Plant protecting and regulating compositions – Plant growth regulating compositions – Plural active ingredients
Reexamination Certificate
2002-01-16
2002-11-26
Pryor, Alton (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Plural active ingredients
Reexamination Certificate
active
06486097
ABSTRACT:
BACKGROUND OF THE INVENTION
Control of undesired vegetation, e.g., weeds, is extremely important in achieving high crop efficiency and for aesthetic appearances at commercial and residential areas. Selective control of the growth of weeds, especially in crops as rice, soybean, sugar beet, corn (maize), potato, wheat, barley, tomato and plantation crops is very desirable. Unchecked weed growth in such crops can cause significant reduction in productivity and thereby result in increased costs to the consumer. The control of undesired vegetation in noncrop areas, e.g., residential areas, is also important.
One approach to control undesired vegetation is by defoliation. Defoliation can be accomplished by leaf injury with certain herbicides. The herbicide can be either of the contact or systemic variety. A contact herbicide requires that a substantial portion of the plant be contacted with the active ingredient of the herbicide being applied. A systemic herbicide translocates through the plant.
Certain herbicides include fatty acids as a component of the active ingredient. Fatty acid herbicides are known in the art and are generally considered to be environmentally friendly. Fatty acid herbicides are typically supplied as concentrates that are diluted with water and applied as an oil-in-water emulsion. These concentrates usually contain the fatty acid active ingredient an emulsifying agent including surfactants, or oils. Application rates vary but usually the fatty acid emulsions are applied at application rates of at least 50-100 gallons or more per acre and deliver the active fatty acid herbicide at concentrations of 1-8% by weight.
For example, U.S. Pat. Nos. 4,975,110; 5,106,410 and 5,098,467 disclose fatty acid herbicidal compositions that contain C8-12 fatty acids, a surfactant and water with pelargonic acid being a preferred fatty acid herbicide. U.S. Pat. Nos. 5,098,468 and 5,035,741 also disclose fatty acid herbicidal compositions that contain C8-12 carbon fatty acids, an oil component, an emulsifier and water. Single phase concentrates are disclosed in U.S. Pat. Nos. 5,098,468 and 5,035,741 that contain the fatty acid(s), oil and emulsifier. The concentrate is diluted with water to form a ready to use composition containing 1-8% by weight fatty acid which is applied at a rate of 8-200 gallons/acre.
Fatty acid herbicides include fatty acid esters of C6-C20 monocarboxylic acids such as those disclosed in U.S. Pat. No. 5,284,819. Additionally, fatty acid salts such as those disclosed in U.S. Pat. Nos. 2,626,862; 4,975,110; and 5,035,741, can be employed as fatty acid herbicides.
Maleic hydrazide (MH) is a plant growth regulator and is registered with the Environmental Protection Agency for certain select uses. On tobacco MH is used to prevent shoots arising from auxiliary buds (“suckers”), thereby maximizing the size and quality of the leaves on the main stem. NH is also commonly applied to potatoes and onions to inhibit sprouting, and to lawns to reduce growth, thereby reducing required maintenance and watering. MH is not regarded as a chemical that kills plants.
Although fatty acid herbicides are considered to be environmentally friendly, they are contact herbicides. Only the treated plant areas become necrotic. Plants with well established root systems are often able to re-grow following treatment with fatty acid herbicides. These weeds include dandelions and thistles. There is a need for products that have the safety of fatty acid herbicides and are able to kill weeds with established root systems.
SUMMARY OF THE INVENTION
The present invention provides an environmentally compatible herbicidal composition which can be advantageously synthesized on an industrial scale. The herbicidal compositions provide effective control of difficult weeds using environmentally friendly compounds.
The present invention is directed to a herbicide which contains, as an effective component, an herbicidally effective mixture of a carboxylic acid component having between one (1) and eighteen (18) carbon atoms and a derivative of maleic hydrazide. Preferably, the pH of the composition is greater than or equal to 6.
The carboxylic acid component of the herbicidal composition includes one or a mixture of alpha monocarboxylic acids having a hydrocarbon chain between one and eighteen carbon atoms. In a preferred embodiment, the hydrocarbon chain is between about two and eleven carbon atoms, most preferably nine or eleven carbon atoms, e.g., nonanoic acid or undecylenic. The hydrocarbon chain can be branched or unbranched, substituted or unsubstituted and/or include one or more sites of unsaturation, e.g., alkyene or alkyne moieties. Preferably, the hydrocarbon chain has nine carbon atoms, and is unbranched, unsubstituted and fully saturated.
The carboxylic acid component in the herbicidal composition is effective as an amide, in the free acid form, or, preferably as a salt. Amides include primary, secondary and tertiary amides. Suitable secondary and tertiary amides can have lower alkyl groups of between one and three carbon atoms. Salts of carboxylic acid include, but are not limited to sodium, potassium, lithium, magnesium, calcium, copper, iron, zinc, manganese, amines, and ammonium. Suitable amines include tertiary amine having lower alkyl groups of between one and three carbon atoms, e.g., triethylamine. Preferred salts include sodium, potassium and ammonium. A preferred salt for the carboxylic acid compositions of the invention is the ammonium salt, i.e., NH
4
+1
.
Derivatives of maleic hydrazide useful in the herbicidal composition include alkylated products of one or both nitrogens within the six membered ring of maleic hydrazide and, preferably, maleic hydrazide salts. Typically the alkylated derivatives of maleic hydrazide are of lower alkyl groups having carbon chain lengths of from one to about four carbon atoms. Salts of maleic hydrazide include, but are not limited to, sodium, potassium, lithium, magnesium, amines and, preferably ammonium salts. Suitable amines include tertiary amine having lower alkyl groups of between one and three carbon atoms, e.g., triethylamine. The concentration of the maleic hydrazide derivative in the herbicidal compositions is between about 0.5 to about 5%, preferably between about 0.5 to 2%, and most preferably about 1%.
The herbicidal compositions of the present invention are herbicides which have little or no residual soil activity as the composition is degraded and used as a nutrient source by soil microorganisms. The compositions are substantially nontoxic to humans and animals.
The herbicidal compositions of the invention are prepared in the form of a concentrate which includes the active ingredients (carboxylic acid component and a derivative of maleic hydrazide, e.g. a salt). As such, the composition can be prepared as a concentrate, which is easily shipped and stored, and can be subsequently diluted with water before use. The concentrate can comprise from approximately 20% to about 80% active ingredients. More preferably, the active ingredient present in the concentrate ranges from between about 20% and about 60%. To prepare a ready to use formulation, the concentrate is diluted with water so as to contain approximately 1% to about 8% active ingredients.
The invention is also drawn to methods for treating undesired grasses or weeds by applying a composition of a herbicidally effective amount of a carboxylic acid component and maleic hydrazide or a derivative of maleic hydrazide to said grasses or weeds, such that said grasses or weeds are controlled. It has been unexpectedly found that maleic hydrazide with a carboxylic acid component, as defined herein, is extremely effective in combating undesired weeds.
Other advantages of the invention will be readily apparent to one having ordinary skill in the art upon reading the following description.
All percentages by weight identified herein are based on the total weight of the herbicidal compositions unless otherwise indicated.
DETAILED DESCRIPTION OF THE INVENTION
The features and other details o
Sedun Frederick S.
Wilson Cameron D.
Nutter & McClennen & Fish LLP
Pryor Alton
W. Neudorff GmbH KG
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