Plant protecting and regulating compositions – Plant growth regulating compositions – Designated nonactive ingredient containing
Reexamination Certificate
2001-12-27
2004-02-10
Clardy, S. Mark (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Designated nonactive ingredient containing
C504S211000, C504S212000, C504S213000, C504S214000, C504S215000, C504S234000, C504S235000, C504S253000, C504S363000, C516S204000, C516S199000, C071S054000, C071S058000, C071S059000, C071S061000
Reexamination Certificate
active
06689720
ABSTRACT:
This invention relates to a homogenous adjuvant blend for use in spray carriers containing herbicides, which are used to control weeds or other undesired vegetation. More specifically, the homogenous adjuvant blend of the invention includes a blend of oil, a pH adjuster, and nonionic surfactants.
BACKGROUND
Herbicides used in controlling weeds or undesired vegetation in agriculture may be applied by postemergence spraying of a herbicide on the crop. The spray carrier for the herbicide is usually a water-based adjuvant mixture containing an effective amount of known herbicide. Adjuvants are commonly added to herbicidal spray mixtures to enhance postemergence weed control and/or to reduce spray drift during herbicide applications.
Postemergence weed control applications are enhanced when the spray containing the herbicide is retained on the weed surface. To obtain sufficient retention of the herbicide on the weed surface, many “sticker” compositions or agents, including methylated vegetable oils or mineral based oils and surface active agents (surfactants), are used as adjuvants. These adjuvants act to improve adherence of the herbicide on weeds, help retain droplets of the spray solution on the plant, and improve penetration of the herbicide into the plant.
In addition to spray retention by the weed, other additives in the form of liquid nitrogen based fertilizer solutions have been found, for example, to enhance the control of wild oats by herbicides such as barban. Miller et al.,
Weed Science,
1978, Vol. 4, pp. 344-348. Recently surfactants have been combined with liquid fertilizers (usually 28% nitrogen, comprising a mixture of about 50% ammonium nitrate and about 50% urea). The results however are variable depending on surfactants used and nitrogen fertilizer employed. It was found that certain salts and surfactants influence nicosulfuron herbicide activity. Nalewaja et al.,
Weed Technology,
1995, Vol. 9, pp. 587-593.
Some acidic additives have previously been used which are designed to lower pH and enhance the acidity of the spray carrier water formulation, which was believed to both benefit herbicide adsorption and also to prevent alkaline hydrolysis of certain insecticides. Acids and buffering agents are sometimes also used to reduce antagonism from alkaline salts found in the spray carrier water (U.S. Pat. Nos. 5,393,791; 5,178,795 and RE No. 37,313).
It has been noted that adjuvants differ greatly in herbicide enhancement depending on the specific surfactant and the herbicide used. In some cases, adjuvant can result in decreased performance. Halloway, 4
th International Symposium on Adjuvants for Agrochemicals,
1995, FR. & Bulletin, No. 193.
Adjuvants which are a three component system including an alkaline amine pH regulator, a non-ionic surfactant, and a neutral ammonium salt, such as ammonium nitrate, ammonium chloride, and ammonium sulfate, are described in U.S. Pat. No. 5,658,855. All three components were required to provide the desired phytotoxicity.
One concern over the use of adjuvants is not only in its ability to enhance herbicide efficacy but in its ability to maintain product stability. Many adjuvants may be blended with herbicides and water that are available at the site of blending. In some cases, the available blending water may contain minerals or other substances that result in formation of precipitates and general instability of the composition.
SUMMARY
The present invention relates to homogenous and stable adjuvant blends for use in a spray carrier of postemergence herbicides applied as an aqueous spray solution to areas infested with undesired weeds or plants to control the same. The adjuvant compositions of the present invention are stable and act synergistically at low rates to increase spray retention, and provide lipophilic and hydrophilic environments in the spray deposits that enhance leaf penetration and efficiacy of herbicides. The adjuvant of the present invention is provided as a single stable formulation that reduces the need to add separate components to a spray tank mix.
The adjuvant of the present invention is a multi-component composition that includes an oil, a pH adjuster for adjusting the pH to an alkaline range, and nonionic surfactants. In one aspect of the invention, the oil may be a petroleum oil. In this aspect, the adjuvant blend may only contain a petroleum oil, or alternatively, may further include an oil or mixture of oils selected from the group consisting of vegetable oils, methylated, ethylated and butylated seed oil, fatty acids, partially saponified fatty acids, and mixtures thereof. In the aspect of the invention where the adjuvant blend contains only petroleum oil, the blend contains from about 30 to about 70 weight percent petroleum oil, based on the weight of the adjuvant blend. In the aspect of the invention where the adjuvant blend contains petroleum oil and a second oil, the blend contains from about 1 to about 69 weight percent petroleum oil, based on the weight of the adjuvant blend, and from about 1 to about 69 weight percent, based on the weight of the adjuvant blend, of a second oil or mixture of second oils.
In another aspect of the invention, the blend includes an oil selected from the group consisting of petroleum oil, vegetable oils, methylated, ethylated and butylated seed oil, fatty acids, partially saponified fatty acids, and mixtures thereof. In this aspect of the invention, the blend contains from about 30 to about 70 weight percent oil or mixture of oils, based on the weight of the adjuvant blend.
The second component of the homogenous adjuvant blend of the present invention is a pH adjuster. The pH adjuster of the invention is effective for providing an alkaline pH of above about 7 up to about 10 for the final spray solution that is applied to the plants. The pH adjuster may be organic and/or inorganic. Examples of of pH adjusters include ammonium hydroxide, potassium hydroxide, sodium hydroxide, triethanolamine, primary amino alcohols, and mixtures thereof. In an important aspect of the invention, the pH adjuster component is about 0.01 weight percent to about 10 weight percent of the adjuvant composition, preferably about 5 percent by weight of the adjuvant composition.
The next components of the homogenous adjuvant blend is a nonionic surfactant. Nonionic surfactants useful in the present invention include linear alcohol ethoxylates, secondary alcohol ethoxylates, block copolymers of ethylene and propylene oxide, and mixtures thereof. The adjuvant blend contains from about 30 to about 70 weight percent nonionic surfactant, based on the weight of the adjuvant blend.
In another aspect, about 0.5 to about 1 percent of the homogenous adjuvant blend of the present invention is blended with water and with an effective amount of herbicide to provide a postemergence herbicidal spray composition, which is applied for weed control purposes. In this aspect of the invention, the herbicidal spray composition includes about 95 to about 99 percent water, about 0.001 to about 4 percent herbicide, and about 0.5 to about 1 percent of the adjuvant of the present invention, based on the weight of the herbicidal spray composition. The herbicide is customarily added to the water at the recommended label amount; for example, herbicide in an amount from about 0.1 to about 4 ounces per acre of the herbicide active ingredients is a typical application rate.
DETAILED DESCRIPTION
The homogenous adjuvant blend of the present invention is a multi-component mixture including an oil, pH adjuster, and nonionic surfactant. The percentage of each ingredient is blended to provide a homogenous and stable formulation. As used herein a “homogenous and stable” formulation means that all components of the adjuvant composition when mixed together form a clear, continuous blend that does not separate during storage at temperatures between 32° F. and 122° F. for at least about 180 days.
In an important aspect of the invention, the homogenous adjuvant blend increases the efficacy of certain herbicides. The ingredients, acting syn
Messersmith Calvin
Nalewaja John
Woznica Zenon J.
Clardy S. Mark
Fitch Even Tabin & Flannery
NDSU--Research Foundation
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