Plant protecting and regulating compositions – Plant growth regulating compositions – Plural active ingredients
Reexamination Certificate
2001-05-11
2002-08-20
Clardy, S. Mark (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Plural active ingredients
Reexamination Certificate
active
06436874
ABSTRACT:
The invention is in the field of the crop protection compositions which can be used against undesirable vegetation and which contain a combination of more than two herbicides as herbicidally active compounds.
More specifically, the invention relates to herbicidal compositions which comprise, as active compound, a broad-spectrum herbicide of the type of the leaf-acting herbicides, such as glufosinate, bialaphos, glyphosate and sulfosate in combination with two other herbicides from certain other substance classes.
The abovementioned leaf-acting herbicides are taken up via the green parts of the plants and are known as broad-spectrum herbicides or total herbicides; see “The Pesticide Manual” 11th Edition, British Crop Protection Council 1997, pp. 120, 382 and 646. They are predominantly employed by the post-emergence method, for controlling broad-leaved weeds and weed grasses in plantation crops and on uncultivated land and, by means of specific application techniques, also for inter-row treatment in agricultural row crops such as maize, cotton and the like. A further area of use of increasing importance is in transgenic crops of plants which are resistant to the herbicides.
The efficacy of herbicides depends, inter alia, on the type of herbicide employed, on its application rate, on the formulation, on the harmful plants to be controlled in each case, on the climatic and soil conditions, etc. A further criterium is the duration of the action, or the rate of degradation of the herbicide. Also to be taken into account are, if appropriate, changes in the susceptibility of harmful plants toward an active compound which may occur on prolonged use or when geographically restricted; loss of activity up to resistance of harmful plants can only be compensated to a certain degree by higher application rates of the herbicides.
Owing to the large number of possible influencing factors, there is virtually no individual active compound in which the desired properties for various requirements, in particular with regard to the species of the harmful plants and the climatic zones, are combined. There is additionally the permanent object of achieving the effect with ever lower herbicide application rates. A lower application rate does not only reduce the amount of an active compound which is required for the application, but usually also reduces the amount of formulation auxiliaries required. Both reduce the economic expense and improve the ecological compatibility of the herbicide treatment.
A method which is frequently employed for improving the property profile of a herbicide consists of the combination of the active compound with one or more other active compounds which contribute the desired additional properties. However, when two or more active compounds are applied in combination, it is not uncommon for phenomena of physical and biological incompatibility to occur, for example lack of stability of a coformulation, decomposition of an active compound or antagonism of the active compounds. In contrast, what is desired are combinations of active compounds having a favorable activity profile, high stability and as synergistically enhanced an activity as possible which permits a reduction of the application rate, compared with the individual application of the active compounds to be combined.
Surprisingly, it has now been found that active compounds from the group of the abovementioned leaf-acting herbicides interact in a particularly favorable manner with a combination of herbicides from the group of the imidazolinones and the growth-promoting herbicides.
The invention accordingly provides herbicidal compositions comprising an effective amount of a combination of
A) one or more leaf-acting herbicides from the group of the compounds of the formulae (A1) and (A2) and their esters and salts,
in which Z is a radical of the formula —OH or a peptide radical of the formula —NHCH(CH
3
)CONHCH(CH
3
)COOH or —NHCH(CH
3
)CONHCH[CH
2
CH(CH
3
)
2
]COOH,
B) one or more active compounds from the group of the imidazolinone herbicides, preferably imazapyr, imazethapyr, imazamethabenz, in particular imazapyr, and their salts,
C) one or more active compounds from the group of the growth-promoting herbicides, preferably 2,4-D and MCPA.
It is already known from EP-A-0252237 (CA-A-1291344) to combine glufosinate and its salts with imidazolinone herbicides, in which synergistic activity increases have been observed. From EP-A-0502014 (U.S. Pat. No. 5,525,578), it is known that the activity of combinations of glufosinate and imidazolinones can be increased by addition of certain surfactants, for example from the series of the fatty alcohol polyglycol ether sulfates.
Synergistic combinations of glufosinate with growth-promoting herbicides such as 2,4-D, MCPA, 2,3,6-TBA, CMPP, dichlorprop, 2,4-DB, MCPB and dicamba are known from DE-A-2856260 (GB-A-2011416).
Int. Patent Appl. No. PCT/EP99/03987 (Aventis CS Ref.: AGR1998/M216) SUPPLEMENTARY SHEET
3
a
From DE-A-4019362, it is known to combine glyphosate or its derivatives with certain surfactants as activators, it being possible for the combination to comprise further known active compounds. Possible active combination partners which are mentioned are, inter alia, 2,4-D, 2,4-DB, MCPP or else imidazolinones, such as imazaquin and imazapur.
From EP-A-0569944, it is known to combine herbicidal imidazolinones from the group consisting of imazaquin, imazethapyr and imazethamethapyr with herbicides from the group consisting of dicamba, 2,4-D, bromoxynil, pyridate, cyclohexanediones and sulfonylureas, where synergistic activity increases were observed, too.
Furthermore, reports on field trials of the following combinations are known: glyphosate and 2,4-D or dicamba (see Weed Science, Vol. 37, No.1, 1989, pp.12-18), glyphosate and imazaquin (see Weed Technology, Vol. 6, No. 1, 1992, pp. 45-51), glufosinate or glyphosate and imazaquin (see Weed Technology, Vol. 8, No. 1, 1994, pp. 17-22) and glyphosate and imazapyr (see Weed Technology, Vol.11, No. 1, 1997, pp. 76-80).
A mixture of imazamethabenz and mecoprop was commercially available or recommended (see “The Pesticide Manual” 10th edition 1994, p. 583, section “Applications”).
Surprisingly, the combinations of herbicides A+B+C according to the invention permit synergistic activity increases which exceed, by a wide margin and in an unexpected manner, the activity increases achieved with the two-compound combinations A+B and A+C.
The formula (A1) embraces all stereoisomers and mixtures thereof, in particular the racemate and the respective enantiomer which is biologically active, for example L-glufosinate and its salts. Examples of active compounds of the formula (A1) are the following:
(A1.1) Glufosinate in the narrow sense, i.e. D,L-2-amino-4-[hydroxy(methyl)phosphinyl]butanoic acid,
(A1.2) Glufosinate-monoammonium salt,
(A1.3) L-Glufosinate, L- or (2S)-2-amino-4-[hydroxy(methyl)phosphinyl]-butanoic acid,
(A1.4) L-Glufosinate-monoammonium salt, (A1.5) Bialaphos (or bilanafos), i.e. L-2-amino-4-[hydroxy(methyl)phosphinyl ]-butanoyl-L-alanyl-L-alanine, in particular its sodium salt.
Glufosinate is usually employed in the form of a salt, preferably the ammonium salt. The racemate of glufosinate or glufosinate-ammonium on its own is usually applied in dosages between 200 and 1000 g of AS/ha (=g of a.i./ha=gram of active substance per hectare). At these dosages, glufosinate is effective especially when it is taken up via green parts of the plant. Since it is degraded microbially in the soil within a few days, it is does not persist in the soil. This applies similarly also to the related active compound bialaphos-sodium; see “The Pesticide Manual” 11th edition, British Crop Protection Council 1997, p. 382 and p. 120.
In the combinations according to the invention, there is generally considerably less active compound (A1) required, for example an application rate in the range from 20 to 500, preferably from 20 to 100, gram of active substance glufosinate pe
Anthonysamy Daniel
Jagdish Singh Gill
Kuah Tai Choon
Ooi Soon Huat
Aventis CropScience GmbH
Clardy S. Mark
Frommer & Lawrence & Haug LLP
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