This invention relates to a new herbicidal composition having synergistic activity comprising a mixture of 2-[7-fluoro-3,4-dihydro-3-oxb-4-(2-propyny1)- 2H-l,4-benzoxazin-6-yl]perhydxoimidazo[l,5-a]pyridin- 1,3-one and another selective herbicide and its use for combating weeds in crops.

The herbicidal activity of 2-[7-fluoro-3,4-dihydro-3-oxo-

4-(2-propγnyl)-2H-l,4-benzoxazin~6-yl]perhydro- imidazo[l,5-a]pyridin-l,3-one is already known

(EP 311 135) . This compound has the following chemical structure (I)

It has now been found that herbicidal compositions which comprise, as active components, a mixture of 2-[7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)- 2H-1,4-benzoxazin-6-yl]perhydroimidazo[1,5-a]pyridin- 1,3-one and a herbicide selected from the group consisting of glyphosate (II) , sulfometuron-methyl (III) , imazapyr (IV), 2,4-D (V), dicamba (VI), diuron (VII), oxyfluorfen (VIII) , glufosinate-ammonium (IX) , amitrole (X) and sethoxydim (XI) as well as metribuzin (XII) , linuron (XIII) , acifluorfen (XIV) , lactofen (XV) , fomesafen (XVI) , pendimethalin (XVII) , alachlor (XVIII) , metolachlor (XIX) , trifluralin (XX) , chlorimuron-ethyl (XXI) , imazaguin

(XXII) and imazethapyr (XXIII) , broaden the spectrum of weeds that can be controlled and show an increase in herbicidal activity in comparison with the individual components without losing the selectivity properties in agricultural crops.

Glyphosate is the common name for N-(phosphonomethyl)- glycine; sulfometuron-methyl is the common name or methyl 2-(4 ₁ 6-dimethylpyridin-2-ylcarbamoylsulfa oyl)benzoate; imazapyr is the common name for 2-(4-isopropyl-4-methyl-5- oxo-2-imidazolin-2-yl)-nicotinic acid; 2,4-D is the common name for 2-(4-chloro-2-methyl- phenoxy)acetic acid; dicamba is the common name for 3,6 dichloro-2-methoxy- benzoic acid; diuron is the common name for 3-(3,4-dichlorophenyl)-l,l- dimethylurea; oxyfluorfen is the common name for 2-chloro- α,α,o:-trifluoro-p-tolyl 3-ethoxy-4-nitrophenyl ether; glufosinate ammonium is the common name for ammonium 4-[hydroxy(methyl)phosphinoyl]-DL-homoalaninate; amitrole is the common name for lH-l,2,4-triazol-3- ylamine; sethoxydim is the common name for (±)-(EZ)-2-(l- ethoxyiminobutyl)-5-[2-(ethylthio)propyl]-3-hydroxy- cyclohex-2-enon ; metribuzin is the common name for 4-amino-6-tert.-butyl- 4,5-dihydro-3-methylthio-l,2,4-triazin-5-one; linuron is the common name for 3-(3,4-dichlorophenyl)- 1-methoxy-l-methylurea; acifluorfen is the common name for 5-[2-chloro-4- (trifluoromethyl)phenoxy]-2-nitrobenzoic aci ; lactofen is the common name for (±)-2-ethoxy-l-ethyl- 2-oxoethyl 5-[chloro-4-(trifluoromethyl)phenoxy]-

2-nitrobenzoate; fomesafen is the common name for 5-[2-chloro-

4-(trifluoromethyl)phenoxy]-N-(methylsulfonyl)-2-nitro- benzamide; pendimethalin is the common name for N-(l-ethylpropyl)-

3, -dimethyl-2,6-dinitroaniline; alachlor is the common name for 2-chloro-2 ,6'-diethyl-

N-methoxymethylacetanilide; metolachlor is the common name for 2-chloro-6'-ethyl- 2'-methy1-N-(2-methoxy-1-methylethyl)acetanilide; trifluralin is the common name for 2,6-dinitro-

