Pesticide

Definition

Any substance or mixture of substances intended to prevent, destroy, repel, or mitigate pests, including insects, arachnids, nematodes, fungi, and weeds. In entomological contexts, the term most commonly refers to insecticides (targeting insects) and acaricides (targeting mites and ticks), though it encompasses the full range of pest-control chemistries. Pesticides may act through contact, ingestion, or systemic translocation within plants, and their selectivity ranges from broad-spectrum to highly taxon-specific.

Etymology

From Latin pestis (plague, pest) + caedere (to kill), via English pest + -cide (killer).

Example

Integrated pest management programs often combine reduced-risk pesticides such as Bacillus thuringiensis formulations for lepidopteran larvae with biological control agents to minimize non-target effects on pollinators and natural enemies.

Synonyms

• plant protection product
• crop protection agent

Related Terms

• Insecticide
• acaricide
• Integrated Pest Management
• resistance
• Biopesticide
• Insect growth regulator
• LD50
• residual toxicity

Usage Notes

Specialists distinguish pesticides by target taxon (insecticide, acaricide, nematicide, molluscicide) and mode of action (contact, stomach poison, systemic). The broader term 'pesticide' is often used in policy and regulatory contexts, whereas entomologists typically specify 'insecticide' when referring to arthropod-targeting products. 'Pesticide' is sometimes avoided in precision agriculture discourse in favor of 'crop protection product' to emphasize stewardship, though this is marketing-driven rather than technical. Contrast with biopesticide, which denotes microbial or biochemical agents, and with repellent, which deters without killing.