AU652481B2 - Synergistic herbicidal compositions - Google Patents

Description

SYNERGISTIC HERBICIDAL COMPOSITIONS

This invention relates to a new herbicidal composition having synergistic activity comprising a mixture of

6-(6,6-dimethyl-3,5,6,7-tetrahydropyrrolo- [2,1-c][1,2,4]thiadiazol-3-ylidenimino)-7-fluoro- 4-(2-propynyl)-2H-1,4-benzoxazin-3(4H)-one

and another selective herbicide and its use for combating weeds in crops.

The herbicidal activity of 6-(6,6-dimethyl- 3,5,6,7-tetrahydropyrrolo[2,1-c][1,2,4]thiadiazol- 3-ylidenimino)-7-fluoro-4-(2-propynyl)-2H-1,4-benzoxazin- 3(4H)-one is already known (EP 311 135). This compound has the following chemical structure (I)

(I)

Selective herbicides which inhibit directly or indirectly photosynthesis, demonstrate inhibition of cell division or possess hormone type activity are generally known. The known substances however are not always satisfactory in their activity in all areas of use.

It has now been found that a herbicidal composition which comprises, as active components, a mixture of

6-(6,6-dimethyl-3,5,6,7-tetrahydropyrrolo-

[2,1-c][1,2,4]thiadiazol-3-ylidenimino)-7-fluoro- 4-(2-propynyl)-2H-1,4-benzoxazin-3(4H)-one and anooher selective herbicide shows especially high activity without losing the selectivity properties in agricultural crops.

Surprisingly the herbicidal activity of the combination of the active ingredients of the invention is essentially higher than the individual components and also of the sum of the individual components. A synergistic effect is also seen. Especially suitable are mixtures which contain as a mixture component the selective herbicides cyanazine, ioxynil, isoproturon, methabenzthiazuron, bifenox,

chlorsulfuron, metsulfuron-methyl, pendimethalin,

benfuresate, thifensulfuron-methyl, isoxaben,

imazamethabenz, triasulfuron, amidosulfuron, ethofumesate, diflufenican, tribenuron-methyl, mecoprop, 2,4-D,

benazolin-ethyl, fluroxypyr or quinmerac.

Cyanazine is the common name for 2-chloro-4-(1-cyano- 1-methylethylamino)-6-ethylamino-1,3,5-triazine;

ioxynil is the common name for 4-hydroxy-3,5-diiodo- benzonitrile;

isoproturon is the common name for 3-(4-isopropylphenyl)- 1,1-dimethylurea;

methabenzthiazuron is the common name for 1-(benzothiazol- 2-yl)-1,3-dimethylurea;

bifenox is the common name for methyl 5-(2,4-dichloro- phenoxy)-2-benzoate;

chlorsulfuron is the common name for 1-(2-chlorophenyl- sulfonyl)-3-(4-methoxy-3-methyl-1,3,5-triazin-2-yl)urea; metsulfuron-methyl is the common name for methyl

2-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl) amino- carbonylaminosulfonyl]benzoate;

pendimethalin is the common name for N-(1-ethylpropyl)- 3,4-dimethyl-2,6-dinitroaniline; benfuresate is the common name for 2,3-dihydro- 3,3-dimethyl-5-benzofuranyl ethanesulfonate;

thifensulfuron-methyl is the common name for methyl

3-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl) amino- carbonylaminosulfonyl]-2-thiophenecarboxylate;

isoxaben is the common name for N-[3-(1-ethyl-1-methyl- propyl)isoxazol-5-yl]-2,6-dimethoxybenzamide;

imazamethabenz is the common name for 2-[4-isopropyl- 4-methyl-5-oxo-2-imidazolin-2-yl)-4 (5) -methylbenzoate; triasulfuron is the common name for 1-(2-chlorethoxy)-

N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]- benzenesulfonamide;

amidosulfuron is the common name for 1-(4,6-dimethoxy- pyrimidin-2-yl)-3-(N-methyl-N-methylsulfonylsulfamoyl)- urea;

ethofumesate is the common name for 2-ethoxy-2,3-dihydro- 3,3-dimethyl-5-benzofuranyl methanesulfonate;

diflufenican is the common name for 2'4'-difluoro- 2-(α,α,α-trifluoro-m-tolyloxy) nicotinanilide;

tribenuron-methyl is the common name for methyl

2-[4-methoxy-6-methyl-1, 3 , 5-triazin-2-yl(methyl)- carbamoylsulfamoyl]benzoate;

mecoprop is the common name for (RS)-2-(4-chloro- 2-methylphenoxy)propionic acid;

2,4-D is the common name for 2-(4-chloro-2-methyl- phenoxy) acetic acid;

benazolin-ethyl is the common name for ethyl (4-chloro- 2,3-dihydro-2-oxo-1,3-benzothiazol-3-yl) acetate;

dicamba is the common name for 3,6-dichloro-2-methoxy- benzoic acid

fluroxypyr is the common name for (4-amino-3,5-dichloro- 6-fluoro-2-pyridyloxy) acetic acid; and

guinmerac is the common name for 7-chloro-3-methyl- 8-quinollnecarboxyiate. The combination of active ingredients of the invention can used for example against the following plant species:

Dicotyledonous weeds of the species Sinapis, Lepidium, Galium, Stellaria, Matricaria, Anthemis, Galinsoga,

Chenopodium, Brassica, Urtica, Senecio, Amaranthus,

Portulaca, Xanthium, Convolvulus, Ipomoea, Polygonum, Sesbania, Ambrosia, Cirsium, Carduus, Sonchus, Solanum, Rorippa, Lamium, Veronica, Abutilon, Datura, Viola,

Galeopsis, Papaver, Centaurea and Chrysanthemum.

