BROADLEAF WEEDS of ARABLE CROPS The Ute Guide Trevor James, AgResearch ADDING VALUE TO THE BUSINESS OF CROPPING Published by Foundation for Arable Research PO Box 23133, Hornby, Christchurch 8441 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. Broadleaf Weeds of Arable Crops Ute Guide 1 Contents 2 How to use this booklet 3Oblong: Fathen (Chenopodium album) 25 Broadleaf weeds by cotyledon shape: Willow weed (Persicaria maculosa) 26 Round: Annual nettle (Urtica urens) 4 Water pepper (Persicaria hydropiper) 27 Stagger weed (Stachys arvensis) 5 Apple of Peru (Nicandra physalodes) 28 Henbit (Lamium amplexicaule) 6 Purslane (Portulaca oleracea) 29 Californian thistle (Cirsium arvense) 7 Beggars’ ticks (Bidens frondosa) 30 Scotch thistle (Cirsium vulgare) 8 Groundsel (Senecio vulgaris) 31 Nodding thistle (Carduus nutans) 9 Linear: Wire weed (Polygonum aviculare) 32 Broad-leaved fleabane (Conyza sumatrensis) 10 Spurrey (Spergula arvensis) 33 Wavy bitter cress (Cardamine flexuosa) 11 Spear: Fumitory (Fumaria muralis) 34 Oval: Chickweed (Stellaria media) 12 Thorn apple (Datura stramonium) 35 Mouse-ear chickweed (Cerastium glomeratum) 13 Egg: Black nightshade (Solanum nigrum) 36 Scarlet pimpernel (Anagalis arvensis) 14 Sow thistle (Sonchus oleraceous) 37 Club narrow: Twin cress (Lepidium didymum) 15 Spade: Creeping mallow (Modiola caroliniana) 38 Broad-leaved dock (Rumex obtusifolius) 16 Scrambling speedwell (Veronica persica) 39 Hemlock (Conium maculatum) 17 Large-flowered mallow (Malva sylvestris) 40 Oxtongue (Helminthotheca echioides) 18 Triangular: Galinsoga (Galinsoga parviflora) 41 Redroot (Amaranthus powellii) 19 Heart: Wild radish (Raphanus raphanistrum) 42 Prostrate amaranth (Amaranthus deflexus) 20 Purple amaranth (Amaranthus lividus) 21 Kidney: Wild turnip (Brassica rapa) 43 Green amaranth (Amaranthus viridis) 22 Pink bindweed (Calystegia sepium) 44 Cornbind (Fallopia convolvulus) 23 None: Pink shamrock (Oxalis vallicola) 45 Bathurst bur (Xanthium spinosum) 24 Fishtail oxalis (Oxalis latifolia) 45 How to use this booklet cotyledons Broadleaf weeds can be readily identified at the seedling stage through a combination of their cotyledon and first leaf shapes. Cotyledons are otherwise known as seed- leaves, and usually broadleaf plants produce a pair prior to true leaf production. first Cotyledons are firstly assigned an overall leaves shape (main key on page margin) and then within these groups the shape of the apex The most obvious characters of the first (tip) and base of the cotyledons are described leaves are then described to further assist according to the illustrations below. identification. Apex Base rounded pointed flat indented notched rounded indented notched flat tapered Broadleaf Weeds of Arable Crops Ute Guide 3 Annual nettle (Urtica urens) 4 Cotyledons Apex notched Base rounded, stalked Leaves Oval, toothed, with stinging prickles round Cotyledons round Apex indented Base flat, stalked Leaves Heart-shaped, round toothed, slightly hairy Stagger weed (Stachys arvensis) 5 Henbit (Lamium amplexicaule) 6 Cotyledons Apex flat Base notched, stalked Leaves Heart-shaped, bluntly toothed, slightly hairy round Cotyledons round Apex rounded Base tapered, stalkless Leaves Oval, becoming deeply notched with long prickles Californian thistle (Cirsium arvense) 7 Scotch thistle (Cirsium vulgare) 8 Cotyledons Apex rounded Base tapered, stalkless Leaves Oval, older leaves only deeply loped, short, fine prickles round Cotyledons round Apex rounded Base tapered, stalkless Leaves Long oval, toothed, becoming deeply lobed, hard prickles Nodding thistle (Carduus nutans) 9 Broad-leaved fleabane (Conyza sumatrensis) 10 Cotyledons Apex rounded Base rounded, stalked Leaves Oval, becoming longer, hairy and soft to touch round Cotyledons round Apex indented Base rounded, stalked Leaves Young leaves kidney-shaped, becoming deeply divided as new leaves grow longer Wavy bitter cress (Cardamine flexuosa) 11 Chickweed (Stellaria media) 12 Cotyledons Apex pointed Base rounded, stalked Leaves Oval, pointed, thin and easily bruised oval Cotyledons oval Apex bluntly pointed Base tapered, stalkess Leaves Oval, hairy Annual mouse-ear chickweed (Cerastium glomeratum) 13 Scarlet pimpernel (Anagalis arvensis) 14 Cotyledons Apex pointed Base flat, stalked Leaves Elliptical, smooth, black dots underneath oval Cotyledons club narrow Apex rounded Base tapered, stalked Leaves