Pest control is the set of practices used to reduce populations of organisms that interfere with human wellbeing, agriculture, property or natural ecosystems. Pests may be insects, rodents, weeds, fungi, or other organisms that damage crops, spread disease, spoil food, or degrade structures. Management approaches range from simple exclusion and sanitation to chemical treatments and coordinated ecological strategies. For concise lists and classifications, see comprehensive pest species lists.

Characteristics and common groups

Pests are defined by impact rather than by taxonomy: a species becomes a pest where its presence causes unacceptable economic loss, health risk or ecological harm. Common urban pests include rats, mice, cockroaches, flies and stored‑product beetles. In agriculture, important groups are aphids, caterpillars, mites, nematodes, fungal pathogens and competitive plants (weeds). Some organisms are occasional pests when conditions favor them, while others are persistent and require continuous control.

Methods of pest control

Control techniques fall into several broad categories that can be used alone or in combination. Choice of method depends on the pest, the environment, human safety, cost and regulatory constraints. For health-related guidance and safe use of products consult local authorities and professional services: public health guidance.

  • Cultural methods: crop rotation, planting dates, irrigation management and sanitation to make sites less favorable to pests.
  • Mechanical and physical controls: traps, barriers, screens, heat or cold treatments, and manual removal.
  • Biological control: use of predators, parasites or microbial agents to suppress pest populations; often applied in agriculture and horticulture.
  • Chemical control: pesticides, insecticides, herbicides and rodenticides; effective but can cause non‑target impacts and require careful application.
  • Integrated Pest Management (IPM): a decision‑based framework that combines monitoring, threshold‑based interventions, and multiple control tactics to reduce reliance on chemicals.
  • Humane and exclusion strategies: sealing entry points, habitat modification, repellents and live capture with relocation where legal and appropriate; some electronic repellents are marketed but their effectiveness is variable.

History and development

People have managed pests since the beginnings of agriculture, using practices such as hand‑picking, crop selection and simple barriers. Over centuries, botanical compounds (for example pyrethrum and nicotine preparations) and sulfur were used. The 20th century brought synthetic pesticides that initially offered dramatic control but later revealed environmental and human health drawbacks — most famously with persistent compounds that accumulated in ecosystems. These problems helped spur the development of IPM and stronger regulations, and encouraged research into biological agents and safer chemistries.

Importance, risks and notable distinctions

Effective pest control protects food supplies, safeguards public health and preserves built and natural environments. However, several risks must be managed: overuse of chemicals can lead to pesticide resistance, kill beneficial organisms (pollinators, natural enemies), contaminate water and soil, and pose direct risks to people and pets. Distinctions important to management include the difference between a pest and a beneficial species, and between an established pest and an invasive species that spreads rapidly into new regions. Economic thresholds—levels of pest density that justify intervention—are central to IPM strategies.

Practical pest management balances efficacy, safety and sustainability. Homeowners, farmers and public agencies increasingly rely on monitoring, exclusion, habitat modification and targeted, least‑harmful treatments to keep pests at acceptable levels. For more on economic impacts and policy, see economic analyses and for ecological effects consult ecosystem impact summaries. General definitions and introductory resources are available at pest control overview.