IL44050A - Method and compositions containing halo-acetanilides together with an antidote from the class of halo alkanoylamides for selective control of weeds in corn - Google Patents

Abstract

1454043 Herbicide/antidote composition CIBA-GEIGY AG 24 Jan 1974 [25 Jan 1973] 03293174 Heading A5E A method of selectively combating weeds at a locus comprises (a) applying to the locus before, during or after sowing maize seed therein; or (b) applying to maize seed itself prior to sowing in the locus either simultaneously, or successively in either order: i) a compound of formula I: wherein: R 1 represents a methyl or methoxy group; and ii) a compound of the formula II: wherein R 2 and R 3 , which may be the same or different, each represent an allyl or C 1 -C 4 alkyl group, or together with the nitrogen atom to which they are bonded represent an unsubstituted or 2-methyl substituted 1, 3-oxazolidine ring, the amount of ii) being sufficient to protect the maize seeds or germinating maize shoots from attack by i). Compositions of i) and ii) also are claimed. Compound i) is N-(2'-methoxyethyl)-2, 6-dimethyl-chloroacetanilide or N-(2'- methoxyethyl) - 2 - methyl - 6 - methoxy - chloroacetanilide; typical compounds ii) are N, N-diallyl-dichloroacetamide; N-allyl-N-ethyl-dichloroacetamide and 2, 2-dimethyl-3-dichloroacetyl-1, 3-oxazolidine. Specification 1396941 is referred to. [GB1454043A]

Description

It is known that many herbicides in important of cultivated plants have no, or too little, selective action, i.e. in addition to the weeds to be destroyed they also injure the cultivated plants to a greater or lesser degree.

This applies to most classes of herbicide, e.g. triazines, urea derivatives, carbamates, thiolcarbamates , haloacetani-lides etc.

This property has particularly disadvantageous consequences in large scale crops, such as cereals and maize, and despite successful efforts to find herbicides of good selectivity, this problem has still not been completely satisfactorily solved .

On the other hand, substances have been proposed for pretreating seeds, e.g. for providing cereal and maize seeds with protective layers before sowing in order to make them resistant to specific herbicides. Both the protective agent and the herbicide are very largely species -specific with respect to the cultivated plant. Thus in German Offenlegungsschrift 1.952. 910 and in French patent 2.021.611 (Gulf), the use of 1, 8-naphthalic acid derivatives, oxamic acid derivatives (derivatives of the oxylic monoamide H00C-CO H2) and malonic diamide has been proposed for treating cereal and maize seeds in order to protect these against attack by herbicidal N, N-dialkylated thiocarbamic acid-S-alkyl esters. Earlier, proposals had already been made for treating cereal seeds with the most diverse substances, js!-!&h as hydroxyaminoacetanilide , dichloroxanthenones , hydantoins, isopropyldithiocarbamate salts, N-meth 1-dichlorobenzene-sulphonamide etc., in order to protect the seeds against the action of herbicidal carbamates, such as IPC, CIPC (German patent 1.576.076, US patent 3.131.509 (Gulf).

Of more recent date are publications relating to the treatment of the seeds and shoots of corn and sorghum with Ν,Ν-disubs tituted oxamic acid esters, diallyl prop)Tion-amide, diallyl acetamide, naphthalates etc. in order to protect these against attack by N-methoxymethyl- (2 ' , 6 ' -diethyl-chloroacetanilide) , cf. British patent 1.277.557 (Gulf).

This particular seed treatment before sowing entails substantial economic disadvantages, in particular the expenditure in terms of labour and money involved in the special steps carried out in special mixing devices for the large amounts of seeds which are sown in large-scale crops .

Attempts have therefore already been made to find what are known as safening agents or antidotes which can be applied not to the seeds, but either together with, or before or after, the herbicidal application to the crop area to be sown, or which has already been sown (preemergent treatment) , or after the seeds have germinated (post-emergent treatment) , and which have the same protective effect, i!.^/. they cause the non-selective herbicide to act selectively in that the weeds are damaged as much as possible without any more injury to the cultivated plants. Belgian patent 771.928 and German Offenlegungsschrift (Stauffer) describe such an agent for protecting cereals against the herbicidal action of thiolcarbamates and triazines. Besides these herbicides, this agent contains as antidote halogenated alkanesulphonates of the type X-(CH2)n-0-S02-R wherein X represents a halogen atom, R represents alkyl, haloalkyl, halogen, acetoxy (halo) -alkyl, aryl, and n is a whole number from 1 to 5.

