Pest (organism)

Carpet beetle larvae damaging a specimen of Sceliphron destillatorius in an entomological collection

A pest is an animal which is detrimental to humans or human concerns. It is a loosely defined term, often overlapping with the related terms vermin, weeds, parasites and pathogens. In its broadest sense, a pest is a competitor of humanity.

Usage of the term

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

Often animals are derided as pests as 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.

The term pest may be used to refer specifically to harmful animals but is also often taken to mean all harmful organisms including weeds, plant pathogenic fungi and viruses. Pesticides are chemicals and other agents (e.g. beneficial micro-organisms) that are used to control or protect other organisms from pests. The related term vermin has much overlap with pest, but generally only includes those creatures that are seen to be vectors of diseases.

It is possible for an animal to 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 (plant pests) 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.

Plants may be consisidered pests if an invasive species. Any prolific animal or plant may be considered pests.

The greatest importance as pests (in the order of economic importance) are insects, mites, nematodes and gastropods.

Invertebrate pests

Insects

Further information: Insect bites and stings and Category:Pest insects

Caterpillars cause crop damage

Termites cause structural damage

• Ants, cockroaches, flies and wasps are household pests, typically as they consume human food
• Aphids and caterpillars cause damage to crop plants
• Lice, fleas and bed bugs can all cause skin irritation
• Mosquitoes, tsetse flies and kissing bugs cause irritation and carry disease
• Termites, silverfish, woodworm and wood ants cause structural damage
• Bookworms, carpet beetles and clothes moths cause non-structural damage
• Gypsy moths attack hardwood trees (see Gypsy moths in the United States)

Nematodes

• Root-knot nematode
• Soybean cyst nematode
• Potato cyst nematode

Mites

• Chiggers cause skin irritation
• Sarcoptes scabiei causes scabies
• Ticks and mites cause irritation and can spread disease

Gastropods

Some slugs are pests in both agriculture and gardens. Their significance is increasing drastically. Deroceras reticulatum is a worldwide distributed slug pest. Local importance slug pests include: Deroceras spp., Milax spp., Tandonia sp., Limax spp., Arion spp. and some species of Veronicellidae: Veronicella sloanei.

Land snail pests include:

• Helix aspersa damages citrus fruits in California,
• Cernuella virgata, Theba pisana and Cochlicella spp. decrease quality of grains when harvested with the product in South Australia.
• Achatina fulica damages vegetables and ornamental plants in the Pacific region.
• Succinea costaricana damages ornamental plants in Costa Rica.
• Ovachlamys fulgens damages ornamental plants and orchids in Costa Rica.
• Other species considered to be pests include: Amphibulima patula dominicensis, Zachrysia provisoria and Bradybaena similaris.

Freshwater snail pests include:

• Pomacea canaliculata damages rice in Southeast Asia.
• Bulinus sp., Biomphalaria spp. and Oncomelania are intermediate hosts of schistosomes causing schistosomiasis.
• Various species in Lymnaeidae are intermediate hosts of fasciolosis.

Vertebrate pests

Seagulls steal human food

Mammals

• Mice, rats and other small rodents cause infestations
• Foxes, opossums, raccoons and bears eat waste
• Gophers and moles destroy lawns
• Feral cats and feral dogs eat human food and carry disease
• White-tailed deer are now seen as pests in many suburban and exurban areas of the US, though not in more rural areas.
• Eastern Grey Squirrel are seen as pests in Britain and Ireland because of the decline of Red Squirrel populations

Birds

• Pigeons and seagulls eat human food and carry disease^{[citation needed]}
• Many birds, such as crows, eat crop seed
• Canada Goose; non-migratory birds of this species are now widely regarded as pests in the United States (see Canada Goose#Relationship with humans).

See also

• List of parasites of humans
• List of common household pests
• Lists of plant diseases
• Invasive species
• Weeds
• Vermin
• Synanthrope
• Urban wildlife
• Pest control
• Nuisance wildlife management
• Home stored product entomology

Further reading

• Burch, John B.. 1960. Some snails and slugs of quarantine significance to the United States. U.S. Dept. Argriculture, Agricultural Research Service 82(1): 73 pp

External links

• UF/IFAS Pest Alert Web site - arthropods, nematodes and plant diseases affecting humans, livestock/pets, agricultural and ornamental plants.