A chemical that is more toxic to some plant species than to others (may be a function of dosage or mode of application).
One that kills specific undesirable plants, sparing other desirable plants; this is done through different types of toxic action or by the manner in which the material is used (its formulation, dosage, timing, placement, etc.).
A chemical that kills plants in certain classes but not others. The contrasting term is "non-selective" herbicide, a chemical that kills all or nearly all plants.
a chemical or pesticide that controls either grasses or broadleaf plants.
Many herbicides are selective in what they control. That's why we can take broadleaf weeds out of your lawn or, control grasses in your flowerbeds. See also Non Selective Herbicide above.
One that can be applied to a mixed stand of turfgrass and weeds that will selectively kill certain weeds without injuring the turfgrasses.
a pesticide that kills only one type of plant, for example broadleaf herbicides only kill broadleaf weeds, not turfgrasses.