What does infestant mean?
An infestant is an organism or other agent that occupies a place, host, or body, usually in large numbers and often with harmful results. The word is especially associated with insects, mites, microorganisms, and other pests that affect plants, animals, food, buildings, or human health. It is also used more broadly for something that spreads persistently or becomes difficult to eliminate. In phrases such as “a common garden infestant” and “a serious crop infestant,” it identifies the source of an infestation rather than the condition itself. The term is more characteristic of formal, scientific, agricultural, and pest-control writing than of ordinary conversation, where “pest” or “parasite” is often more natural. Distinguishing it from “infestation” is important: the infestant is the offending organism or agent, while the infestation is the unwelcome presence or damage it produces.
nounAn organism or other agent that infests a place, host, or organism, especially one occurring in large numbers and causing damage or irritation.
- An organism or agent that infests a place, host, or organism, especially in large numbers.
"The insecticide was designed to control the common garden infestant without harming beneficial insects."
"The aphid, a serious infestant of roses, spread rapidly throughout the greenhouse."
"Researchers tested a chemical that may protect stored grain from a destructive infestant."
The plural is used when referring to multiple individual organisms or agents that infest, though the word itself is uncommon.
"These infestants can spread through imported grain and contaminate storage facilities."
An infestant is best imagined as the unwelcome guest in a swarm: the individual organism behind a larger infestation.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does infestant come from?
“Infestant” was formed in English from “infest” and the suffix “-ant,” which can indicate an agent or person or thing that performs an action. The verb “infest” derives from Latin infestare, meaning “to make hostile” or “to attack,” which developed into its modern sense of occupying a place or body in large numbers. The English agent noun appeared during the early modern period and is now chiefly used in technical contexts.
Related word forms
How infestant is actually used
This is a relatively uncommon, formal or technical noun. It is more common in specialist writing about agriculture, pest control, biology, and medicine than in everyday speech.
Easily confused with infestant
An infestant is the organism or agent responsible for an infestation, whereas an infestation is the condition or infestation itself.