Plant protecting and regulating compositions – Plant growth regulating compositions – Plural active ingredients
Reexamination Certificate
1999-09-14
2001-04-10
Dees, Jose′ G. (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Plural active ingredients
Reexamination Certificate
active
06214768
ABSTRACT:
BACKGROUND OF THE INVENTION
Certain weeds such as Ipomoea, Cyperus, Sida and Euphorbia are particularly difficult to control. Their full-season competition can reduce crop yields and cause significant economic loss in row-crop production. One of the most common practices for controlling these troublesome weeds is the postemergent application of a herbicide. However, there is no single selective herbicide currently available which will give economic control of these weeds.
Glyphosate [(N-phosphonomethyl)glycine] is a highly effective herbicide with a broad spectrum of activity. However, certain agronomically important weed species require relatively high application rates of glyphosate for effective control. High rates of glyphosate can lead to undesirable increased selection pressure. Glyphosate tolerance, particularly in Ipomoea, is a recognized problem in the field. Therefore, new weed control methods and compositions which effectively lower glyphosate application rates while providing broad spectrum weed control are highly desirable.
Aqueous compositions containing imidazolinyl acid salts are described in U.S. Pat. No. 4,816,060, and aqueous compositions containing glyphosate salts are described in EP 220,902-A2. However, concentrated, aqueous compositions comprising an imidazolinyl acid salt and a glyphosate salt have not been described. The principal reason that aqueous compositions containing both of those compounds have not been disclosed is that imidazolinyl acid salts and glyphosate salts are, in general, not mutually compatible. Aqueous glyphosate salt compositions generally have a pH value of about 4. However, imidazolinyl acid salts are not entirely stable in an environment having a pH value of about 4. Conversely, glyphosate salts are not entirely stable at the pH values required to provide stable aqueous compositions of imidazolinyl acid salts.
To overcome the incompatibility problems associated with aqueous compositions containing imidazolinyl acid salts and glyphosate salts, emulsifiable suspension concentrate compositions containing imidazolinyl acids and glyphosate have been described (see, e.g., U.S. Pat. No. 5,268,352). However, emulsifiable suspension concentrate compositions are not entirety satisfactory because they require the use of heavy aromatic solvents.
What is needed in the art is an aqueous composition which overcomes the incompatibility problems associated with imidazolinyl acid salts and glyphosate salts without requiring the use of heavy aromatic solvents.
SUMMARY OF THE INVENTION
Surprisingly, it has now been found that the combination of glyphosate with an imidazolinone compound provides synergistic weed control. Advantageously, the synergistic combination of the invention allows for lower application rates of glyphosate with concomittant increased spectrum of weed control. Moreover, the synergistic herbicidal methods and compositions of the invention allow for effective resistance management programs and provide improved control of pestiferous weeds such as Ipomoea in glyphosate-resistant crop production.
The present invention provides a method for the synergistic control of undesirable plants such as Ipomoea, Cyperus, Sida or Euphorbia which comprises applying to the locus of said plants or to the foliage or stems of said plants a synergistically effective amount of a combination of glyphosate and at least one imidazolinone compound selected from the group consisting of imazethapyr, the R isomer thereof or a salt thereof; imazaquin, the R isomer thereof or a salt thereof; imazapic, the R isomer thereof or a salt thereof; imazamox, the R isomer thereof or a salt thereof; imazapyr, the R isomer thereof or a salt thereof; and mixtures thereof.
The present invention also relates to a concentrated, aqueous herbicidal composition which comprises about 0.1% w/v to about 7% w/v of an imidazolinyl acid salt, about 10% w/v to about 45% w/v of a glyphosate salt, about 0.5% w/v to about 6% w/v of dimethyl sulfoxide, about 0.5% w/v to about 15% w/v of a wetting agent, up to about 10% w/v of an antifreezing agent, up to about 1% w/v of an antifoaming agent, up to about 5% w/v of a base, and water, provided that the composition has an initial pH of from about 6.0 to about 7.2.
Preferred concentrated, aqueous herbicidal compositions of this invention comprise about 0.1% w/v to about 7% w/v of an imidazolinyl acid salt, about 15% w/v to about 45% w/v of a glyphosate salt, about 0.5% w/v to about 6% w/v of dimethyl sulfoxide, about 0.5% w/v to about 15% w/v of a wetting agent, up to about 10% w/v of an antifreezing agent, up to about 1% w/v of an anti-foaming agent, up to about 3% w/v of a base, and water, provided that the composition has an initial pH of from about 6.0 to about 7.0.
The present invention further relates to a process or the preparation of the concentrated, aqueous herbicidal compositions of this invention.
DETAILED DESCRIPTION OF THE INVENTION
Glyphosate [(N-phosphonomethyl)glycine] is a highly effective broad spectrum herbicide. However, certain troublesome weeds such as Ipomoea, Sida, Cyperus and Euphorbia may require very high application rates of glyphosate for effective control. High application rates of glyphosate may decrease the margin of crop safety, increase the potential development of weed tolerance and result in the loss of economic weed control.
Surprisingly, it has now been found that the application of a combination of glyphosate plus at least one imidazolinone compound selected from imazethapyr, the R isomer thereof or a salt thereof; imazaquin, the R isomer thereof or a salt thereof; imazamox, the R isomer thereof or a salt thereof; imazapic, the R isomer thereof or a salt thereof; and imazapyr, the R isomer thereof or a salt thereof provides synergistic control of troublesome weeds, particularly Ipomoea, Sida, Cyperus and Euphorbia, especially Ipomoea. That is, the application of the combination of the invention gives a mutual reinforcing action such that the application rates of the individual herbicidal components can be reduced and still the same herbicidal effect is achieved or, alternatively, the application of the combination of herbicidal components demonstrates a greater herbicidal effect than expected from the effect of the application of the individual herbicidal components when applied singly (synergistic effect).
As used in the specification and claims, the term glyphosate designates the compound N-(phosphonomethyl)-glycine or the agriculturally acceptable salts thereof. Similarly, the terms used for the imidazolinone compounds imazethapyr, imazaquin, imazapic, imazamox and imazapyr as they appear in the specification and claims designate the compound, the R isomer thereof, an agriculturally acceptable salt thereof or mixtures thereof unless the context clearly dictates otherwise. The imidazolinone compounds and their corresponding chemical names are listed herein below.
Imazethapyr designates 5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid, the R isomer thereof, a salt thereof, or mixtures thereof.
Imazaquin designates 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)quinolinecarboxylic acid, the R isomer thereof, a salt thereof, or mixtures thereof.
Imazapic designates 2-(4-isopropyl-5-methyl-5-oxo-2-imidazolin-2-yl)-5-methylnicotinic acid, the R isomer thereof, a salt thereof, or mixtures thereof.
Imazamox designates 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-5-(methoxymethyl)nicotinic acid, the R isomer thereof, a salt thereof, or mixtures thereof.
Imazapyr designates 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid, the R isomer thereof, a salt thereof, or mixtures thereof.
In the context of the present invention, the term agriculturally acceptable salt includes alkali metal, ammonium, alkyl sulphonium or alkylphosphonium salt or the quatenary salt of an amine having a molecular weight of less than 300. In particular, the term includes isopropylammonium, ammonium, sodium and trimesium, especially isopropylammonium and ammonium.
As used in the
Castro Kelly Neoob DeCarvalao
Malefyt Timothy
Mendonca Wilson
Salzman Frederick P.
Watkins Robert M.
American Cyanamid Co.
Dees Jose′ G.
Hogan Jr. John W.
Maurer Barbara V.
Pryor Alton
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