| A | |
| Abdomen | the posterior most of the three main body divisions of insects. |
| Abscission | the normal separation of fruit and leaves from plants by the development of a thin layer of pithy cells at the base of their stems. |
| Acaracide | a chemical used to control mites; also called a miticide. |
| Adeagus | the intromittent organ of a male insect; the penis. |
| Alate | having wings. |
| Analog | that which is similar or corresponds with something else; in chemistry, two compounds with similar compositions and structures. |
| Antenna | segmented sensory organs located on the head above the mouth parts. |
| Arachnid | any of a large class of arthropods that have four pairs of legs and breathe through lung-like sacs or breathing tubes. Some, such as mites, have bodies without exterior segmentation. Others, such as spiders, have bodies divided into two segments. Others have bodies of several segments. |
| Arrhenotoky | parthenogenesis in which only male offspring are produced. |
| Arthropod | any member of a large taxon of invertebrate animals with jointed legs and a segmented body; such as insects, crustaceans and arachnids. |
| Axil | the upper angle formed by a leaf and the stem from which it grows. |
| B | |
| Biofix | a biological fix point used to synchronize a degree-day model with insect development, such as the first capture of moths in a pheromone trap. |
| C | |
| Cambium | the layer of formative cells between the wood and bark in woody plants. The cells grow to form new wood and bark. |
| Chalcid wasp | a large family of very small wasps. In many cases the larvae are parasites on the eggs, larvae or pupae of other insects. |
| Clypeus | a shield-like plate on the anterior part of the head of certain insects. |
| Confidence interval (CI) | in statistics, the estimated mean, plus or minus a range within which one is confident that the true mean occurs. For instance, for a 95% confidence interval of 2.0 plus or minus 0.4, the estimate of the mean is 2, and if you were to repeat the experiment 100 times, in 95 of those experiments the estimated mean would fall between 1.6 and 2.4. |
| Cornicles | the protruding dorsal tubes on aphids that secrete a waxy substance. |
| D | |
| Deutonymph | third instar of an immature tetranychid mite |
| Diapause | a period of delayed development or growth accompanied by reduced metabolism and inactivity. |
| Dorsal | pertaining to the back or upper side of the body. |
| E | |
| Ecdysis | the process of shedding the old skin (cuticle). |
| Ecdysone | (molting or prothoracic hormone) a hormone produced in the prothoracic gland that initiates growth and molting activities of the epidermal cells. |
| Eclosion | the act of the insect leaving the egg or emergence of the adult at the terminal molt. |
| Ecosystem | a system made up of a community of animals, plants and bacteria, and its interrelated physical and chemical environment. |
| Ectoparasitoid | a parasitoid that lives on the outside of its host. |
| Elytra (plural of elytron) | the front pair of thickened wings in beetles, which form a protective covering for the rear wings. |
| Endoparasitoid | a parasitoid that lives inside its host. |
| Epidermis | the outer layer of skin of an insect, or the outermost layer of cells of a plant. |
| Exoskeleton | the hard, external, secreted supporting structure of an insect; an external skeleton. |
| Exuvia | the cast skin of an arthropod. |
| F | |
| Fecundity | the rate at which a female produces eggs. |
| Filiform | thread-like. |
| Flagging | wilting of foliage. |
| Frass | refuse or excrement left by insect larvae. |
| G | |
| Gaster | the abdomen of Hymenoptera; also, the final 7-8 segments of the abdomen of an ant, just behind the petiole. |
| Generation | a group of offspring from a parent population moving through a life cycle together. |
| Genus (plural, genera) | a classification of insects with common characteristics; the main subdivision of a family; made up of a group of closely related species or of a single species. |
| Gummosis | the giving off of gummy substances as a result of cell degeneration. |
| H | |
| Head | the anterior (front) most part of the three main body segments of insects which contains the antennae, eyes, mouth parts and brain. |
| Hibernaculum (plural, hibernacula) | a case or covering for protection during the winter. |
| Honeydew | the liquid excrement of certain phloem-feeding insects, such as aphids, mealybugs, and pear psylla. It is composed of water, plant sugars and amino acids. |
| Host | an organism on or in which another (called a parasite) lives for nourishment or protection. |
| I | |
| Induced pest | an insect or mite raised to pest status by destruction of natural enemies. |
| Insect | class of Arthropoda that is characterized by three body divisions, three pairs of thoracic legs, and one pair of antennae. |
| Instar | a stage of an insect between molts; a growth stage. |
| J | |
| Juvenile hormone | hormone produced by the corpora allata and serves several functions including suppression of adult characters. |
| K | |
| Key pest | pest around which management programs are built. Examples are codling moth, oriental fruit moth and cherry fruit fly. |
| L | |
| Lamella (plural, lamellae) | a series of overlapping plate-like structures used to refer to the type of antennal club in some beetles. |
| Larva (plural, larvae) | a comprehensive term for the immature stages of insects with complete metamorphosis (e.g.; flies, beetles, moths, wasps). Often specific names are given to the larvae of some orders or families fly larvae are called maggots, scarab beetle larvae are called grubs. |
| Lateral | pertaining to the side of the body. |
