Plant protecting and regulating compositions – Plant growth regulating compositions – Organic active compound containing
Reexamination Certificate
2001-11-14
2003-11-04
Clardy, S. Mark (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Organic active compound containing
C504S234000, C504S235000, C504S253000, C504S343000, C504S363000, C071S054000, C071S059000, C071S061000
Reexamination Certificate
active
06642178
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 neutral blend of nitrogen fertilizer, a pH adjuster, modified vegetable oil, and a blend of nonionic surfactants having high, intermediate, and low hydrophilic-lipophilic balance (HLB).
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.
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 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, prevent pesticide antagonism from salts in spray water, 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 a neutral blend of nitrogen fertilizers, modified vegetable oil, a pH adjuster which is the base for adjusting the pH to the alkaline range, and a blend of high, intermediate, and low hydrophilic-lipophilic balance (HLB) nonionic surfactants.
Nitrogen fertilizers include nitrogen fertilizers such as ammonium nitrate, urea, ammonium chloride, ammonium nitrate-urea fertilizer solutions, ammonium sulfate, and mixtures thereof. In an important aspect of the invention, the nitrogen fertilizer ranges from about 30 to about 45 percent by weight of the concentrate adjuvant composition. The preferred nitrogen fertilizer is ammonium nitrate-urea fertilizer where the percent of nitrogen is about 2 percent to about 34 percent, preferably about 28 percent.
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 triethanolamine, primary amino alcohols, ammonium hydroxide and mixtures thereof. In an important aspect of the invention, the pH adjuster component is about 0.1 weight percent to about 20 weight percent of the adjuvant composition, preferably about 10 percent by weight of the adjuvant composition.
The third component of the homogenous adjuvant blend is modified vegetable oil. The modified vegetable oil may be selected from a group including methylated, ethylated, and butylated seed oils from all major crops. In an important aspect of the invention, the preferred modified vegetable oil is methylated canola oil. The modified vegetable oil of the composition is about 5 weight percent to about 80 weight percent by weight of the adjuvant composition, and preferably is about 20 percent by weight of the adjuvant composition.
The next components of the homogenous adjuvant blend are two nonionic surfactants. In an important aspect of the invention, the nonionic surfactants are block copolymers. One of the block copolymer surfactants has a high HLB above about 14 and the other nonionic block copolymer surfactant has a HLB of 10 or less. In an important aspect, the high HLB nonionic surfactant has a HLB of above about 14 to about 18. The low HLB nonionic surfactant has a HLB of above about 1 to about 10. Each block copolymer surfactant component is about 1 to about 20 weight percent of the adjuvant composition, preferably about 1 to about 10 weight percent of the adjuvant composition, and more preferably is about 6 percent by weight of the adjuvant composition. Block copolymers useful in the present invention include copolymers of propylene oxide and ethylene oxide.
The adjuvant composition further includes at least two intermediate HLB nonionic surfactants. The intermediate nonionic surfactant may be a nonionic secondary alcohol ethoxylate surfactant having intermediate HLB values above about 10 to about 14. Each secondary alcohol ethoxylate surfactant is about 3 to about 33 weight percent of the adjuvant composition.
In another aspect, 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 99 percent water, about 0.001 to about 4 percent herbicide, and 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 o
Messersmith Calvin
Nalewaja John
Woznica Zenon J.
Clardy S. Mark
Fitch Even Tabin & Flannery
North Dakota State University
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