AFM 91-19 / TM 5-629 / NAVFAC MO-314
24 May 1989
Submersed plant -- An aquatic plant that grows
restrictive sense to refer to herbicides that are
with all or most of its vegetative tissue below the
applied to the foliage and move downward
through the phloem to underground parts.
Surfactant -- A material which improves the
emulsifying, dispersing, spreading, wetting, or
Vapor drift -- The movement of chemical vapors
other surface-modifying properties of liquids.
from the area of application, Some herbicides,
Susceptibility -- The sensitivity to, or degree to
when applied at normal rates and normal tem-
which a plant is injured by, a herbicide treat-
peratures, have a sufficiently high vapor pres-
ment. (See tolerance.)
sure to change them into a vapor that may cause
Suspension -- A mixture containing finely divided
injury to susceptible plants distant from the site
particles evenly dispersed in a liquid.
of application. NOTE: Vapor injury and injury
Systemic herbicide -- Synonymous with transloca-
from spray drift are often difficult to distin-
ted herbicide, but more often used to describe
the action of insecticides or fungicides.
Volatile -- Capable of being readily vaporized.
Tank-mix combination -- Mixing of two or more
Weed -- Any plant that is objectionable or that
pesticides or agricultural chemicals in the spray
interferes with the activities or welfare of man.
tank at the time of application.
Weed control -- The process of reducing weed
Tolerance -- (1) Ability to withstand herbicide
growth or infestation to an acceptable level.
treatment without marked deviation from nor-
Weed eradication -- The elimination of all live
mal growth or function. (See susceptibility.)
plant parts and viable seeds of a weed from a
(2) The concentration of herbicide residue that
will be allowed in or on agricultural products.
Wetting agent -- (l) A substance that reduces
Toxicity -- The quality or potential of a sub-
interfacial tensions and causes spray solutions or
stance to cause injury or illness.
suspensions to make better contact with treated
surfaces. (See surfactant.) (2) A substance in a
Toxicology -- The study of the principles or
wettable powder formulation that causes it to
mechanisms of toxicity.
wet readily when added to water.
Teratogenic -- Capable of producing birth de-
Wettable powder (wp) -- A finely divided dry
formulation that can be readily suspended in
Trade name -- A trademark applied to a herbi-
cide formulation by its manufacturer.
Translocated herbicide -- A herbicide that is
Xylem -- The nonliving tissue in plants that func-
moved within the plant. Translocated herbicides
tions primarily to conduct water and mineral
may be either phloem-mobile or xylem-mobile,
nutrients from roots to the shoot.
but the term is frequently used in a more