Monocotyledonous weeds of the species Avena, Alopecurus, Echinochloa, Setaria, Panicum, Digitaria, Poa, Eleusine, Brachiaria, Lolium, Bromus, Cyperus, Agropyron,

Sagittaria, Monocharia, Fimbristylis, Eleocharis,

Ischaemum and Apera.

The combinations can be applied pre or post-emergently, but generally pre-emergently. Selectivity is seen in range of crops such as maize, cereals and sunflowers. The rate of use lies between 0.001 and 5 kg/ha of the mixture, depending on the use. By using the mixtures for control of weeds the amount of herbicide needed can be generally reduced.

The weight ratio of component a) to b) is generally

between 1:50 and 50:1.

The mixtures of the invention can also be used in

admixture with other active agents for example other plant-protection agents or pesticides.

An improvement in the intensity and speed of action can be obtained, for example, by addition of suitable adjuvants, such as organic solvents, wetting agents and oils. Such additives may allow a decrease in the dose.

The designated active ingredients or their mixtures can suitably be used, for example, as powders, dusts,

granules, solutions, emulsions or suspensions, with the addition of liquid and/or solid carriers and/or diluents and, optionally, binding, wetting, emulsifying and/or dispersing adjuvants. Suitable liquid carriers are, for example aliphatic and aromatic hydrocarbons, such as benzene, toluene, xylene, cyclohexanone, isophorone, dimethyl sulfoxide,

dimethylformamide and other mineral-oil fractions and plant oils.

Suitable solid carriers include mineral earths, e.g.

bentonite, silica gel, talc, kaolin, attapulgite,

limestone, silicic acid and plant products, e.g. flours. As surface-active agents there can be used for example calcium lignosulfonate, polyoxyethylenealkylphenyl ethers, naphthalenesulfonic acids and their salts, phenolsulfonic acids and their salts, formaldehyde condensates, fatty alcohol sulfates, as well as substituted benzenesulfonic acids and their salts.

The percentage of the active ingredient(s) in the various preparations can vary within wide limits. For example, the compositions can contain about 10 to 90 percent by weight active ingredients, and about 90 to 10 percent by weight liquid or solid carriers, as well as, optionally up to 20 percent by weight of surfactant.

The agents can be applied in customary fashion, for example with water as the carrier in spray mixture volumes of approximately 100 to 1,000 l/ha. The agents can be applied using low-volume or ultra-low-volume techniques or in the form of so-called microgranules.

The preparation of these formulations can be carried out in known manner, for example by milling or mixing

processes. Optionally, individual components can be mixed just before use for example by the so-called commonly used tank-mixing method.

The following Examples illustrate the use of compositions of the invention.

The calculation of synergistic effect is carried out according to S R Colby "Calculating Synergistic and

Antagonistic Response to Herbicide Combinations" , Weeds, 15/1, 1967 pages 20 to 22. In this the following formula was used:

XY

E = X + Y - ------

100

in which X = the herbicidal activity (%) of substance A at a rate of p g/ha.

Y = the herbicidal. activity (%) of substance B at a rate of q g/ha., and

E = the expected additive activity of the

herbicide (%) of the substances A + B at a rate of p + q g/ha.

If the observed value is greater than the value of E calculated according to Colby, the combination shows synergistic activity. Experiments

In a greenhouse the plant species shown in the tables were treated pre-emergently with the components at the stated rates. The compositions were diluted with 500 litres of water and sprayed over the soil. Two weeks after treatment the herbicidal effect was evaluated. In the examples component I is 6-(6,6-dimethyl-3,5,6,7-tetrahydropyrrolo- [2,1-c][1,2,4]thiadiazol-3-ylidenimino)-7-fluoro- 4-(2-propynyl)-2H-1,4-benzoxazin-3 (4H) -onn

Claims

Claims

1. A herbicidal composition which comprises, as active components, a mixture of 6-(6,6-dimethyl-

3,5,6,7-tetrahydropyrrolo[2,1-c][1,2,4]thiadiazol- 3-ylidenimino)-7-fluoro-4-(2-propynyl)-2H-1,4-benzoxazin- 3(4H)-one and another selective herbicide.

2. A composition according to claim 1 which contains cyanazine, ioxynil, isoproturon, methabenzthiazuron, bifenox, chlorsulfuron, metsulfuron-methyl, pendimethalin, benfuresate, thifensulfuron-methyl, isoxaben,

imazamethabenz, triasulfuron, amidosulfuron, ethofumesate, diflufenican, tribenuron-methyl, mecoprop, 2,4-D,

benazolin-ethyl, fluroxypyr or quinmerac as the other selective herbicide.

3. A composition according to claims 1 or 2 in which the weight ratio of the mixture components is between 1:50 and 50:1.

4. A method of combating weeds which comprises applying post emergently a composition as claimed in any one of the preceding claims.