Here too a pronounced species -specificity of the herbicides and the antidote on cereals is evident.

Finally, there has recently appeared a publication (German Offenlegungsschrift 2.218.097, Stauffer) in which, besides a straight forward pretreatment of the seeds with an halogenated alkoylamides , there are also described herbi-cidal agents which contain such haloall^oylamides as anti-dotes.

The majority of the antidotes described and tested therein are used specifically with respect to the active components in the application of herbicidal thiolcarbamates and mixtures thereof with other herbicidal active subs tsif!oes . The emphasis is clearly on antagonising undesirable injury to the crop plants by thiolcarbamates . It is true that this publication does also mention among the herbicides to be protected chloroacetanilides as mixture components and individual active substances. However, the individual tests with such active substances refer only to two herbicides of this type, namely N-methoxymethyl-2, 6-diethyl-chloro-acetanilide ("LASSO") without antidote and with an uneconomic surplus of an antidote in sorghum vulgare, and N-isopropyl-chloroacetanilide ("RAMROD") without antidote and with a surplus of antidote in corn. Despite the surplus of antidote, the result in both cases was far from convincing, the decrease in injury of the crop plant with the antidote moderate, and the ultimate injury determined still considerable (20%) . It is known that, in contradis trinction to other and recent, more active chloroacetanilides, no antidote at all is required when applying these two herbicides to maize.

It is propably for this reason that, despite a vast number of tests, this publication contains no further example with chloroacetanilides as herbicides. Evidently, the appli-cant of German Offenlegungsschrift 2.2128.097 has not realise the exceptionally important fact that other more active chloroacetanilides of different constitution can be conspicu- ously improved in their selective activity against weeds," _:η· cereals and maize by small amounts of some of the antidotes proposed by her, and for this reason has proposed these antidotes with proven success only together with thiolcarba-mates as herbicides.

Whereas certain herbicides of the triazine and phenylurea series are already known for the selective control of weeds in cereals and maize and are commercially available, it has not been possible to avail of more recent haloacetani-lides to the desired extent on account of their generally unsatisfactory selectivity in cereal and maize plantations, since they cause severe injury to these crop plants, which means diminished yield, and still no effective antidote against such halo^entahilides has become known.

The chloroacetanilides of differing constitution which are used according to the present invention, some of which have recently become known (German Offenlegungsschrift 2.305.495, 2.328.340 and 2212268) and form the subject matter of pending patent applications, have the formula I R 44050/2 wherein and each independently represents hydrogen/ Λ a lower alkyl, haloalkyl, alkoxy, alkoxyalkyl or alkylthio radical or a halogen atom, and R represents ap alkyl radical with 1 to 4 carbon atoms which is substituted by carboxy, carboxylic ester, carboxylic amide or cyano radicals, or repre sents an alkoxyalkyl radical of the formula -A-O-R^, wherein A is an alkylene radical with 2 to 4 carbon atoms of which 1 or 2 are in the direct chain, and R^ represents a lower alkyl or alkenyl radical or a cycloalkyl or cycloalkylmethyl radical with 3 to 6 ring carbon atoms, and further, the phenyl nucleus can carr one or two substituents of the definition given for R^ and R2 which are in meta-position to the aniline-nitrogen.

Preferably, herbicidal chloroacetanilides are used wherein, in the above formula I, R, represents hydrogen or an alkyl radical with 1 to 4 carbon atoms, R2 represents an alkyl radical with 1 to 4 carbon atoms, R represents an alkyl radical with 1 to 4 carbon atoms which is substituted by carboxylic ester radicals, or an alkoxyalkyl radical of the formula -A-O-R^* wherein A is an alkylene radical with 2 or 3 carbon atoms, of which 1 or 2 are in the direct chain, and R^ represents an alkyl or alkenyl radical with 1 to 4 carbon atoms, and further, the phenyl nucleus can carry in addition one lower alkyl or alkoxy radical which is in meta-position to the aniline-nitrogen.

The surprising discovery has now been made thai", contrary to the presumptions to be inferred from the literature, it is possible to impart firstjrate protection to maize plants from injury by the above mentioned herbicidal chloroacetanilides by treating the soil with a halogenated an alkraylamide of the formula II as antidote.

