Plant protecting and regulating compositions – Plant growth regulating compositions – Plural active ingredients
Reexamination Certificate
1999-09-14
2001-08-21
Qazi, Sabiha (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Plural active ingredients
C504S127000, C504S128000, C504S130000
Reexamination Certificate
active
06277787
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.
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 provides a synergistic herbicidal composition which comprises an agriculturally acceptable carrier and 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.
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 at the rate at which they are present in the combination (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, or the agriculturally acceptable salt thereof. The imidazolinone compounds and their corresponding chemical names are listed herein below.
Imazethapyr designates 5-ethy1-2-(4-isopropy1-4-methy1-5-oxo-2-imidazolin-2-y1) nicotinic acid, the R isomer thereof, a salt thereof, or mixtures thereof.
Imazaquin designates 2-(4-isopropy1-4-methy1-5-oxo-2-imidazolin-2-y1) quinolinecarboxylic acid, the R isomer thereof, a salt thereof, or mixtures thereof.
Imazapic designates 2-(4-isopropy1-5-methy1-5-oxo-2-imidazolin-2-y1)-5-methylnicotinic acid, the R isomer thereof, a salt thereof, or mixtures thereof.
Imazamox designates 2-(4-isopropy1-4-methy1-5-oxo-2-imidazolin-2-y1)-5-(methoxymethyl)nicotinic acid, the R isomer thereof, a salt thereof, or mixtures thereof.
Imazapyr designates 2-(4-isopropy1-4-methy1-5-oxo-2-imidazolin-2-y1)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 specification and claims, the term R isomer designates the optical isomer of an imidazolinone compound having the R configuration assigned to the assymetric carbon in the imidazolinone ring which is substituted by a methyl and an isopropyl group, for example the R isomer of the imidazolinone compound imazapyr is shown low.
In general, commercial formulations of glyphosate are aqueous solutions of an agriculturally acceptable salt such as glyphosate-isopropylammonium, glyphosate-sesquisodium, glyphosate trimesium and the like. Similarly, imidazolinone herbicides and their agriculturally acceptable salts are commercially available as aqueous solutions. Additionally, imidazolinone herbicides are commercially available as dispersible granules, soluble granules and the like. In actual practice, the combination of the invention may be applied simultaneously (as a tank mix or a premix), separately or sequentially.
Thus, in accordance with the method of invention a synergistically effective amount of a combination of glyphosate and an imidazolinone compound selected from the group consisting of imazethapyr, imazaquin, imazapic, imazamox and imazapyr is applied to the locus, foliage or stems of undesirable plants, particularly plants selected from the genera Ipomoea, Cyperus, Sida and Euphorbia, preferably
Ipomoea lacunosa, Cyperus rotundus, Sida spinosa
and
Euphorbia maculata
, more preferably
Ipomoea lacumosa.
Preferred combinations of the invention are those combinations wherein the weight/weight (wt/wt) ratio of glyphosate:imidazolinone compound is about 3:1 to 65:1. More preferred combinations of the invention are combinations of glyphosate and imazethapyr wherein the wt/wt ratio of glyphosate:imazethapyr is about 8:1 to 12:1 or combinations of glyphosate and imazaquin wherein the wt/wt ratio of glyphosate:imazaquin is about 3:1 to 10:1 or combinations of glyphosate and imazapic wherein the wt/wt ratio of glyphosate:imazapic is about 15:1 to 65:1 or combinations of glyphosate and imazamox wherein the wt/wt ratio of glyphosate:imazamox is about 20:1 to 65:1.
The synergistically effecti
Malefyt Timothy
Salzman Frederick P.
Watkins Robert M.
American Cyanamid Co.
Hogan Jr. John W.
Maurer Barbara V.
Qazi Sabiha
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