Terms and Glossary

ACTIVE INGREDIENT (ai):  The chemical or chemicals in a formulated product principally responsible for the herbicidal effects, and that are shown as active ingredients on herbicide labels.

ANNUAL:  A plant that completes its life cycle from seed in one year.

AQUATIC PLANTS: Plants that grow in water or water-saturated soil.  There are three types: submergent plants grow beneath the surface; emergent plants have roots below the surface and leaves and stems above the water; and floating plants.

BAND OR ROW APPLICATION: An application to a continuous restricted area such as in or along a crop row rather than over the entire field. 

BASAL TREATMENT:  A treatment applied to the stems of woody plants at and just above the ground.

BENEFICIAL INSECT: An insect that is useful or helpful to humans.  Examples are pollinators, parasites, and predators of pests.

BIENNIAL: A plant that completes its life cycle in two years.  The first year the seed germinates and the plant produces leaves, roots, and stores food.  The second year it flowers and produces fruits and seeds.

BIOLOGICAL CONTROL:  Controlling a pest with existing or introduced natural enemies; these may already occur in the area or be introduced.

BROADCAST APPLICATION:  A uniform application over an entire area.

BROADLEAF PLANTS:  Botanically classified as dicotyledons.  Plants have two cotyledon leaves in the seedling stage; true leaves are usually broad and have netlike or reticulate veins.

BRUSH CONTROL:  Control of woody plants.

CHEMICAL CONTROL:  A pest management strategy that involves the use of naturally derived or synthetic chemicals that kill, or otherwise control the growth of pest plants.

CONTACT HERBICIDE:  An herbicide that is phytotoxic or kills by contact with plant tissue rather than as a result of translocation.


CONTROL:  In general, reduction of the weed problem to a point where it does not cause economic damage.  According to the noxious weed law, the prevention of seed production.

CULTURAL CONTROL: A pest management strategy that involves the manipulation of the environment to avert serious pest damage.  Examples are crop rotation, soil tilling, pruning, etc.

DICOTYLEDON (DICOT):  A plant that has two seed leaves or cotyledons; broadleaf plants.

DIRECTED APPLICATION:  Precise application to a specific area or plant part such as to a row, or bed, or to the lower leaves and stems of plants.

EMERGENCE:  The act of germinating seedlings breaking through the soil surface.

ENVIRONMENT: All the features that surround and affect an organism or group of organisms.

EPA: The Environmental Protection Agency is the federal agency responsible for implementing pesticide rules and regulations and registering pesticides.

ERADICATION:  The elimination of all live plant parts and seeds of a weed from a site.

FOLIAR APPLICATION: Application of an herbicide to plant leaves or foliage.

GERMINATION: The process whereby seeds or spores sprout and begin to grow.

GRASS:  Botanically, any plant of the Poaceae family.  Grasses are characterized by narrow leaves with parallel veins; by leaves composed of blade, sheath and ligule; by jointed stems and fibrous roots; and by inconspicuous flowers usually arranged in spikelets.

HERBACEOUS PLANT: A vascular plant that does not develop persistent woody tissue aboveground.

HERBICIDE:  A chemical used to kill plants or severely interrupt their normal growth processes.

INCORPORATE INTO SOIL: Mixing an herbicide into the soil, generally by mechanical means.


INTEGRATED PEST MANAGEMENT:  Includes the use of all suitable methods for pest control, with pesticides used only when necessary and at appropriate rates. Methods include prevention, cultural, mechanical, biological, and chemical. 

MECHANICAL CONTROL:  A pest management strategy that uses physical and mechanical weed control methods to prevent the spread or reduce a weed infestation, such as digging, hoeing, pulling, etc.

MONOCOTYLEDON (MONOCOT):  A seed plant having a single cotyledon or leaf; includes grasses, sedges, and lilies.

NONSELECTIVE HERBICIDE:  A chemical that is generally toxic to plants without regard to species (may be a function of dosage, method of application, etc.)

NOXIOUS WEED:  A weed specified by law as being especially undesirable, troublesome, and difficult to control.

PERENNIAL: A plant that lives for more than two years.

PEST: An undesirable organism (e.g., weed, insect, fungus, etc.) that is injurious to humans, desirable plants, animals, or the environment.

PESTICIDE: Any substance or mixture of substances that controls or kills weeds, fungi, insects, rodents, and other pests.

POSTEMERGENCE: Timing: After emergence of the specified weed or plant.

P.P.E:  Personal Protective clothing and Equipment, which are intended to protect a person from exposure during the handling and application of pesticides.  P.P.E. includes long-sleeved shirts, long trousers, coveralls, hats, gloves, shoes and respirators where appropriate.

PREMERGENCE: Timing: Before the emergence of the specified weed or plant.

PREPLANT APPLICATION: Timing: Added to the soil or weeds before seeding or transporting.

PUBLIC CONSULTANT: A type of certification or license for a government agency or utility company employee who offers technical advice or recommendations for pesticide use (other than home or gardens) during the course of their employment.

PUBLIC OPERATOR: A type of applicator certification or license for a government agency or utility company employee who supervises or applies restricted use pesticides by any means, or applies general-use pesticides by power equipment.


REGISTERED: Pesticides approved for use in Washington by the Environmental Protection Agency and the Washington State Department of Agriculture.

RHIZOME: Underground root-like stem that produces roots and leafy shoots.

ROSETTE: Basal or early leaves of a plant, before bolting.

SEEDLING STAGE:  Early stage of plant growth, within a few days to a few weeks after seed germination and emergence.

SELECTIVE HERBICIDE: A chemical toxic to some plant species and not to others (may be a function of dosage or mode of application).

SOIL APPLICATION:  Applied primarily to the soil surface rather than to vegetation.

SPOT TREATMENT:  Targeted application to small areas.

STOLON: Above-ground runners or slender stems that develop roots, shoots, and new plants at the tips or nodes.

SUPPRESSION: The reduction of a weed population, but not elimination.

SYSTEMIC: A compound that moves freely within a plant; application to one area results in movement to all plant areas (translocation).

TRANSLOCATED HERBICIDE:  An herbicide that is able to move throughout a plant after being applied to leaf surfaces (translocated)

TRANSLOCATION:  Transfer of sugars or other materials such as 2, 4-D, from one part of a plant to another (see Systemic).

WEED:   Any plant growing where it is not desired, that is a nuisance, hazard, or causes injury to humans, animals, or crops.