Herbicides granular

Paraquat and diquat are dipyridyl herbicides used for weed control and as preharvest (desiccant) defoliants. Paraquat has been used for large-scale control of illegal marijuana growing. Dipyridyl product fonnulations differ by country. In the United States, paraquat has been available as a concentrated (29-44%) liquid. Diquat is found in aqueous concentrates containing 8-37.3% of the herbicide. Granular fonnulations containing a 2.5% mixture of paraquat and diquat salts are also available. 

On October 21,1959, a more concentrated wettable powder formulation, Atrazine 80 W, was registered and quickly became the leading com herbicide in the United States. Other formulations of atrazine, including various granulars... 

Figure 4.6 Granular application of herbicides was quickly adopted by farmers who were already familiar with granular fertilizer applicators in the Com Belt. (Courtesy of Dr. Ellery Knake, Professor Emeritus, University of Illinois.)...

On the other hand, the broad weed control spectrum of chloramben, which was introduced in 1959, brought with it widespread acceptance. As an over-the-row band for control of both broadleaf and grass weeds, cost was minimized. With good crop tolerance, chloramben dominated the early soybean herbicide market. During 1972, 85% of the product was applied as the granular formulation (Table 4.2). However, as application practices changed for the soybean crop, banded applications became an inconvenience. Herbicides such as metribuzin (a triazine herbicide), linuron, and bentazon, which could be applied as an affordable broadcast treatment, soon became products of choice, and the marketing of chloramben was eventually discontinued in 1990. 

The ability of one product to complement the characteristics of another has also had an effect on product acceptance. Although alachlor initially was used by itself as a banded granular grass herbicide on com and soybean, it was the tank mixes with broadleaf herbicides that propelled its success. Combinations of atrazine-alachlor, metribuzin-alachlor, and linuron-alachlor became very common. Alachlor replaced essentially all propachlor use on field corn over the 4-year period from 1972 to 1976, not only as a result of less hazardous handling characteristics (Table 4.1), but also as a consequence of its success in tank mixes. 

Triazine herbicides are primarily effective in controlling herbaceous weeds. A notable exception is the use of granular hexazinone for controlling woody invaders such as oaks (Quercus spp.) or aspen (Populus tremuloides) in conifer stands on medium- and fine-textured soils in the South or in boreal forests. Hexazinone also is used in the Maritime Provinces of Canada for controlling woody and herbaceous growth in natural Christmas tree stands (Townsend, 1995a). The impact of herbaceous plant cover is somewhat different from that of woody plant competitors, so control strategies on various forest conifer sites may differ. 

Uses Bromacil is a colorless crystalline solid. It is used for the control of annual and perennial grasses, broadleaf weeds, and woody plants.1213 Bromacil is a herbicide used for bush weed control on non-cropland areas. It is especially useful against perennial grasses. It is also used for selective weed control in pineapple and citrus crops. It interferes with photosynthesis of plants. It is available in granular, liquid, water-soluble liquid, and wettable powder formulations. 

SYNS BOREA BROMAZIL 5-BROMO-3-sec-BUTYU6-METHYLURACIL 5-BROMO-6-METHYL-3-(l-METHYLPROPYL)-2,4(lH,3H)-PYRIMIDINEDIONE 5-BROMO-6-METHYL-3-(l-METHYLPROPYL)URACIL 3-sek.BUTYL-5-BROM-6-METHYLURACIL (GERMAN) CYNOGAN DU PONT HERBICIDE 976 EEREX GRANULAR WEED KILLER EEREX WATER SOLUBLE CONCENTRATE WEED KILLER HERBICIDE 976 HYVAR HYVAREX HYVARX ... 

Granular formulations are used almost exclusively as soil treatments. They may be applied either directly to the soil or over the plants they do not cling to plant foliage. They may be used to control pests Uving at or below ground level or they may be absorbed by roots and translocated throughout the plant. The latter are, for the most part, either systemic insecticides or systemic herbicides. 

Use of granular activated carbon (GAC) is considered to be the best currently available technology for removing low-solubility contaminants such as disinfection by-products (usually from chlorination) that include trihalomethanes (THM), detergents, pesticides, herbicides, polyaromatic hydrocarbons, and some trace metals. The amendments to the Safe Drinking Water Act. state that other treatment technologies must be at least as effective as GAC [66]. 

Molinate is a selective thiocarbamate herbicide used to control broad-leaf and grassy plants primarily in rice production. Molinate is available in granular and emulsifiable liquid formulations. Recently, US manufacturers of molinate have requested voluntary cancellation of all uses of molinate by 2009. 

Avadex [Solutia]. TM for a series of liquid or granular herbicides containing 2,3-dichloroallyl dii-sopropylthiocarbamate. Widely used to control growth of wild oats in agricultural crops. 

Ramrod [Solutia], TM for selective preemergence herbicide available as a wettable powder (contains 65% 2-ch I or-A- i sopropy I acctan Hide) and granular form (contains 20% 2-chloro-iV-isopropy-lacetanilide). 

Briibach and Gohlich compared other methods for the determination of physical characteristics of granular fertilizers, insecticides, and herbicides with similar results, and corresponding conditions have been found for many other practical test methods which are being applied in industry. 

Residues from Control of Submersed Weeds. Recommendations for use of herbicides to control submersed aquatic weeds usually specify treatment concentrations in terms of ppm. Granular formulations of herbicides such as 2,4-D, 2,6-dichlorobenzonitrile (dichlobenil), and 2,3,6-trichlorophenylacetic acid (fenac) are applied at pound-per-acre rates. The herbicides most commonly used to control submersed aquatic weeds are listed in Table I with normal rates of application. The initial residue levels represent the concentrations effective on submersed vegetation. For comparison, treatment rates given in pounds per acre are also shown as ppm in an arbitrarily selected water depth of 4 feet. 

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