Herbicidal mixtures

Details Herbicidal mixtures Herbicidal mixtures

2001-08-24

2004-01-27

Clardy, S. Mark (Department: 1616)

Plant protecting and regulating compositions

Plant growth regulating compositions

Plural active ingredients

C504S132000, C504S134000, C504S136000, C504S242000

Reexamination Certificate

active

06683027

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to an improvement in the efficacy of herbicidal 2-phenyl-4-(hetero-)aryloxypyrimidines by combination with a selected second herbicidal compound and/or a safener.
The herbicidal 2-phenyl-4-(hetero-)aryloxypyrimidines to be used according to the present invention are a group of compounds, disclosed for example by the European Patent Application EP 0 723 960, which display excellent herbicidal performance, in particular against broad-leaved weeds in cereal crops. However, the 2-phenyl-4-(hetero-)aryloxypyrimidines, when used as the sole active ingredient, do not always achieve effective control of the full spectrum of weed species encountered in commercial agronomic applications, in conjunction with reliable selectivity for the crop species. Such gaps in the spectrum of control can be overcome by co-treatment with another herbicide known to be effective against the relevant weed species and/or with a safener to reduce crop injury.
SUMMARY OF THE INVENTION
The present invention relates to a herbicidal composition comprising, as active ingredient, a synergistically effective amount of
(1) at least one 2-phenyl-4-(hetero-)aryloxypyrimidines of formula I
 wherein
A represents an optionally substituted phenyl group or an optionally substituted 5- or 6-membered nitrogen-containing heteroaromatic group or a difluorobenzodioxolyl group;
m represents an integer from 0 to 2;
n represents an integer from 0 to 5;
R
1
(or each R
1
) independently represents a halogen atom, an optionally substituted alkyl, alkenyl, alkinyl, alkoxy, alkoxyalkyl, dialkoxyalkyl, alkoxyalkoxy, alkylthio, amino, alkylamino, dialkylamino, alkoxyamino or formamidino group;
R
2
(or each R
2
) independently represents a halogen atom, an optionally substituted alkyl, alkenyl, alkinyl, haloalkyl, haloalkoxy, alkoxy, alkoxyalkyl, alkoxyalkoxy, alkylthio, haloalkylthio group or a nitro, cyano, SF
5
or a alkylsulphonyl or alkylsulfinyl group; or its environmentally compatible salts;
(2) at least one additional herbicidal compound, which is active against broad-leaved weeds and/or annual grasses;
 and/or
(3) at least one additional safening compound.
The present invention also includes a method for controlling undesirable plant species comprising application of at least one compound of group (1) and at least one compound of group (2), and/or at least one compound of group (3), as defined above. In the method of this invention, these compounds may be applied separately or together, in herbicidally effective and/or safening amounts.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Surprisingly, it has now been found, that the combined herbicidal activity of compounds from the above mentioned 2-phenyl-4-(hetero-)aryloxypyrimidines with various compounds of group (2) against many broad-leaved weeds and annual grasses is much greater than expected when applied pre- or post-emergence and that this activity cannot be ascribed to an additive effect, but to a remarkable degree of synergism on many broad-leaved weed species and annual grasses, for example on grass weeds such as
Alopecurus myosuroides, Apera spica
-
venti, Lolium perenne, Setaria viridis,
and broadleaf weeds such as
Galium aparine, Lamium purpureum, Matricaria inodora, Papaver rhoeas, Stellaria media
and
Veronica persica.
(i.e. the combinations according to the invention show a much higher level of activity than predicted from that of the individual compounds) which enables also a greater selectivity for the crop species.
Also it has been found now that injuries on crop plants caused by a compound of group (1) or by a mixture of a compound of group (1) and a compound of group (2) may be reduced by additionally applying a compound of group (3).
