Glossary

Section: Reference · 45 terms

Plain, accurate definitions for the terms used across this desk. Where a definition carries a safety or legal meaning (signal word, LD₅₀), the limits are stated with it.

Action threshold: A pre-set level of pest presence or damage at which control action is justified.
Aggregation pheromone: A chemical signal that draws members of a species together at a site.
Allergen: A substance, often a protein, that provokes an allergic immune response in sensitised people.
Anaphylaxis: A rapid, severe, potentially life-threatening allergic reaction requiring emergency care.
Bait aversion: Heritable avoidance of a bait or one of its ingredients, selected by prior bait exposure.
Biological control: Use of living organisms — predators, parasitoids, pathogens — to suppress a pest population.
Carrying capacity: The population level an environment can sustain given food, water, and harborage.
Chitin: The structural polysaccharide of insect cuticle; its synthesis is targeted by some IGRs.
Cross-resistance: Resistance to one insecticide conferring resistance to another, usually via a shared mechanism.
Cuticle: The insect's outer exoskeleton layer, including a waxy film that limits water loss.
Desiccant dust: A dust that destroys the cuticle's waterproofing so the insect loses water and dies — silica gel by sorbing the cuticle's lipids, diatomaceous earth by abrasion plus sorption. (Boric acid is not a desiccant; it is a stomach poison.)
Diamide: An insecticide class (IRAC Group 28) acting on the ryanodine receptor of muscle cells.
Eradication: Complete elimination of a pest population from a defined area — distinct from ongoing management.
Fumigant: A pesticide applied as a gas, which reaches pests in enclosed spaces and (for the structural fumigants) leaves no residual protection.
Harborage: A sheltered place where a pest rests, typically tight, dark, and near food and moisture.
IGR (insect growth regulator): A compound that disrupts development or reproduction rather than killing adults directly.
IPM: Integrated pest management: a decision framework prioritising prevention, monitoring, and least-risk controls.
IRAC group: The Insecticide Resistance Action Committee's mode-of-action classification number for an insecticide.
kdr: Knockdown resistance: target-site mutations in the sodium channel reducing pyrethroid sensitivity.
Knockdown: Rapid paralysis following insecticide exposure; knockdown is not the same as death, and recovery is possible.
Larva: The immature feeding stage in complete metamorphosis, between egg and pupa.
LD50: The dose lethal to 50% of test animals in a standard assay — an acute toxicity measure with real limits.
Metabolic resistance: Resistance via enhanced detoxification enzymes that break down an insecticide before it acts.
Metamorphosis: Developmental change between life stages; complete (four stages) or incomplete (three stages).
Mode of action: The biological mechanism by which a pesticide kills or disables its target.
Monitoring: Ongoing inspection or trapping to detect pests, identify species, and track population change.
Non-repellent: A treatment insects do not detect or avoid, allowing contact or social transfer before lethal effect.
Nymph: The immature stage in incomplete metamorphosis, resembling a small wingless adult.
Ootheca: A protective egg case, notably carried by German cockroaches until just before hatching.
Pheromone: A chemical signal used for communication within a species.
Pro-insecticide: A compound converted by the insect's own enzymes into its active, toxic form.
Pyrethroid: A synthetic insecticide modelled on natural pyrethrins, acting on voltage-gated sodium channels.
Repellency: Behavioural avoidance of a treated surface; can scatter social insects and complicate baiting.
Repellent (spatial): A substance that discourages insects from entering or landing in an area without necessarily killing them.
Reservoir: A host population in which a pathogen is maintained and from which transmission can occur; also, settled dust that retains allergen long after the pest is gone.
Secondary kill: Death of colony members that never contacted a bait directly, via social transfer of the active ingredient.
Secondary poisoning: Poisoning of a predator or scavenger that eats an animal poisoned by a pesticide — a documented concern with persistent second-generation rodenticides.
Signal word: The label word (CAUTION, WARNING, DANGER — or DANGER–POISON with a skull-and-crossbones for Category I acute systemic toxicity) indicating a product's acute toxicity category.
Spinosyn: A fermentation-derived insecticide class (IRAC Group 5) that modulates the nicotinic acetylcholine receptor at an allosteric site.
Synergist: A compound with little insecticidal action of its own that increases an insecticide's effect, typically by inhibiting the insect's detoxification enzymes (e.g. piperonyl butoxide).
Systemic: Distributed within a plant or animal's tissues after uptake, reaching pests that feed on those tissues.
Target site: The specific protein or structure an insecticide acts on, such as a sodium channel or receptor.
Thigmotaxis: Preference for contact with surfaces on multiple sides; explains cockroach harborage choice.
Trophallaxis: Social sharing of liquid food between colony members, exploited by slow-acting baits.
Vector: An organism that transmits a pathogen between hosts, such as a tick or mosquito.