Terms and Definitions

Abdomen – On insects, the third or last major body region which has spiracles on most segments.

Active ingredient – The component in a pesticide product which kills pests or affects pest behavior.

Adult – A sexually mature and fully grown arthropod which, in most species, is incapable of further growth.

Aerosols – Ready-to-use pesticide formulations which contain an active ingredient, solvent and propellant.

Allergy – A sensitivity reaction, which develops after an initial exposure to a proteinaceous substance.

Anaphylactic – A hypersensitivity reaction to proteins and other substances which, upon a second exposure, can cause life threatening conditions.

Antigen – a proteinaceous substance which causes an allergic reaction.

Antenna (-ae) – The paired segmented sensory structures on the head of an insect; located above the mouthparts and near the eye.

Anterior – In front; before; front.

Arthropod – An invertebrate animal which has a segmented body and jointed appendages; member of the phylum arthropoda.

Bacterium – Single-celled microorganisms which have no chlorophyll and which multiply by simple division. Some cause diseases and death in insects.

Bait – A pesticide formulation which contains water or food attractant and an active ingredient.

Capitate – A form of insect antenna which is expanded into a head at the tip.

Carton – In Formosan termites, the nest material composed of partially digested wood and soil cemented together with secretions and fecal material.

Caste – In social insects, a group of individuals which have a common functional characteristic, e.g., worker, soldier and reproductive.

Cephalothorax – Anterior body region in some arthropods in which the head and thorax are fused.

Cercus (cerci) – In some arthropods, a pair of segmented appendages located on the dorsal side and tip of the abdomen.

Chelicera (-ae) – The paired, typically fang-like anterior projections on many arachnids.

Chitin synthesis inhibitor – A chemical which affects the formation of the insect’s exoskeleton and causes death during the molting process.

Clavate – A form of insect antenna which is expanded into a club at the tip.

Cocoon – The silken covering over the pupa which is woven by the last instar larva.

Collophore – In springtails, the tube-like structure located on the underside of the first abdominal segment.

Commensal – Refers to rodents which live in close association with humans.

Complete metamorphosis – In insects, the developmental life cycle consisting of egg, several larval stages, pupa and adult.

Compound eye – This type of eye is composed of many individual cells, each having its own facet on the surface.

Coxa – The first leg segment attached to the ventral surface of the thorax.

Crochets – Small hook-like structures found on the underside of the prolegs on moth and butterfly larvae (caterpillars).

Cuticle – The thin three-layer outer surface of the exoskeleton.

Delusory parasitosis – An individual’s imaginary belief that their body is infested with insects.

Deutonymph – In ticks and mites, the second nymphal stage.

Dorsal – Back;upper side; top.

Dorsoventrally flattened – The space between the dorsal and ventral surfaces is narrower than the distance between the two sides; flat like a pancake.

Elytra – The first pair of wings typical of most beetles which are heavy, shield-like coverings.

Emulsifiable concentrate – A pesticide formulation composed of an active ingredient, solvent and emulsifier which readily dissolves in water.

Engorge – To fill with blood.

Entomology – The study of insects.

Entomophobia – Fear of insects.

Exoskeleton – The exterior shell or skeleton characteristic of the phylum arthropoda.

Facet – The external covering of a single element of the compound eye.

Femur – The third leg segment between the trochanter and the tibia.

Festoons – In many hard ticks, the rectangular areas on the posterior edge of the abdomen.

Filiform – A form of insect antenna which typically consists of many segments and is long and thread-like.

Fontanelle –  In some termites, a small pore on the front of the head.

Frass – Solid fecal material; wood fragments typically mixed with excrement produced by wood infesting insects.

Fumigant – A gas which, under proper conditions, readily penetrates all areas within a confined space and kills all life forms present.

Fungus – A plant which does not contain chlorophyll.

Furcula – In springtails, the fork-like structure attached to the tip of the abdomen.

Genal comb – In fleas, a row of very heavy spines projecting downward from the front part of the head.

Granules – A dry pesticide formulation consisting of particles, usually vermiculite, larger than those used for dusts, which are coated with an active ingredient.

Haltere – In flies (Diptera), the knob-like structure which aids in maintaining balance during flight and is attached to the metathorax in place of the second pair of wings.

Hastasetae – Spear-headed setae(hairs) usually found in clusters on dermestid beetle larvae.

Hypopharynx – In insect mouthparts, the tongue-like structure located in front of the labium and in the center of the other mouthparts.

