April 19, 2018

Appendix B: Glossary of Terms

Abdomen: The third (posterior) major division (tagma) of an insect body.

Acervulus (pl. acervuli): A mass of closely clustered conidiophores and conidia not covered by fungal tissue, initially subcuticular or subepidermal but eventually exposed.

Action threshold: The pest density at which a control tactic is implemented (an action is taken).

Active ingredient (AI): The component of a pesticide formulation responsible for the toxic effect.

Alate: Winged; having wings.

Alkaloids: Substances found in plants, many having powerful pharmacologic action, and characterized by content of nitrogen and the property of combining with acids to form ‘salts’.

Allelochemical: A chemical functioning in interspecific communication.

Apterous: Wingless. 

Ascospore: A spore borne in an ascus.

Ascus: A cell that is the site of meiosis and in which endogenous spores are formed.

Asexual: Reproduction typically associated with unicellular organisms like bacteria where reproduction is by way of division or budding.

Augmentation: Biological control practices intended to increase the number or effectiveness of it.

Bacterium: A single-celled microscopic plant-like organism that does not produce chlorophyll.

Beneficial Insect: Beneficial Insects are any of a number of species of insects that perform valued services like pollination and pest control.

Biological control: The use of living organisms, such as predators, parasitoids, and pathogens, to control pest insects, weeds, or diseases. Typically involves some human activity.

Brood: A clutch of individuals that hatch at the same time from eggs produced by one set of parents.

Canker: A term used for a plant disease characterized (in woody plants) by the death of cambium tissue and resulting loss and/or malformation of bark, or (in non-woody plants) by the formation of sharply delineated, dry, necrotic, localized lesions on the stem. The term "canker" may also be used to refer to the lesion itself, particularly in woody plants.

Caterpillar: The immature stage (larva) of a butterfly, moth, or sawfly.

Chlorosis: A yellowing, whitening, or paling of plant parts which are normally green, such as interveinal chlorosis which takes pace between leaf veins.  Caused by a lack of chlorophyll, the root cause can be insect, disease, or nutrient related.

Cocoon: A silken case formed by an insect larva for pupation.

Conidiophore: A hypha, often specialized in structure, that bears one or more conidia.

Conidium (pl. conidia): A thin-walled, asexual spore that is borne exogenously on a conidiophore and is deciduous at maturity.

Cultivar: A contraction of "cultivated variety" (abbreviated to cv); a group (or one among such a group) of cultivated plants clearly distinguished by one or more characteristics and which retains these characteristics when propagated; a distinct variety or race of plants that originated under cultivation and persists under cultivation. A cultivar may or may not be referable to a botanical species. Cultivars are given a name, usually distinguished by the use of single quotation marks.

Cultural control: Pest management practices that rely upon manipulation of the cropping environment (e.g., cultivation of weeds harboring insect pests).

Diapause: A physiological state of arrested metabolism, growth, and development that occurs at a particular stage in the life cycle of an organism.

Dormancy: A recurring period in the life cycle of an organism when growth, development, and reproduction are suppressed.

Ecdysis: Splitting and casting off of the old cuticle, the major event in molting.

Economic Damage: The amount of injury which will justify the cost of artificial control measures.

Economic Injury Level (EIL): The lowest level of a pest that will cause economic damage (ie,. the level of pests where the dollar loss caused by the pest exceed the cost of control).

Economic Threshold (ET): The level of pest infestation when control should be applied to keep an increasing pest population from causing economical losses. The ET is also called the action threshold because it is the pest level where action should be taken so that economic losses are avoided.

Elytra: Hardened forewings that protect membranous hindwings; characteristic of beetles.

Family: A taxonomic subdivision of an order, containing a group of related genera. Family names end in "idae".

Flagellum (pl. flagella): A whip-like appendage responsible for motility in the majority of motile bacteria and other protists, fungi, algae.

Forewings: The anterior pair of wings, usually on the mesothorax.

Frass : Excreta of an insect, particularly a larva.

Fungicide: Any substance that kills or inhibits the growth of a fungus.

Fungus, Fungi (pl.): Any of numerous plants lacking chlorophyll, ranging in form from a single cell to a body of branched filaments. Includes the yeasts, molds, smuts, and mushrooms.

Gall: An aberrant plant growth produced in response to the activities of another organism, often an insect.

Generalist: A pest or natural enemy that can utilize a wide range of species as host or prey.

Generation: Period from any given stage
in the life cycle to the same life stage in the offspring. Typically from egg to egg.

Girdle: Damage that completely encircles a stem or root, often resulting in death of plant parts above or below the girdle.

Gregarious: Forming aggregations.

Grub: A scarabaeiform larva, i.e. a thick bodied larva with thoracic legs and well developed head; usually sluggish.

Hemimetabolous: Having incomplete metamorphosis.  Insect undergoes gradual change from molt to molt, with externally developing wing pads.

Holometabolous: Having complete metamorphosis, passing through egg, larval, pupal, and adult stages.

Herbicide: A substance used to kill or control weeds.

Hind wings: The wings on the metathoracic segment.

Hypha (pl. hyphae): Filamentous part of a fungus, usually septate and consisting of several cells in linear succession.

Indirect pest: A pest insect that feeds on a part of the plant that is not marketed.

Insect: An an arthropod with 6 legs and 3 main body sections: a head, thorax, and an abdomen.

Insecticide: Any substance that kills or inhibits the growth of an insect.

Instar: The immature growth stages of insects between two successive molts.

