Glossary

Penetration of a substance from the surface to below the surface.

The acid portion of the active ingredient. Rates of acid-based herbicides (2,4-D, dicamba, glyphosate, dalapon, picloram) should be expressed as acid equivalents per unit area.

A material used to absorb poisons in the stomach. Also used to bind herbicides at time of application, such as carbon banding along the seed row.

The chemical in a formulated product responsible for herbicidal effects.

Dosage required to kill 50% of test animals given a single oral dose in toxicity studies.

The amount of a substance, as a single dose, to cause poisoning in a test animal.

Any substance in a herbicide formulation that enhances the effectiveness of the herbicide.

Adherence of a substance to a surface.

To mix continuously.

A surface-active additive to a herbicide having a negative charge. Not commonly used with herbicides.

A plant that completes its life cycle in 1 year; i.e., germinates from seed, produces seed, and dies in the same season. Examples include pigweed, ragweed, mustard, foxtail, and crabgrass. A winter annual is one that germinates in the fall, lives over winter, then flowers and seeds the following spring and summer. Pennyroyal, hedge mustard, and peppergrass are winter annuals. (Also see Winter Annual.)

Opposing action of different chemicals such that the action of one is impaired or the total effect is less than that of one component used separately.

A first-aid treatment to counteract poisoning.

A plant that grows in water. The three kinds are: Submergent grows beneath the surface; Emergent grows above the water (cattails and water lilies); and Floaters such as water hyacinth.

An application to a continuous restricted area, such as in, on, or along a crop row rather than over the entire field.

An application to the stems of plants at and just above ground line.

Narrow shelf, typically along the water's edge of canals formed by deposited silt.

A plant that completes its life cycle in 2 years. The first year it produces leaves and stores food. The second year it blossoms and produces fruits and seeds. Examples include wild carrot, common mullein, bull thistle, and burdock.

The qualitative or quantitative determination of the presence of a substance by response measurements of treated living organisms, as compared to measurements on the same untreated, check, or standard living organism.

An application of spray over an entire area or field rather than only on rows, beds, middles, or individual plants.

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

A substance capable of producing cancer.

A gas, liquid, or solid substance used to dilute, propel, or suspend a herbicide to facilitate its preparation, storage, shipment, or use. (See also Diluent.)

Loss of green color in foliage followed by yellowing on the tissue.

Results produced in test animals exposed for long periods to chemicals.

Two compounds or products that can be mixed without affecting each other's performance.

The amount of active ingredient or herbicide in a quantity of diluent, expressed as percentage or as pounds per gallon (lb/gal), etc.

A herbicide that is phytotoxic by contact with plant tissue rather than as a result of translocation. Only that portion of a plant contacted is directly affected. Young seedlings are killed, but perennials may recover because of the uninjured parts below ground.

An application made after weeds emerge but before crop emerges.

The practice of growing different crops in succession on the same land, chiefly to preserve the productive capacity of the soil.

Resistant plants that are resistant to other herbicides with the same site of action.

Conservation Reserve Program.

Treatments applied to frills or girdles that have been made through the bark into the wood of the tree.

Waxy, fatty material that covers plant surfaces such as leaves.

Plants that are perennial in habit but lose their leaves during winter.

A material that causes the leaves to fall from plants.

The process by which a chemical is decomposed or broken down into less complex compounds or elements.

Depletion of oxygen.

Measures the amount of a pesticide or poisonous material that can be absorbed through the skin of animals to produce toxic symptoms.

Any substance or mixture of substances used to accelerate the drying of plant tissue. Foliage often is killed by contact action and seed moisture is reduced.