Standard Article

Weed Species

  1. Charles T. Bryson

Published Online: 15 APR 2003

DOI: 10.1002/047126363X.agr240

Encyclopedia of Agrochemicals

Encyclopedia of Agrochemicals

How to Cite

Bryson, C. T. 2003. Weed Species. Encyclopedia of Agrochemicals. .

Author Information

  1. USDA-ARS, Stoneville, Mississippi

Publication History

  1. Published Online: 15 APR 2003

Abstract

Weeds are a major deterrent to agricultural and forest productivity and adversely effect urban, natural plant communities, and human and livestock health. Usually, the most troublesome weeds in an area originated somewhere else in the world. Weeds possess traits that give them biological, ecological, and reproductive advantages over non-weedy plants. Of the 8000 or so weeds in the world, about 200 species are responsible for about 95% of the weed problems of food, feed, fiber, and livestock production. These and additional species cost billions of U.S. dollars in forestry and urban areas and threaten species diversity in natural communities worldwide. About 73% of the world's weeds are dicots (broadleaf weeds) and 25% are monocots (grasses, sedges, rushes, and other monocot groups), whereas the remaining 2% are peridiophytes (ferns and fern allies) and gymonsperms (conifers and conifer allies). An overview is provided for weeds, including a general definition, economic losses, spread, identification sources, population shifts, thresholds, competitive index, effects on tillage production systems, and major species of the world in agriculture, forestry, urban areas, and natural communities.

Keywords:

  • abutilon theophrastii;
  • African mile-a-minute;
  • ageratum conyzoides;
  • ageratum houstonianum;
  • agropyron repens;
  • amaranthus spp.;
  • amaranthus retroflexus;
  • American burnweed;
  • ampelopsis;
  • annual bluegrass;
  • annual sowthistle;
  • arundo donax L.;
  • azolla pinnata;
  • baccharis halimifolia;
  • barnyardgrass;
  • bermudagrass;
  • bidens pilosa;
  • bigroot morningglory;
  • biotypes;
  • black nightshade;
  • black willow;
  • brackenfern;
  • Brazilian peppertree;
  • broadleaf weeds;
  • bromus tectorum;
  • broomrapes;
  • brunnichia ovata;
  • bulbostylis;
  • bull thistle;
  • campsis radicans;
  • Canada thistle;
  • carduus;
  • carex;
  • centaurea;
  • chenopodium album;
  • Chinaberry;
  • Chinese privet;
  • Chinese tallow tree;
  • Chinese tamarisk;
  • chromolaena odorata;
  • cicuta;
  • cirsium arvense;
  • cirsium vulgare;
  • cladium;
  • climbing hempweed;
  • coffee senna;
  • cogongrass;
  • commelina benghalensis;
  • commelina diffusa;
  • common cocklebur;
  • common dandelion;
  • common lambsquarters;
  • common purslane;
  • common weeds;
  • competitive index;
  • computer aids;
  • coniunm maculatum;
  • convolvulus arvensis;
  • conyza canadensis;
  • corn;
  • coronopus didymus;
  • cotton;
  • cottonwood;
  • crabgrass;
  • crop interference;
  • crotalaria spectabilis;
  • cucurbita texana;
  • cuscuta;
  • cynodon dactylon;
  • cyperus difformis;
  • cyperus esculentus;
  • cyperus iria;
  • cyperus rotundus;
  • datura stramonium L.;
  • dichromena;
  • dicots;
  • digitalis purpurea;
  • doveweed;
  • downy brome;
  • eastern baccharis;
  • eastern redcedar;
  • echinochloa colona;
  • echinochloa crus-gali;
  • echinochloa crus-galli;
  • eclipta;
  • eclipta prostrata;
  • eichhornia crassipes;
  • elaeagnus angustifolia;
  • eleocharis;
  • eleucine indica;
  • eleusine indica;
  • entireleaf morningglory;
  • environmental niche;
  • equisetum arvense;
  • erechtites hieraciifolia;
  • euphorbia esula;
  • European pepperwort;
  • field bindweed;
  • field horsetail;
  • fimbristylis;
  • foxglove;
  • fox-grapes;
  • fuirena;
  • galega officinalis;
  • giant reed;
  • giant salvinia;
  • glycine max;
  • goatsrue;
  • goosegrass;
  • gossypium hirsutum;
  • grain Sorghum;
  • grasses weeds;
  • gymnosperms;
  • hairy beggarticks;
  • hemicarpha;
  • hemp sesbania;
  • horsenettle;
  • horseweed;
  • hydrilla;
  • hydrilla verticillata;
  • imperata cylindrica;
  • invasive weeds;
  • ipomoea hederacea;
  • ipomoea purpurea;
  • ipomoea turbinata;
  • isolepis;
  • itchgrass;
  • ivyleaf morningglory;
  • Japanese honeysuckle;
  • jimsonweed;
  • johnsongrass;
  • junglerice;
  • juniperus occidentalis;
  • juniperus virginaina;
  • knapweeds;
  • kudzu;
  • kyllinga;
  • leafy spurge;
  • ligustrum sinense;
  • lipocarpha;
  • lonicera japonica;
  • lythrum salicaria;
  • marsh dayflower;
  • marsilea quadrifolia;
  • melia azedarach;
  • mikania cordata;
  • mikania micrantha;
  • mikania scandens;
  • mile-a-minute;
  • monocots;
  • morningglories;
  • mousetail;
  • murdannia keisak;
  • murdannia nudiflora;
  • myosurus minimus;
  • non-native weeds;
  • oryza sativa;
  • panicum repens;
  • natural plant community;
  • perennial sowthistle;
  • pinnate mosquitofern;
  • pinus edulis;
  • pinyon pine;
  • poa annua;
  • poison hemlock;
  • poison ivy;
  • poison oak;
  • poison sumac;
  • populus deltoids;
  • portulaca oleracea;
  • prickly sida;
  • psilocarya spp.;
  • pteridium aquilinum;
  • pterophytes;
  • pueraria montana;
  • purple loosestrife;
  • purple nutsedge;
  • quackgrass;
  • rattlebush;
  • redroot pigweed;
  • redvine;
  • rhus vermix;
  • rhynchospora;
  • rice;
  • rice flatsedge;
  • rottboellia cochinchinensis;
  • rushes;
  • Russian olive;
  • saccaharum officinarum;
  • salix nigra;
  • salvinia molesta;
  • sapium sabiferum;
  • schenoplectus spp.;
  • schinus terebinthifolius;
  • scirpus spp.;
  • scleria spp.;
  • sedges weeds;
  • senna obtusifolia;
  • senna occidentalis;
  • sesbania exaltata;
  • sesbania punicea;
  • showy crotalaria;
  • sibara;
  • sibara virginica;
  • sicklepod;
  • sida spinosa L.;
  • silverleaf nightshade;
  • sisymbrium altissimum;
  • smallflower umbrellasedge;
  • solanum carolinse;
  • solanum elaeagnifolium;
  • solanum nigrum L.;
  • solanum tampicense Dun.;
  • solanum torvum Sw.;
  • solanum viarum Dun.;
  • sonchus asper;
  • sonchus arvensis;
  • sonchus oleraceus;
  • sorghum halepense;
  • sorghum vulgare;
  • soybean;
  • spiny cocklebur;
  • spiny sowthistle;
  • spreading dayflower;
  • stinging nettle;
  • striga asiatica;
  • sugarcane;
  • swinecress;
  • tall morningglory;
  • tamarix chinensis;
  • taraxacum officinale;
  • texas gourd;
  • thistles;
  • torpedograss;
  • toxicodendron toxicarium;
  • toxicodendron diversilobum;
  • toxicodendron radicans;
  • tropical ageratums;
  • tropical soda apple;
  • tropical spiderwort;
  • troublesome weeds;
  • trumpetcreeper;
  • tumble mustard;
  • turkeyberry;
  • urtica dioica;
  • velvetleaf;
  • waterhyacinth;
  • weed definition;
  • weed identification;
  • weed shifts;
  • weed thresholds;
  • western juniper;
  • western poison oak;
  • wetland nightshade;
  • witchweed;
  • xanthium spinosum;
  • xanthium strumarium;
  • yellow nutsedge;
  • zea mays