In this formula, and each independently represents optionally halogenated alkyl, alkenyl and alkinyl radicals, optionally halogenated alkoxyalkyl and alkenyloxy alkyl radicals, cycloalkyl or cyanoalkyl radicals, and R^ and Rr, together with the adjacent nitrogen atom, can also form a 5- or 7 -membered/heterocyclic ring which can contain in addition a further heteroatom and can be substituted by lower alkyl radicals.

The invention therefore provides a method for the selective control of weeds in maize cultures, which consist in treating the seeds or the crop areas intended for the cultivation of maize in which the seeds are to be sown, or which have been sown, or in which the seeds have already - - germinated, simultaneously or successively, in optional sequence and in an appropriate interval of time, on the one hand with a herbicide of the group of the chloro-acetanilides of the formula I, and on the other with an an antidote of the series of the halogenated allioylamides of the above formula II which protects the germinated crop plants and/or the seeds thereof.

In the formula I of the herbicidal chloroacetanili-des, R represents preferably a lower alkoxyalkyl radical, in particular methoxyethyl, ethoxyethyl, 3-methoxy-propyl (2) etc. Preferred herbicidal active substances of the formula I are N- (2 ' -methoxyethyl) -2 , 6-dimethyl-chloroacet-anilide, N- [3* -methoxypropy1- (2 ' ) ] -2-methyl-6-ethyl-chloro-acetanilide and other 2, 6-dialkylchloroacetanilides with alkoxyalkyl radicals which contain at least two optionally branched hydrocarbon chain members in the alkyl moiety bonder to the nitrogen.

In the formula II of the antidotes, and preferably represent allyl radicals and/or lower alkyl radicals or together form a 1, 3-oxazolidine ring, which in 2-position can be substituted in addition with advantage by methyl groups.

Besides carriers, the agent for selective control of weeds in maize according to the invention contains as herbicidally active component at least one chloroacetanilide - - of the formula I as well as an antidote of the formula lf^^ These agents can be applied in any suitable form. Thus they can be manufactured in known manner by intimately mixing and grinding the herbicidal active substances and the antidote with suitable carriers and/or additives optionally accompanied by the addition of dispersants or solvents.

The conventional process forms are either solid, such as dusts, tracking agents, granules, or liquid solutions, or they take the form of active substance concentrates which can be dispersed in water, such as wettable powders, emulsions, or pastes.

The agent according to the invention is incorporated into the soil either before or after the maize has been sown. But naturally it is also possible to apply first the herbicide and then the antidote to the soil. Finally, it would also be possible to pretreat the seeds themselves first with the antidote and then to sow them in the soil, which has either been treated with the herbicide or in which the herbicide will later be incorporated. It is essential that the addition of the antidote does not impair the herbicidal action of the chloroacetanilide on the weeds.

The amount of antidote used varies between about 0.01 and about 15 parts by weight per part by weight of the haloacetanilide . According to circumstances, i.e. depending on the chloroacetanilide and antidote used and the crop plant, the most suitable ratio for attaining the most ideal activity is ascertained.

Experiments have proved, for example, that by treating sown maize fields with 2 kg/ha of a chloroacetanilide alone there occurred total injury after 3 1/2 weeks; but treatment with a mixture of the same amount of this chloroacetanilide and 0.5 kg/ha of an antidote caused no injury at all to the maize, while weeds such as Sorghum hybridum, Echinoclea and Setaria were just as completely destroyed as without the antidote.