First leaves with few lobes, later with many Twin cress (Lepidium didymum) 15 Broad-leaved dock (Rumex obtusifolius) 16 Cotyledons Apex rounded Base tapered, short- stalked Leaves First leaf round, later large, elongated, wavy club narrow Cotyledons club narrow Apex rounded Base tapered, stalked Leaves First leaf in three parts each deeply indented, later carrot-like, upright Hemlock (Conium maculatum) 17 Oxtongue (Helminthotheca echioides) 18 Cotyledons Apex rounded Base tapered, stalkless Leaves Elongated, very rough to touch, bristly club narrow Cotyledons club narrow Apex slightly pointed Base tapered, stalked Leaves Oval, notched Red stem Redroot (Amaranthus powellii) 19 Prostrate amaranth (Amaranthus deflexus) 20 Cotyledons Apex slightly pointed Base tapered, stalked Leaves Oval, notched club narrow Cotyledons club narrow Apex slightly pointed Base tapered, stalked Leaves Oval, notched Purple amaranth (Amaranthus lividus) 21 Green amaranth (Amaranthus viridis) 22 Cotyledons Apex slightly pointed Base tapered, stalked Leaves Oval, very deeply notched club narrow Cotyledons club narrow Apex slightly pointed Base tapered, stalkless Leaves Heart-shaped Cornbind (Fallopia convolvulus) 23 Bathurst bur (Xanthium spinosum) 24 Cotyledons Apex rounded Base tapered, stalkless Leaves Egg-shaped, becoming trident-shaped, spines at base club narrow Cotyledons oblong Apex rounded Base tapered, stalked Leaves Fleshy, with fine, sugar-like crystals on new leaves Fathen (Chenopodium album) 25 Willow weed (Persicaria maculosa) 26 Cotyledons Apex rounded Base rounded, stalked Leaves Elongated with dark ‘thumb print’ at centre oblong oblong Cotyledons Apex rounded Base rounded, stalked Leaves Elongated, wavy, pale green Water pepper (Persicaria hydropiper) 27 Apple of Peru (Nicandra physalodes) 28 Cotyledons Apex rounded Base tapered, stalked Leaves Egg-shaped, veins prominent, becoming wavy later oblong Cotyledons oblong Apex rounded Base tapered, short- stalked Leaves Thick, succulent, often with red trim Purslane (Portulaca oleracea) 29 Beggars’ ticks (Bidens frondosa) 30 Cotyledons Apex rounded Base tapered, stalked Leaves 3 or 5 lance-shaped, toothed leaflets oblong oblong Cotyledons Apex rounded Base tapered, stalked Leaves Fleshy, shallow to deeply toothed Groundsel (Senecio vulgaris) 31 Wire weed (Polygonum aviculare) 32 Cotyledons Apex rounded Base not tapered, stalkless Leaves Elongated, not wavy, sometimes red tinged linear linear Cotyledons Rod- or needle-like Leaves Rod- or needle-like, clammy to touch Spurrey (Spergula arvensis) 33 Fumitory (Fumaria muralis) 34 Cotyledons Apex pointed Base tapered, stalkless Leaves Several divided and toothed leaflets spear Cotyledons spear Apex pointed Base tapered, short- stalked Leaves Elongated, becoming coarsely toothed, pungent when crushed Thorn apple (Datura stramonium) 35 Black nightshade (Solanum nigrum) 36 Cotyledons Apex pointed Base tapered, hairy, stalked Leaves Egg-shaped to oval, light green, hairy egg Cotyledons egg Apex rounded Base rounded, stalkless Leaves Round becoming elongated and deeply lobed, blue-green, spiky teeth Sow thistle (Sonchus oleraceous) 37 Creeping mallow (Modiola caroliniana) 38 Cotyledons Apex pointed Base indented, stalked Leaves Round, toothed becoming deeply divided spade Cotyledons spade Apex rounded Base flat, stalked Leaves Triangular to egg-shaped, bluntly toothed, hairy Scrambling speedwell (Veronica persica) 39 Large-flowered mallow (Malva sylvestris) 40 Cotyledons Apex rounded Base indented, stalked Leaves Round, 5-lobed, crinkled spade triangular Cotyledons Apex rounded Base flat, stalked Leaves Oval, toothed, hairy margins Galinsoga (Galinsoga parviflora) 41 Wild radish (Raphanus raphanistrum) 42 Cotyledons Apex notched Base rounded, stalked Leaves Rough, hairy, toothed becoming deeply lobed heart Cotyledons kidney Apex notched Base flat, stalked Leaves Oval, bristly-hairy, toothed becoming deeply lobed Wild turnip (Brassica rapa) 43 Pink bindweed (Calystegia sepium) 44 Cotyledons Apex shallow notch Base indented, stalked Leaves Large, triangular kidney Cotyledons None no cotyledons Leaves Fishtail oxalis leaves are less rounded than Three leaflets, each deeply notched pink shamrock Pink shamrock (Oxalis vallicola) Fishtail oxalis (Oxalis latifolia) 45 Designed by R.G. and F.J. Richardson, Victoria, Australia cm 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14.