Integrated pest management (IPM): IPM is a science-based, decision-making process that manages pests through the use of multiple control tactics in a manner that is environmentally responsible, socially acceptable and also economically practical.

Inundative: The release of large numbers of a natural enemy such that their population completely overwhelms that of the pest.

Invertebrate: An animal having no internal skeleton.

Laccase: A copper-containing enzyme that carries out one-electron oxidation of phenolic and related compounds, and reduces O2 to water.

Larva (pl. larvae): Immature stage of insects with complete metamorphosis.

Lesion: A localized area of diseased or damaged tissue.

Metamorphosis : Change in body form between the end of maturity development and the onset of the adult phase.

Molting: The formation of new cuticle followed by ecdysis.

Moth: Insects in the order Lepidoptera that can be distinguished from butterflies by their nocturnal activity, hairlike or feathery antennae, stout bodies, and the frenulum that holds the front and back wings together.

Mummy: A dried, shrivelled fruit colonized by a fungus.

Mycelium (pl. mycelia): A mass of hyphae, often used to denote all hyphae comprising a thallus.

Mycoplasma: A member of the genus Mycoplasma. Mycoplasmas, unlike viruses, can reproduce in the absence of a host and are the smallest free-living organisms; they have a unit membrane but no cell wall as do bacteria.

Natural enemies: Predators, parasites, or pathogens that are considered beneficial because they attack and kill organisms that we normally consider to be pests.

Necrosis: Death of tissue accompanied by dark brown discoloration, usually occurring in a well-defined part of a plant, such as the portion of a leaf between leaf veins or the xylem or phloem in a stem.

Nymph: An immature insect after emerging from the egg, usually restricted to insects in which there is incomplete metamorphosis (hemimetabolous).

Oospore: A thick-walled spore that develops from an oosphere.

Order: A taxonomic subdivision that contains groups of related families or superfamilies; usually ending in -ptera in insects.

Overwinter: A period of rest or hibernation by which insects survive the winter.

Oviposition: The laying or depositing of eggs.

Ovipositor: The egg-laying apparatus of a female insect.

Parasite: An organism that lives in or on another organism (the host) during some portion of its life cycle.

Parasitoid: An animal that feeds in or on another living animal, consuming all or most of its tissues and eventually killing it.

Pathogen: A disease-causing organism.

Pedicil: The stalk of a flower or fruit when in a cluster or when solitary.

Pest: An insect, weed, plant pathogen or vertebrate that reduces crop yields, negatively impacts animal or human health or causes structural damage.

Pest resurgence: The rapid rebound of a pest population after it has been controlled.

Pheromone: A chemical used in communication between individuals of the same species, releasing a specific behavior or development in the receiver.

Polyphagous: Feeding on a broad array of plant or animal species.

Predator: An organism that eats more than one other organism during its life.

Proleg: An unsegmented leg of a larva.

Pronotum: The upper (dorsal) plate of the prothorax.

Prothorax: The first segment of the thorax.

Pupa (pl. pupae): The inactive stage between larva and adult in holometabolous insects; also termed a chrysalis in butterflies.

Pycnidium (pl. pycnidia): A rounded or flask-shaped asexual fruiting body containing spores found in certain fungi.

Rachis: The main stalk of a flower cluster or the main leafstalk of a compound leaf.

Random sample: A sampling plan in which locations for samples are not predetermined either by previous sampling in that field or the relationship of one sample site to another.

Reflex Bleeding: A behavior involving the release of hemolymph from the legs of lady beetles. Occurs when lady beetles are stressed.

Sampling: Estimating the density of organisms (pests or natural enemies) or damage by examining a defined portion of the crop.

Saprophyte: An organism that obtains its nutrients from non-living organic matter (commonly dead and decaying plant or animal matter) by absorbing soluble organic compounds. (now known as saprotroph)

Scouting: See Sampling.

Seta (pl. setae): Hair: a sclerotized hairlike projection.

Secondary pest: An insect that does not normally attain pest status except when insecticides destroy its natural enemies.

Sensory Threshold: The minimum level of stimulus required to initiate (release) a response.

Sclerotium (pl. sclerotia): Hard, resistant, multicellular resting body, usually with a differentiated cortex and medulla, that under favorable conditions can germinate to produce mycelium or sexual or asexual fruiting bodies.

Species: A group of like individuals that can interbreed, mainly within the group (sharing a gene pool) and producing fertile offspring, usually similar in appearance and behavior.

Sporangiophore: A modified hypha that supports the sporangium.

Sporangium (pl. sporangia): A sac that bears endogenous, asexual spores (sporangiospores).

Spore: A discrete sexual or asexual reproductive unit, usually enclosed by a rigid wall, capable of being disseminated.

Systemic insecticide: An insecticide that is absorbed into plant sap and is lethal to insects feeding on or within the treated plant.

Thallus: Any simple vegetative plant body that lacks roots, stems and leaves.

Thorax. The middle of the three major divisions of the insect body. The legs and wings (if present) are always attached to the thorax.

Threshold: The point that must be exceeded to elicit a response (see Economic Threshold)

Trap crop: A small area of a crop used to divert pests from a larger area of the same or another crop. The pests, once diverted to the trap crop, may be treated with an insecticide.

Variety: An identifiable strain within a species, usually referring to a strain which arises in nature as opposed to a cultivar which is specifically bred for particular properties; sometimes used synonymously with cultivar.

Véraison: Beginning of fruit ripening, recognized by berry softening and beginning of pigmentation in colored varieties.

Worker: In social insects, a member of the sterile caste that assists the reproductive individuals.

Zoospore: An asexual, motile spore that bears one or two flagella.