sorting the photographs Pauline Hunt, AgResearch, New Zealand for the descriptive drawings Paul Champion, NIWA, New Zealand for critical review and suggestions Copyright Material in this book is copyright to Foundation for Arable Research, excluding photographs which are copyright to Trevor James. No part of this publication may be copied or reproduced in any form without prior written permission of copyright holder.
Preface Farmers often say that managing weeds is their biggest challenge. There is little room for error and if it goes wrong there are ongoing costs and potential losses to crop yield and quality over a number of years. Early identification and timely intervention is vital for a successful weed control programme. This guide for the identification of broadleaf weeds is a partner to the ute guide for Grass Weeds of Arable Crops. FAR and its Maize Research Committee hope that the photos in these guides will become a useful field reference, enabling you to identify your weed pests in their early growth stages for successful management and improved profitability. Nick Pyke, Chief Executive, Foundation for Arable Research Broadleaf Weeds of Arable Crops Ute Guide 1
Contents How to use this booklet Broadleaf weeds by cotyledon shape: Round: Annual nettle (Urtica urens) Stagger weed (Stachys arvensis) Henbit (Lamium amplexicaule) Californian thistle (Cirsium arvense) Scotch thistle (Cirsium vulgare) Nodding thistle (Carduus nutans) Broad-leaved fleabane (Conyza sumatrensis) Wavy bitter cress (Cardamine flexuosa) Oval: Chickweed (Stellaria media) Mouse-ear chickweed (Cerastium glomeratum) Scarlet pimpernel (Anagalis arvensis) Club narrow: Twin cress (Lepidium didymum) Broad-leaved dock (Rumex obtusifolius) Hemlock (Conium maculatum) Oxtongue (Helminthotheca echioides) Redroot (Amaranthus powellii) Prostrate amaranth (Amaranthus deflexus) Purple amaranth (Amaranthus lividus) Green amaranth (Amaranthus viridis) Cornbind (Fallopia convolvulus) Bathurst bur (Xanthium spinosum) 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 2 Oblong: Fathen (Chenopodium album) Willow weed (Persicaria maculosa) Water pepper (Persicaria hydropiper) Apple of Peru (Nicandra physalodes) Purslane (Portulaca oleracea) Beggars ticks (Bidens frondosa) Groundsel (Senecio vulgaris) 25 26 27 28 29 30 31 Linear: Wire weed (Polygonum aviculare) Spurrey (Spergula arvensis) 32 33 Spear: Fumitory (Fumaria muralis) Thorn apple (Datura stramonium) 34 35 Egg: 36 37 Black nightshade (Solanum nigrum) Sow thistle (Sonchus oleraceous) Spade: Creeping mallow (Modiola caroliniana) 38 Scrambling speedwell (Veronica persica) 39 Large-flowered mallow (Malva sylvestris) 40 Triangular: Galinsoga (Galinsoga parviflora) 41 Heart: Wild radish (Raphanus raphanistrum) 42 Kidney: Wild turnip (Brassica rapa) Pink bindweed (Calystegia sepium) 43 44 None: 45 45 Pink shamrock (Oxalis vallicola) Fishtail oxalis (Oxalis latifolia)
How to use this booklet Broadleaf weeds can be readily identified at the seedling stage through a combination of their cotyledon and first leaf shapes. are otherwise known as seedleaves, and usually broadleaf plants produce a pair prior to true leaf production. are firstly assigned an overall shape (main key on page margin) and then within these groups the shape of the apex (tip) and base of the cotyledons are described according to the illustrations below. Apex rounded cotyledons first leaves The most obvious characters of the first leaves are then described to further assist identification. Base pointed flat indented notched rounded indented notched Broadleaf Weeds of Arable Crops Ute Guide flat tapered 3
Annual nettle (Urtica urens) 4 Apex notched Base rounded, stalked round Oval, toothed, with stinging prickles
round Apex indented Base flat, stalked Heart-shaped, round toothed, slightly hairy Stagger weed (Stachys arvensis) 5
Henbit (Lamium amplexicaule) 6 Apex flat Base notched, stalked Heart-shaped, bluntly toothed, slightly hairy round
round Apex rounded Base tapered, stalkless Oval, becoming deeply notched with long prickles Californian thistle (Cirsium arvense) 7
Scotch thistle (Cirsium vulgare) 8 Apex rounded Base tapered, stalkless Oval, older leaves only deeply loped, short, fine prickles round
round Apex rounded Base tapered, stalkless Long oval, toothed, becoming deeply lobed, hard prickles Nodding thistle (Carduus nutans) 9
Broad-leaved fleabane (Conyza sumatrensis) 10 Apex rounded Base rounded, stalked Oval, becoming longer, hairy and soft to touch round