| Life cycle | the sequence of events and stages that occurs in the life of an organism. |
| Life history | the sequence of events that occur during an annual cycle including the habitat setting where they occur |
| M | |
| Margin | edge. |
| Mesophyll | the soft green tissue inside a leaf between the lower and upper epidermis, chiefly concerned in photosynthesis. |
| Metamorphosis | the series of changes from the egg to the adult stage whereby insects grow and develop. Metamorphosis is said to be complete when the pupa is inactive or does not feed, and incomplete when the pupal stage is lacking, or is active and feeds. |
| Micron | one thousandth of a millimeter, one millionth of a meter. |
| Mine | a hollow made by an insect under the surface of a leaf. |
| Molt | the process by which insects shed their outer skin (exoskeleton), in order to increase in size. |
| Morphology | the branch of biology that deals with the form and structure of animals and plants. |
| Mycelium | the vegetative part of a fungus, made of a mass or network of thread-like tubes. |
| N | |
| Neurotoxin | a poison that interferes with nerve function. |
| Nymph | a comprehensive term for the immature stages of insects with incomplete metamorphosis (e.g.; true bugs, aphids, leafhoppers and grasshoppers). |
| O | |
| Operculum | a lid-like structure, usually over an egg. |
| Ovate | shaped like the longitudinal section of an egg. |
| Ovicide | an insecticide effective on the egg stage. |
| Ovipositor | an organ of many female insects for depositing of eggs, often in a host. |
| P | |
| Parasite | an organism that lives on or in one of another species, from which it derives sustenance or protection. It usually does not benefit the host, and often does it harm. It may complete its life cycle without killing the host. |
| Parthenogenesis | asexual reproduction by means of the development of an unfertilized egg. for example, in aphids a number of parthenogenetically produced generations succeed a sexually produced generation. Finally, males are produced (also by parthenogenesis) and sexual reproduction again occurs. |
| Pest | an organism that interferes with human activities, property or health, or is objectionable. |
| Petiole | in a plant, the stalk of a flower cluster or leaf; in an insect, the slender, stalk-like part between the thorax and abdomen of the body. |
| Phenology | the study of the effects of climate on recurring natural phenomena, such as insect or plant development. |
| Phenology model | a model based on accumulated heat units used to predict significant events in the life cycle of a plant or insect (e.g.; full bloom, egg hatch). |
| Pheromone | a chemical substance secreted by an insect to convey information to others of the same species. |
| Phylum | a principal division of the animal kingdom. |
| Physiology | science of the functions and phenomena of living organisms and their parts. |
| Phytophagous | herbivorous, or plant-feeding. |
| Predator | an organism that lives by capturing and feeding upon another. Unlike parasitoids, predators consume many hosts during their development. |
| Prolegs | the stubby limbs on the abdomen of the larvae of Lepidoptera, sawflies and some other insects. |
| Prothorax | the first segment of the thorax of insects, bearing the first pair of legs. |
| Protonymph | second instar of an immature mite. |
| Pupa | stage between the larva and adult of an insect with complete metamorphosis. |
| R | |
| Race | a population that differs from others in the relative frequency of some gene or genes. |
| Recurrent vein | small veins running transversely between major veins on the wings of Hymenoptera. |
| Refugium (plural, refugia) | a small, isolated area that has escaped changes undergone by the surrounding area. |
| S | |
| Scutellum | a feature on the dorsum of an insect, made up of one or more of the thoracic segments a prominent feature of Hemiptera (true bugs), where it is a triangular-shaped part of the middle thoracic segment enclosing the angle of the forewings at rest. |
| Secondary pest | a pest that is less important than a key or primary pest. Examples are aphids, mites and leafhoppers. |
| Selection | a process by which certain organisms or characters are favored or perpetuated in preference to others. |
| Seta (plural setae) | a bristle or bristle-like part or organ. |
| Species | the basic unit of classification of living organisms. A class of similar insects that generally interbreed only among themselves; a subdivision of a genus. |
| Spermatophore | a case or capsule containing a number of spermatozoa, expelled whole by the male of certain animals, including rust mites. |
| Spiracle | a breathing pore; an external opening of the tracheal system. |
| Stage | an insect’s developmental status (e.g.; egg stage). |
| Stipe | a usually short, thick stem such as found on certain mite eggs. |
| Stoma (plural, stomata) | minute holes in leaves through which trees exchange gases. |
| T | |
| Taxonomy | the system of arranging animals and plants into natural, related groups based on some factor common to each. The basic taxonomic categories are, in descending order Kingdom, Phylum, Class, Order, Family, Genus, and species. |
| Thoracic shield | the dorsal plate of the prothorax; a plate on the insect’s upper side just behind the head. |
| Thorax | the middle of the three main divisions of the insect’s body; the body part between the head and abdomen that bears the legs and wings. |
| Trachea | a tube of the respiratory system that begins with a spiracle and ends with the tracheoles. |
| Tubercle | a small, rounded projection. |
| V | |
| Ventral | underside of the body. |