Hypostome – In ticks, the tube located in the center of the mouthparts.

Inert ingredient – A component of a pesticide which aids in dissolving the active ingredient and facilitates its use.

Instar – The stage between molts.

Integrated Pest Management (IPM) – A decision-making process that anticipates and prevents pest activity and infestation by combining several strategies to achieve long-term solutions. Components of an IPM program may include proper waste management, structural repair, maintenance, biological and mechanical control techniques and pesticide application.

Labium – In insect mouthparts, the lower lip located behind the mouthparts.

Labrum – In insect mouthparts, the upper lip located above the mandibles.

Larva (-ae) – The developmental stages between the egg and pupa in insects with complete metamorphosis. In mites and ticks, the six-legged stage between the egg and nymph.

Larvicide – An insecticide which targets the larval stage of insects with complete metamorphosis.

Mandible – In insect mouthparts, the jaw.

Maxilla (-ae) – In insect mouthparts, the typically jaw-like structure which may have a palp; located behind the mandible.

Mesothorax – The second and middle segment of the insect thorax and the point of attachment for the second pair of legs and the first pair of wings.

Metamorphosis – The development and change an arthropod undergoes from the egg to adult.

Metathorax – The third and last segment of the insect thorax and the point of attachment for third pair of legs and second pair of wings.

Microencapsulated – A pesticide formulation which consists of a liquid or dry active ingredient surrounded by a plastic coating which gradually releases the active ingredient.

Naiad – The developmental stages between the egg and adult in aquatic insects with simple metamorphosis.

Nematodes – Unsegmented soil-inhabiting worms which are parasitic on plants and animals.

Nymph – The developmental stages between the egg and adult in terrestrial insects with simple metamorphosis. In ticks and mites, the eight-legged stage between the larva and adult.

Ocellus (-i) – A small, simple eye composed of a single facet or lens.

Ootheca (-ae) – The purse-shaped egg capsule common in cockroaches.

Ovipositor – In some insects, a long projection which extends from the tip of the abdomen and is used to lay eggs.

Parasite – An organism which lives in or on another organism from which it derives food and shelter.

Parthenogenic – Produces egg capsules without mating with males.

Pathogenic – The ability of a microorganism to cause disease.

Pedicel – The waist or small segment in ants and some bees and wasps; in ants, it is composed of one or two segments (nodes); in insects, the second antennal segment.

Pheromone – A chemical usually excreted outside the body and used for communication within a species.

Pincers – In some insects, the forceps-like structure at the tip of the abdomen.

Predator – An organism which captures, kills and eats its prey for food.

Pretarsus (i) – The sixth and last leg segment located after the tarsus and usually consisting of one or two claws and a pad-like structure.

Proboscis – In some arthropods, the long extension of the mouthparts used for sucking food; a beak.

Proleg – Paired abdominal processes used for locomotion by butterfly and moth larvae (caterpillars) and few other insect larvae.

Pronotal comb – In fleas, the stout spines located along the posterior margin of the first body segment behind the head.

Pronotum – The top or dorsal plate on the prothorax.

Prothorax – The first segment of the insect thorax.

Protonymph – In ticks and mites, the first nymphal stage.

Pupa (-ae) – The developmental stage between the larval and adult stages in insects with complete metamorphosis.

Pyrethrin – A natural insecticide derived from chrysanthemum plants which is irritating to many insect species and is used to flush them out of harborage areas; a toxicant.

Serrate – A saw-like form of insect antenna.

Simple metamorphosis – In insects, the developmental life cycle consisting of egg, several nymphal or naiad stages and adult.

Soluble powders – A dry pesticide formulation which dissolves in water to form a true solution.

Solutions – A liquid pesticide formulation which dissolves readily in water or petroleum based solvent.

Spiracle – The exterior opening of the respiratory system.

Stinger – A modified ovipositor which is used to inject venom.

Swarmer – In termites and ants, the winged reproductive stage which leaves the nest in mass to reproduce.

Synergist – A component frequently added to a pesticide product in order to enhance the activity of the active ingredient.

Tarsus (-i) – The fifth leg segment located between the tibia and the pretarsus; often composed of several segments.

Thorax – The middle section of the insect body which is composed of three segments – prothorax, mesothorax, and the metathorax; the point of attachment for the legs and wings.

Tibia – The fourth leg segment located between the femur and the tarsus.

Trochanter – In insect legs, the second segment located between the coxa and femur.

Wettable powder – A dry dust pesticide formulation designed for dispersal in water.