Effects of Weed Infestation on Crop Yield and Quality

  • R. J. Stephens


Weeds are plants in the wrong place. For the purposes of this book any plant competing with cultivated plants or that in some other way interferes with man’s legitimate activities is considered to be a weed. Algae, mosses, liverworts, ferns and flowering plants all can qualify as weeds. Annuals, rarely biennials and both herbaceous and woody perennials may all be weeds. Crop plants become weeds themselves when they persist or regenerate in succeeding crops where they may act as sources of pests and disease pathogens. Why control weeds? Early farmers probably harvested a mixture of several ‘crops’ including some species now regarded as weeds, but the unpleasant tasting, poisonous or least productive components of the mixture would soon have been actively discouraged. At first this was by hand pulling, then by hoeing, cultivation and crop rotation, and in very recent times by seed cleaning and the use of herbicides. But in many parts of the world the extent of cultivation is still determined by the area that each family can keep clean by hand during the critical early period of crop establishment.


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Further Reading

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Copyright information

© R. J. Stephens 1982

Authors and Affiliations

  • R. J. Stephens
    • 1
  1. 1.School of Biological SciencesUniversity of BathUK

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