A pest is a plant or animal detrimental to humans or human concerns including crops, livestock, and forestry. The term is also used of organisms that cause a nuisance, such as in the home. An older usage is of a deadly epidemic disease, specifically plague. In its broadest sense, a pest is a competitor of humanity.[1][2]


A pest is any living organism, whether animal, plant or fungus, which is invasive or troublesome to plants or animals, human or human concerns, livestock, or human structures. It is a loose concept, as an organism can be a pest in one setting but beneficial, domesticated or acceptable in another.

Pests often occur in high densities, making the damage they do even more detrimental. Termite

Animals are called pests when they cause damage to agriculture by feeding on crops or parasitising livestock, such as codling moth on apples, or boll weevil on cotton. An animal could also be a pest when it causes damage to a wild ecosystem or carries germs within human habitats. Examples of these include those organisms which vector human disease, such as rats and fleas which carry the plague disease, mosquitoes which vector malaria, and ticks which carry Lyme disease.

A species can be a pest in one setting but beneficial or domesticated in another (for example, European rabbits introduced to Australia caused ecological damage beyond the scale they inflicted in their natural habitat). Many weeds are also seen as useful under certain conditions, for instance Patterson's curse is often valued as food for honeybees and as a wildflower, even though it can poison livestock.

The term "plant pest" has a specific definition in terms of the International Plant Protection Convention and phytosanitary measures worldwide. A pest is any species, strain or biotype of plant, animal, or pathogenic agent injurious to plants or plant products.[3] Plants may be considered pests themselves if an invasive species.

The animal groups of greatest importance as pests (in order of economic importance) are insects, mites, nematodes and gastropods.[4] Plant pests can be classed as monophagous, oligophagous, and polyphagous according to how many hosts they have. Alternatively, they can be divided by feeding type, whether biting and chewing; piercing and sucking; or Lapping and chewing. Another approach is to class them by population presence as * key pests, occasional pests, and potential pests. In terms of population biology, there are population growth rate (r) pests; carrying capacity (k) pests; and r-k pests.

By taxon

Vertebrate pests



  • Bullfrogs cause problems to the ecosystems.
  • Cane toads have had serious negative effects on many ecosystems to which they have been introduced, especially in Australia. The toad's skin is toxic, killing many wild and domestic animals that attempt to eat it.



Insects and arachnids

Agricultural and domestic arthropods
Caterpillars cause crop damage
Termites cause structural damage
Tree and forest pests


Gastropod molluscs

These include slugs and land snail pests:

Some slugs are pests in agriculture and gardens.[4] Deroceras reticulatum is a worldwide slug pest.[4] Local importance slug pests include: Deroceras spp.,[4] Milax spp.,[4] Tandonia sp.,[4] Limax spp.,[4] Arion spp.[4] and some species of Veronicellidae:[4] Veronicella sloanei.[8]

Plant diseases


See also


  1. ^ Merriam-Webster dictionary, accessed 22 August 2012.
  2. ^ "Pest vermin". Britannica. Retrieved 24 August 2016. 
  3. ^ FAO Corporate Document Repository: Guidelines for Phytosanitary Certificates. Retrieved 1 August 2012
  4. ^ a b c d e f g h i j k Speiser B. (2002). "Chapter 219. Molluscicides". 506–508. doi:10.1201/NOE0824706326.ch219 PDF In: Pimentel D. (ed.) (2002). Encyclopedia of Pest Management. ISBN 978-0-8247-0632-6.
  5. ^ Lowe S., Browne M., Boudjelas S. and de Poorter M. (2000). 100 of the World’s Worst Invasive Alien Species. A selection from the Global Invasive Species Database. The Invasive Species Specialist Group (ISSG), a specialist group of the Species Survival Commission (SSC) of the World Conservation Union (IUCN), Auckland.
  6. ^ "ABC Wildwatch". Abc.net.au. Retrieved 2012-08-07. 
  7. ^ Greenhall, Arthur M. 1961. Bats in Agriculture. A Ministry of Agriculture Publication. Trinidad and Tobago
  8. ^ a b c d PD-icon.svg Stange L. A. (created September 2004, updated March 2006). "Snails and Slugs of Regulatory Significance to Florida" Archived 2010-12-02 at the Wayback Machine.. Division of Plant Industry, Florida Department of Agriculture and Consumer Services. Accessed 27 August 2010.
  9. ^ Villalobos M. C., Monge-Nájera J., Barrientos Z. & Franco J. (1995). "Life cycle and field abundance of the snail Succinea costaricana (Stylommatophora: Succineidae), a tropical pest". Revista de Biología Tropical 43: 181-188. PDF Archived 2011-07-17 at the Wayback Machine..
  10. ^ Barrientos Z. (1998). "Life history of the terrestrial snail Ovachlamys fulgens (Stylommatophora: Helicarionidae) under laboratory conditions". Revista de Biología Tropical 46(2): 369-384. PDF. HTM in the Google chache.

Further reading

External links