A number of herbicidal chloroacetanilides of the formula I, which can be applied together with the antidotes .. of the formula II, are listed hereinbelow: N- (2 ' -methoxyethyl) -2, 6-dimethyl-chloroacetanilide N- (2 ' -allyloxyethyl) -2, 6-dimethyl-chloroacetanilide N- (2 ' -n-propyloxyethyl) -2, 6-dimethyl-chloroacetanilide N- (2 ' -isopropyloxyethyl) -2, 6-dimethyl-chloroacetanilide N- (2 ' -methoxyethyl) -2-methy1-6-ethy1-chloroacetanilide N- (2 ' -methoxyethyl) -2, 6-diethyl-chloroacetanilide N- (2 ' -ethoxyethyl) -2-methyl-6 -ethyl-chloroacetanilide N- (11 -ethoxycarbonyl-ethyl) -2, 6-dimethyl-chloroacetanilide N- (3 ' -methoxy-propyl- (21 ) -2-meth 1-chloroacetanilide N- (3 ' -methoxy-propyl- (2 ') -2, 6-dimethyl-chloroacetanilide N- (3 ' -methoxy-propyl- (2 ' ) -2-methyl-6-ethyl-chloroacetanilide Ί N- (3 ' -methoxy-propyl- (2 ' ) -2, 6-diethyl-chloroacetanilide >' N-(3 ' -methoxy-propyl- (2 ' ) -2-ethyl-chloroacetanilide N-(2' -ethoxyethyl) -2, 6-diethyl-chloroacetanilide N-(2 ' -n-propoxyethyl) -2-methyl-6-ethyl-chloroacetanilide N-(2* -n-propoxyethyl) -2, 6-diethyl-chloroacetanilide N-(2' -isopropylethyl) -2-methyl-6-ethyl-chloroacetanilide N-chloroacetyl-2, 6-dimethylanilino-acetic acid ethyl and methyl ester β- (N-chloroacetyl-2, 6-dimethylanilino) -propionic acid methyl ester a-(N-chloroacetyl-2-methyl-6-ethyl-anilino) -propionic acid ethyl ester N-(3 ' -methoxy-propyl- (21 ) -2, 3-dimethyl-chloroacetanilide N- (21 -ethoxyethyl) -2-methyl-6-chloro-chloroacetanilide N-(2' -me tho yethyl) -2-methyl-6-chloro-chloroacetanilide N-(2 * -methoxyethyl) -2-methyl-6 -methoxy-chloroacetanilide The above cited, and further, chloroacetanilides of this type and the manufacture thereof have been described in German Offenlegungsschriften 2.212.268, 2.305.495, 2.328. 340 and in Swiss patent applications 15044/72, 1757/73 of CIBA-GEIGY AG.

Suitable antidotes of the formula II are those which come under this formula and are described in part in German. Offenlegungsschrift 2.218.097.

It is conceivable that an antidote which is used in higher rates of application in cereals itself exerts a herbicidal action, but in small amounts antagonises the herbicidal action of the chloroacetanilides on maize.

Preferred antidotes of the formula II are CH2=CH-CH2 \ ) N-C0-CHC1, N,N-diallyl-dichloroacetamide, CH2=CH-CH2 20 nT 1,5036 ) yl-dichloroacetamide CH2-CH2 0 / N -C0-CHC1 N-dichloroacetyl-2, 2-dimethyl- 1, 3-oxazolidine m.p." 119-121° CH. ai.

Very useful as antidotes are also the following dichloro-acetamides which carry at the amide-nitrogen the groups tabulated here inbe low: q N-CO-CHC R - The following tests were carried out to determine' the selective herbicidal action of chloroacetanilides the formula I alone and together with antidotes of the formula II : Pre-emergent application N- (2 ' -methoxyethy1) -2, 6-dimethyl-chloroacetanilide (A) the formula CH was used as herbicidal active substance.

This compound was manufactured by reacting 2, 6-dimethyl-aniline with methoxyacetaldehyde dissolved in benzene in the presence of trimethylamine by boiling to give l-(2'-methoxy-ethylidene-amino) -2, 6-dimethylbenzene (b.p. 58°-61°C/0.1 Torr) , converting this product by hydrogenatio in ethanol with palladium-charcoal to N- (2 ' -methoxyethy1) -2,6-xylidine (b.p. 64°-65°C/0.2 Torr) , and reacting this latter as a suspension together with potassium bicarbonate in benzene with chloroacetyl chloride. 3 Ν,Ν-diyllyl-dichloroacetamide (B) and N -dichloroacetyl- 2, 2-dimethyl-l, 3-ox Λzolidine (C) were used as antidote, both substances described in German Offenlegungsschrift 2.218.097 (Examples 1 and 42), as well as -ethyl-N-ally1-d ichlord-acetamide (D) and N-isopropyl-N-allyl-dichloroacetamide (E) . Aqueous stock broths (suspensions) were prepared from wettable powders based on substances A, B, C, D, and E, and these suspensions were applied both singly and as mixtures, in the indicated concentrations and mixture ratios, immediately after the test plants had been sown in seed dishes in a greenhouse, to the surface of the soil in the dishes. The seed dishes were then kept for 24 days at 22° to 23° C and 50% to 70% relative humidity while appropriately watering the dishes and the emergent plants. The results were evaluated after 13 and 24 days according to a scale of rating from 1-9: 9 = plants not injured (as untreated control) 1 = plants completely withered 2 to 8 = intermediate stages of injury As test plants there were used: crop plant: maize ("Orlea") [Zea] weeds: Sorghum hybridum Echinochloa crus galli Setaria italica Digitaria sanguinalis Bromus tectorum The results are tabulated below.

