Crop Protection

    Cards (12)

    • Weeds compete with crop plants, while other pests and diseases damage crop plants. All of which reduce productivity.
    • Annual weeds
      These have rapid growth, a short life cycle; high seed output and long-term seed viability.
    • Perennial weeds
      Contain underground storage organs and use vegetative reproduction. These underground storage organs will grow into another weed even if the (surface) plant itself has been removed.
    • Most of the pests of crop plants are invertebrate animals such as insects, nematode worms and molluscs (slugs).
      Plant diseases can be caused by fungi, bacteria or viruses, which are often carried by invertebrates.
    • Ploughing, weeding and crop rotation are cultural methods in controlling weeds, pests and diseases.
    • Selective herbicides have a greater effect on certain plant species (broad leaved plants).
      They only kill a particular type of weed, not all plants they come into contact with.
    • Systemic simply means that it travels into the vascular system of the plant.
      • Systemic herbicides - spreads through the vascular system of the plant including the underground storage organs and prevents regrowth.
      • Systemic insecticides, molluscicide and nematicide – spreads through the vascular system of plants and kill pests feeding on plants.
    • The three problems associated with pesticides are:
      • toxicity to no-target species.
      • persistence in the environment.
      • bioaccumulation or biomagnification in food chains producing resistance pests.
    • Bioaccumulation is a build-up of a chemical in an organism.
      Biomagnification is an increase in the concentration of a chemical moving between trophic levels.
    • In biological control, the control agent is a natural predator, parasite or pathogen of the pest.
    • Integrated pest management uses a combination of biological control, cultural and chemical methods to control pests and diseases.
    • Risks associated with biological control methods
      The control organism my become an invasive species, parasite, prey on or be a pathogen of other species other than the pest.
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