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Weed Control Glossary
| A | B | C | D | E | F | H | N | P | R | S | T | Acid Equivalent ( abbreviation - a.e.) (2,4-D, glyphosate) - the active part of the acid herbicide being used - usually indicated in grams/L on the label. Active Ingredient - the chemical in a formulated product that is responsible for the herbicide effects. Adjuvant - an ingredient added to a herbicide formulation or spray mixture to aid or modify the action of the herbicide, or the physical characteristics of the mixture. Amine - acid or anionic herbicides can be formulated as ammonium salts or amines. 2,4-D amines are relatively non-volatile under most climatic conditions. Annual Plant - completes its life cycle within a one year period.. Summer annuals complete their life cycle between spring and fall. Winter annuals germinate in fall, overwinter and then flower and complete their life cycle the following spring or summer. | Top of Page | Band Treatment - a herbicide applied as a narrow strip over the crop row, usually followed by inter-row cultivation. Biennial Plant - completes its life cycle within a two-year period. Germinates in the spring, overwinters, flowers the following spring or summer and dies back the following fall. | Top of Page | Carrier - the diluent or material added to a herbicide product to facilitate its even distribution over the target area. The carrier is often water but it may also be granular products, oil or other solvents. Compatible - compounds or formulations that can be mixed and applied together without undesirably altering their separate effects effects or the physical properties of the mixture. Contact Chemicals - chemicals that kill only the parts of the plant on which they are sprayed. Movement within the plant is minimal. Cotyledons - the seed leaves. Often visible when large seeds are opened. These are the first leaves visible in the germinated seedling. Broad-leaved crops or weeds have two cotyledons(dicots). Grasses (monocots) have one. | Top of Page | Directed Treatment - a treatment directed onto the weeds or soil in such a manner as to avoid contact with the crop. Dormant - a resting stage similar to the condition of a plant during the winter. | Top of Page | Emergence - the time at which the seedling first appears above the ground. Escape - a plant in a treated area that has been missed or survived the treatment. Ester - Some acid herbicides are reacted with alcohols to produce ester formulations. Ester formulations of 2,4-D and related herbicides can vaporize under hot conditions after treatment and cause unwanted damage by moving away from the treated area. | Top of Page | Formulation - means the same as Product - an active ingredient processed with other materials or formulants to make it easier to apply and/or more effective. Herbicides are rarely sold as pure active ingredients (2,4-D acid), they are sold as formulated mixtures (i.e. 2,4-D amine, sodium salt or ester with added emulsifiers, adjuvants, carriers, etc.). | Top of Page | Half-life - the time required for 50% of a herbicide to be degraded or inactivated in soil or water. Herbicide - a chemical that is toxic to plants. Herbicide Tolerant Crops (abbreviation - HTCs) - New varieties of crops that have been developed by classical breeding or transgenic techniques to be tolerant to specific herbicides Hormone-Type Herbicide - includes 2,4-D, 2,4-DB, mecoprop, MCPA, MCPB, dichlorprop, dicamba, triclopyr, and picloram. At extremely low concentrations, these chemicals can stimulate and/or disrupt the growth of broadleaved plants. | Top of Page | Non-Selective Herbicide - a chemical used in such a manner that all exposed vegetation is damaged. | Top of Page | Perennial Plant - lives for more than 2 years. Product - the contents of a herbicide container as marketed.
In addition to the active ingredient, it may also contain other solvents,
surfactants or carriers that are referred to as inert ingredients or formulants. | Top of Page | Resistant Weeds (Herbicide Resistant Weeds) - the inherited ability of some weeds in the population of a particular weed species to survive a herbicide application to which most of the original population was susceptible. | Top of Page | Selective Herbicide - a chemical used in such a manner that it will kill weeds on a growing crop without damaging the crop. Sodium Salt - some acid or anionic herbicides can be formulated as sodium salts (e.g. 2,4-D). Soil Sterilant - a soil active herbicide that is applied at a sufficiently high rate to prevent all plant growth for at least one season Surfactant - a chemical added to the herbicide formulation or to the spray solution to improve the dispersing, spreading, sticking or wetting properties of the spray mixture. Susceptible - a crop that may be damaged or a weed that may be readily controlled by a recommended rate of herbicide. | Top of Page | Tank Mix - two chemicals that are packaged separately and mixed in the sprayer tank. Translocated Herbicide - a chemical herbicide that moves within the plant. | Top of Page | Related Links
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Excerpt
from 2008 Publication 75, Guide to Weed Control,