N,N-dipropyl-4-(trifluoromethyl)aniline; chlorimuron-ethyl is the common name for ethyl

2-(4-chloro-6-methoxypyrimidin-2-ylcarbamoylsulfamoyl)- benzoate; imazaguin is the common name for (±)-2-[4,5-dihydro-

4-methyl-4-(1-methylethyl)-5-oxo-lH-imidazole-2-yl]-

5-ethyl-3-pyridinecarboxylic acid; and imazethapyr is the common name for (±)-2-[4,5-dihydro- 4-methy1-4-(1-methylethyl)-5-oxo-lH-2-yl]-3-quinoline carboxylic acid.

All these herbicides are described in the "Pesticide Manual", ninth edition, 1991, published by the British Crop Protection Council, London.

The combinations of the invention are suitable for the control of important annual and perennial weeds, especially in plantation and permanent crops, such as for example in fruit, wine, citrus, forests and ornamental cultivations, in arable land outside the vegetation time (for example stubble treatment) , as well as in the industrial area including highways and railways. Further uses are for the control of important weeds in a range of crops, such as for example soya beans.

The combination of active ingredients of the invention ca used for example against the following plant species:

Dicotyledonous weeds of the species Sinapis, Lepidiu , Galium, Stellaria, Matricaria, Anthemis, Galinsoga, Chenopodium, Brassica, Urtica, Senecio, Amaranthus, Portulaca, Xanthium, Convolvulus, Ipomoea, Polygonum, Sesbania, Ambrosia, Cirsiu , 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 (= Elymus) , Sagittaria, Monocharia, Fimbristylis, Eleocharis, Ischaemum and Apera.

The combinations of I with II-XI can be applied pre- e ergently, and the combinations of I with XII-XXIII can be applied post-emergently. 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 I) to the other component is generally between 50:1 and 1:100.

The compositions of the invention can also be used in admixture with other active agents for example other plant-protection agents or pesticides, depending on the particular need.

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 1/ha. The agents can be applied using low-volume or ultra-low-volume techniques or in the form of so-called icrogranules.

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: Y

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 tables A-K wer treated post-emergently with the components at the stated rates. The compositions were diluted with 500 litres of water and sprayed evenly over the plants. Two weeks after treatment the herbicidal effect was evaluated.

Table A

Mixtures of I with glyphosate (II)

Rate Herbicidal E ( according

(g/ha) activity (%) to Colby)

Amarant us retro-flexus

( 81 )

( 43 )

( 70 )

8

Table B

Mixtures of I with sulfometuron-methyl (III)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

Component Rate .Herbicidal E (according (g/ha) activity (%) to Colby)

(59)

(68)

(68)

Table C

Mixtures of I with imazapyr (IV)

Rate Herbicidal E (according

(g/ha) activity (%) to Colby)

ςptaria viridis I 1 30

IV 2 80

I + IV 1 + 2 90 (86!

Sorghum alepense

I ⁸ 70

IV 1 20

I + IV 8 + 1 90 (76)

Cvperus esculeπtus

I 4 80

IV 4 10

I + IV 4 + 4 98 (82)

Table D

Mixtures of I with 2,4-D (V)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

(60) (64)

(40) (80)

Amaranthus retroflexus I 70 V

I + V (73) (76)

Table E

Mixtures of I with dicamba (VI)

Rate Herbicidal E (according

(g/ha) activity (%) to Colby)

Sesbania exaltata

I 1 20

VI 25 70

I + VI 1 + 25 90 (76 ⁾

40 60

85 (76)

Table F

Mixtures of I with diuron (VII)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

(80) (80) (34) (91)

VII 25

85 (50)

99 (65)

100 (80)

40

0 5

70 (40) 80 (43)

5 70 97 (72)

Table G

Mixtures of I with oxyfluorfen (VIII)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

(49) (65)

(88)

14

Table H

Mixtures of I with glufosinate-ammonium (IX ⁾

Rate Herbicidal E (according (g/ha) activity (%) to Colby ⁾

(6β;

(36)

Sorghum halepense

50

IX ^° 0

I + IX 50 90 (50)

Sesbania exaltata

I 2 60

IV 80 0

I + IX 2 + 80 98 (60)

Table I

Mixtures of I with amitrole (X)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

Setaria viridis I 4 20

X 200 60

I + X 4 + 200 80 (68!

