Non-selective chemicals, as the name suggests, control a wide range of pests. However, each non-selective chemical is unique-each controls certain types of pests and must be used in specific ways. The term "non-selective" is not completely accurate-in "real-world" use, no chemical provides perfect control of all its possible targets. Nevertheless, the chemicals we list here are some of the most powerful tools available for controlling pests.
As you'll see, most of these products are herbicides used for general, "non-crop" or industrial weed control. The exceptions are the soil fumigants, which, in the broadest sense, are the only true "non-selectives." These chemicals are pre-plant for a reason-they affect all organisms (or at least nearly so) in the treated soil: weeds, pathogens, insects, nematodes, etc. Obviously, such an application must not occur in an established planting.
Also available are non-selective contact herbicides such as diquat and pelargonic acid. These "burndown" productswork rapidly but leave roots and other untreated parts unaffected.
Systemic products (such as glyphosate), by contrast, translocate throughout the plant and kill roots as well as shoots, providing good control of perennial plants. However, they require several days or more before symptoms show. Glufosinate is a "hybrid," providing limited systemic movement, but delivering faster burndown and better control of woody and perennial weeds than contacts.
Many situations exist where you need "bare-ground" control: control you can obtain with soil-residual products (which may, in some cases, also be active through foliar uptake). These require great care and must not be used where the roots of desirable plants are growing. But for areas where you want no vegetation-and don't want to spend a lot of time re-treating-these chemicals are excellent tools.
This "Update" is for preliminary planning only. It is not a substitute for label instructions, which you must always read and follow whenever you use a pesticide. Remember that no product is ideal for all situations. Factors such as existing weeds, expense, safety to nearby desirable plants and application method will determine your choice.
Methyl bromide has been an important soil fumigant for many years. However, this product will soon be unavailable. In 1993, methyl bromide was scheduled for phase-out by 2001 under provisions of the Clean Air Act, which requires stringent controls of ozone-depleting chemicals.
However, Congress attached an amendment to its Fiscal Year 1999 appropriations bill to "harmonize" the U.S. phase-out with the Montreal Protocol. The Montreal Protocol is a treaty signed by more than 160 countries to reduce ozone-depleting chemicals worldwide. Its schedule consists of a stepped phase-out beginning with a 25-percent reduction in 1999 and culminating in a nearly complete end to methyl-bromide use by 2005. After that, only a few specific uses will be allowed. Thus, methyl bromide will be unavailable for nearly all of its current uses in the turf and ornamental industry, and, in most cases, no obvious replacement is available.
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