A mixture of herbicides shows synergistic effect if the herbicidal activity of the mixture is larger than the sum of activities of the separately applied compounds. The expected herbicidal activity for a given mixture of two herbicides can be calculated as follows (See Colby, S. R., “Calculating synergistic and antagonistic response of herbicide combinations”, Weeds 15, pp 20-22 (1967):
WE
=
X
+
Y
×
(
100
-
X
)
100
wherein
X is the percentage of growth inhibition upon treatment with a herbicide 1 at a dose of p kg/ha compared with an untreated control (X=0%)
Y is the percentage of growth inhibition treatment with a herbicide 2 at a dose of q kg/ha compared with an untreated control
WE is the herbicidal effect to be expected upon treatment (% of growth inhibition compared with untreated control) with a combination of herbicide 1 and 2 at a dose of p+q g/ha, respectively.
If the actual weed control (W) exceeds the expected (calculated) weed control (WE), the mixture displays a synergistic effect.
The compounds of group (1), (2) and (3) can exist, or be used, in the form of the pure enantiomers and also as racemates or diastereomer mixtures.
They may also exist in the form of their environmentally compatible salts, esters, thioesters and amides.
Suitable salts, esters, thioesters and amides are, in general, those ones which do not adversely affect the herbicidal action of the active ingredients.
Suitable cations are, in particular, ions of the alkali metals, preferably lithium, sodium and potassium, of the alkaline earth metals, preferably calcium and magnesium, and of the transition metals, preferably manganese, copper, zinc and iron, and also ammonium, it being possible in this case, if desired, for one to four hydrogen atoms to be replaced by C
1
-C
4
-alkyl, hydroxy-C
1
-C
4
-alkyl, C
1
-C
4
-alkoxy-C
1
-C
4
-alkyl, hydroxy-C
1
-C
4
-alkoxy-C
1
-C
4
-alkyl, phenyl or benzyl, preferably ammonium, dimethylammonium, diisopropylammonium, tetramethylammonium, tetrabutylammonium, 2-(2-hydroxyeth-1-oxy)eth-1-yl ammonium, di(2-hydroxyeth-1-yl)ammonium, trimethylbenzylammonium, furthermore phosphonium ions, sulfonium ions, preferably tri(C
1
-C
4
-alkyl)sulfonium and sulfoxonium ions, preferably, tri(C
1
-C
4
-alkyl)sulfoxonium.
Anions of suitable acid addition salts are mainly chloride, bromide, fluoride, hydrogen sulfate, sulfate, dihydrogen phosphate, hydrogen phosphate, nitrate, hydrogen carbonate, carbonate, hexafluorosilicate, hexafluorophosphate, benzoate and the anions of C
1
-C
4
-alkanoic acids, preferably formate, acetate, propionate and butyrate.
Suitable esters are alkyl-, alkoxyalkyl-, allyl- and propargyl-esters, especially C
1-10
-alkyl esters for example methyl-, ethyl-, propyl-, isopropyl-, butyl-, isobutyl-, pentyl-, mexyl-(1-methylhexyl) or isooctyl(2-ethylhexyl)ester, C
1-4
alkoxyethylester for example methoxyethyl-, ethoxyethyl- or butoxyethylester, allyl esters and propargyl esters.
Suitable thioesters are alkylthioesters, especially C
1-10
-alkylthio esters for example ethylthio ester.
Suitable amides are alkyl amides, especially methyl amide and dimethylamide, and aryl amides like phenyl amide or 2-chloro-phenyl amide.
The organic moieties mentioned for the substituents R
1
, R
2
and R
a
to R
f
or as radicals on phenyl or heteroaromatic rings represent collective terms for individual enumerations of the individual group members. All hydrocarbon chains, ie. all alkyl, haloalkyl, alkoxy, haloalkoxy, alkylthio, alkylsulfinyl, alkylsulfonyl and alkoxycarbonyl moieties can be straight chain or branched. Unless otherwise specified, halogenated substituents preferably have attached to them one to five identical or different halogen atoms. Halogen means in each case fluorine, chlorine, bromine or iodine.
Examples for other meanings are:
C
1-2
alkyl: methyl or ethyl;
C
1-4
alkyl: C
1-2
alkyl as mentioned above, and also n-propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl or 1,1-methylethyl;
C
1-6
alkyl: C
1-4
alkyl as mentioned above, and also pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimeth

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