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A pest is an organism which harms man or his property.

Less than 0.1% of insects are pests.

Insects can cause damage directly (by their feeding or making of shelters) or indirectly by other means.


  1. Chewing of plants
    e.g. grasshoppers, caterpillars, leaf miners, root chewing beetle larvae, stem borers.
  2. Piercing and sucking
    Direct removal of plant sap or animal blood
    e.g.  aphids, vegetable bugs, mites, bed bugs, lice, ticks


  1. Transmitters of disease (vectors) - from plant to plant or animal to animal
    e.g. plant viruses and bacteria transmitted via aphids and leafhoppers, malaria, dengue fever and heartworm via mosquitoes.
  2. Disease entering independently through wound site of feeding or egg laying.
    e.g. bacterial rots of cotton, infected bites on animals.
  3. Spoiling
    e.g. webbing and faeces in food products, cockroach faeces on goods, sooty  mould growing on honeydew exudate from aphids leading to both spoilage and reduction of photosynthesis by affected foliage.
  4. Toxic saliva or allergies
    e.g. flea irritation on dogs, mosquitoes and sandflies on humans.

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