round Apex indented Base rounded, stalked Young leaves kidney-shaped, becoming deeply divided as new leaves grow longer Wavy bitter cress (Cardamine flexuosa) 11
Chickweed (Stellaria media) 12 Apex pointed Base rounded, stalked oval Oval, pointed, thin and easily bruised
oval Apex bluntly pointed stalkess Base tapered, Oval, hairy Annual mouse-ear chickweed (Cerastium glomeratum) 13
Scarlet pimpernel (Anagalis arvensis) 14 Apex pointed Base flat, stalked Elliptical, smooth, black dots underneath oval
club narrow Apex rounded Base tapered, stalked First leaves with few lobes, later with many Twin cress (Lepidium didymum) 15
Broad-leaved dock (Rumex obtusifolius) 16 Apex rounded stalked Base tapered, short- First leaf round, later large, elongated, wavy club narrow
club narrow Apex rounded Base tapered, stalked First leaf in three parts each deeply indented, later carrot-like, upright Hemlock (Conium maculatum) 17
Oxtongue (Helminthotheca echioides) 18 Apex rounded Base tapered, stalkless club narrow Elongated, very rough to touch, bristly
Apex slightly pointed stalked Base tapered, club narrow Oval, notched Red stem Redroot (Amaranthus powellii) 19
Prostrate amaranth (Amaranthus deflexus) 20 Apex slightly pointed stalked Base tapered, Oval, notched club narrow
club narrow Apex slightly pointed stalked Base tapered, Oval, notched Purple amaranth (Amaranthus lividus) 21
Green amaranth (Amaranthus viridis) 22 Apex slightly pointed stalked Base tapered, Oval, very deeply notched club narrow
club narrow Apex slightly pointed stalkless Base tapered, Heart-shaped Cornbind (Fallopia convolvulus) 23
Bathurst bur (Xanthium spinosum) 24 Apex rounded Base tapered, stalkless Egg-shaped, becoming trident-shaped, spines at base club narrow
oblong Apex rounded Base tapered, stalked Fleshy, with fine, sugar-like crystals on new leaves Fathen (Chenopodium album) 25
Willow weed (Persicaria maculosa) 26 Apex rounded stalked Base rounded, Elongated with dark thumb print at centre oblong
oblong Apex rounded Base rounded, stalked Elongated, wavy, pale green Water pepper (Persicaria hydropiper) 27
Apple of Peru (Nicandra physalodes) 28 Apex rounded Base tapered, stalked Egg-shaped, veins prominent, becoming wavy later oblong
oblong Apex rounded stalked Base tapered, short- Thick, succulent, often with red trim Purslane (Portulaca oleracea) 29
Beggars ticks (Bidens frondosa) 30 Apex rounded Base tapered, stalked oblong 3 or 5 lance-shaped, toothed leaflets
oblong Apex rounded Base tapered, stalked Fleshy, shallow to deeply toothed Groundsel (Senecio vulgaris) 31
Wire weed (Polygonum aviculare) 32 Apex rounded stalkless Base not tapered, Elongated, not wavy, sometimes red tinged linear
linear Rod- or needle-like Rod- or needle-like, clammy to touch Spurrey (Spergula arvensis) 33
Fumitory (Fumaria muralis) 34 Apex pointed Base tapered, stalkless spear Several divided and toothed leaflets
Apex pointed stalked Base tapered, short- spear Elongated, becoming coarsely toothed, pungent when crushed Thorn apple (Datura stramonium) 35
Black nightshade (Solanum nigrum) 36 Apex pointed stalked Base tapered, hairy, Egg-shaped to oval, light green, hairy egg
egg Apex rounded Base rounded, stalkless Round becoming elongated and deeply lobed, blue-green, spiky teeth Sow thistle (Sonchus oleraceous) 37
Creeping mallow (Modiola caroliniana) 38 Apex pointed Base indented, stalked spade Round, toothed becoming deeply divided
spade Apex rounded Base flat, stalked Triangular to egg-shaped, bluntly toothed, hairy Scrambling speedwell (Veronica persica) 39
Large-flowered mallow (Malva sylvestris) 40 Apex rounded Base indented, stalked spade Round, 5-lobed, crinkled
triangular Apex rounded Base flat, stalked Oval, toothed, hairy margins Galinsoga (Galinsoga parviflora) 41
Wild radish (Raphanus raphanistrum) 42 Apex notched Base rounded, stalked Rough, hairy, toothed becoming deeply lobed heart
kidney Apex notched Base flat, stalked Oval, bristly-hairy, toothed becoming deeply lobed Wild turnip (Brassica rapa) 43
Pink bindweed (Calystegia sepium) 44 Apex shallow notch stalked Base indented, Large, triangular kidney
no cotyledons None Three leaflets, each deeply notched Pink shamrock (Oxalis vallicola) Fishtail oxalis leaves are less rounded than pink shamrock Fishtail oxalis (Oxalis latifolia) 45
cm 0 1 2 3 4 5 6 7 Designed by R.G. and F.J. Richardson, Victoria, Australia 8 9 10 11 12 13 14