(30) (33)

(76)

Table K

Mixtures of I with sethoxydim (XI)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

(73)

15 80 95 :β3:

(64)

Experiments

In a greenhouse the plant species shown in tables L-W were treated pre-emergently with the components at the stated rates. The compositions were diluted with 500 litres of water and sprayed evenly over the soil. Two weeks after treatment the herbicidal effect was evaluated.

Table L

Mixtures of I with metribuzin (XII)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

So abohne

(0) (0)

(0) (0)

(5) (5)

(62)

(55) (55)

Table M

Mixtures of I with linuron (XIII)

Rate Herbicidal E (according

(g/ha) activity (%) to Colby)

Soiabohne

(0)

(6) (5)

Amaranthus retroflexus

(20)

(60)

(40)

19

Table N

Mixtures of I with acifluorfen (XIV)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

So abohne

(70) (73)

(58)

(80)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

(76)

D taria ischaemum

(55)

Table O

Mixtures of I with lactofen (XV)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

Soiabohne I 0

5

10

XV 20

I + XV 1 + 20 (o:

2 + 20 (5; 4 + 20 (10]

Amaranthus retroflexus

20 50

(52) (70)

(40) (70)

(50)

Table P

Mixtures of I with fomesafen (XVI)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

Soiabohne

(10) (20) (20)

(28) (36) (36)

(26) (36) (36)

(68) (76)

(8) (77)

Rate Herbicidal E (according

(g/ha) activity (%) to Colby)

Sorghum halepense

I 4 50

XVI 10 10

I + XVI 4 + 10 85 (55)

(65)

Table 0

Mixtures of I with pendimethalin (XVII)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

n abohne

(0) (0) (0)

(0) (0) (0)

(75)

Pnfyqon laoathiflolium

(50)

et f e s

(20)

Table R

Mixtures of I with alachlor (XVIII)

Rate Herbicidal E (according

(g/ha) activity (%) to Colby)

So-iabohne

I

XVIII 50

I + XVIII 4 + 50 (0) 8 + 50 (0)

_P o _l vqonum lapat.hifolium

I - ^> 20

8 80

XVIII 50

I + XVIII 4 + 50 95 (20) 8 + 50 100 (80)

(30) (58)

Table S

Mixtures of I with metolachlor (XIX)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

Soiabohne

0 0

0 0

0 (0) 0 (0)

(0) (0)

(40)

(64)

(68) (72)

Table T

Mixtures of I with trifluralin (XX)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

Soiabohne

I

XX

I + XX

(58) (75)

(83)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

Polv num laoathifolium

(50) (55)

(90) (91)

Table ϋ

Mixtures of I with Chlorimuron-ethyl (XXI)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

So abohπe

I

XXI

I + XXI 8 + (0) 8 + (0)

(43)

(70)

Table V

Mixtures of I with imazaguin (XXII)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

Sn-iabohne

I 0 0

XXII 0 0

I + XXII 0 (0) 0 (0)

0 (0) 5 (0)

(64)

a nth r troflexus

(60)

Polvqonum laoathifolium I ^Z 20

XXII 20

I + XXII 2 + 80 (36)

Table

Mixtures of I with imazethapyr (XXIII)

Rate Herbicidal E (according (g/ha) activity (%) to Colby)

Soiabohne I

XXIII

I + XXIII (0)

(0)

(10)

(0)

(0)

(0)

(10)

(0)

(0)

(0)

(10)

(0)

(0)

(0)

(10) (0)

Ipomoea ourourea

I 8 15

XXIII 8 40

I + XXIII 8 + 8 70 (;g;

f xus

(75) (75)

PnTygoπur" iapa hifolium

70

XXIII 10

I + XXIII 4 + 95 (73)

(50) (50)