The amounts in kg/ha are in the following relation to other / units of measurement: 2 1 k /ha = 0.1 g/m = 2 mg per litre of soil, 2 the depth of the t:eed dishes is 5 cm, so that 1 m = 50 litres of soil.

Table III Plant Herbicide A Antidote D Antidote E amount in after 24 days after 24 days kg/ha amcunt in kg/ha amount i kg/ha 0 2 1 0,5 0 2 1 0,5 0 9 9 9 9 9 9 9 9 Maize 0,5 8 9 9 9 8 9 9 9 1,0 (Or la) 3 9 9 9 3 9 9 9 2,0 2 9 9 2 9 8 0 9 9 9 9 9 9 9 9 So ghum 0,5 2 2 2 2 2 2 2 1 hybridurn 1,0 2 2 2 2 2 2 2 2 2,0 . 1 1 1 1 1 1 0 9 9 9 9 9 9 9 9 Echinochloa 0,5 1 1 1 1 1 1 1 1 crus galli 1,0 1 1 1 1 1 1 1 1 2,0 1 1 1 1 1 1 0 9 9 9 9 9 9 9 9 Seta ia 0,5 2 1 1 1 2 1 1 1 italica i»o 1 1 1 1 1 1 1 1 2,0 1 I 1 1 1 1 0 9 : 9 9 9 9 9 9 9 Digitaria 0,5 1 1 1 1 1 1 1 1 sanguinalis 1,0 1 1 1 1 1 1 1 1 2,0 1 1 1 1 1 1 0 9 9 9 9 9 9 9 9 Bromus 0,5 2 2 2 2 2 2 2 2 tectorum 1,0 1 2 1 1 1 1 2 1 2,0 1 1 1 1 1 1 The results show clearly that the crop plant maiae, which is virtually completely destroyed after 13 days using a rate of application of 2 kg/ha of herbicide A alone, suffers no more injviry at all even after 24 days using the same amount of herbicide together with only 1/4 the amount (0.5 kg/ha) of the antidote B, C, D or E, whereas all weeds are just as severely injured as without the antidote. It can even be seen that better results are often obtained with the application of smaller amounts of antidote than with larger ones. No surplus of antidote is therefore necessary and the ratio of antidote to herbicide can be 1:4.

It is advisable in practice, especially in regions with low rainfall, not only to apply the agent according to the invention to the surface of the soil, but to work it into the soil before the crop plants are sown, thus preventing only the perhaps more soluble herbicide from penetrating into the soil when rainfall is slight and the antidote which remains on the surface from not being sufficiently active.

In the above tests, a surface treatment of the soil alone was sufficient to prove clearly an optimum effectiveness of the antidote.

Similarly good results were attained with other herbicidal chloroacetanilides of the formula I and with other antidotes of the formula II.

Claims (12)

CLAIMS :

1. A method for the selective control of weeds in maize, which comprises the use of chloroacetanilides as herb ic ideal active substances, and which consists in treating the seeds or the crop areas intended for sowing, or crop areas for the cultivation of maize which have been sown or in which the seeds have already germinated, simultaneously or successively in optional sequence, on the one hand with a herbicide of the group of the chloroacetanilides of the formula I wherein and R2 each independently represents hydrogen, a lower alkyl, haloalkyl, alkoxy, alkoxyalkyl or alkylthio radical or a halogen atom, and R^ represents an alkyl radical with 1 to 4 carbon atoms which is substituted by carboxy, carboxylic ester, carbcxy amide or cyano radicals, or represents an alkoxyalkyl radical of the formula -A-O-R^ in which A is an alkylene radical with 2 to 4 carbon atoms of which 1 or 2 are in the direct chain and R^ represents a lower alkyl or alkenyl radical or a cycloalkyl or cyclo- alkylmethyl radical with 3 to 6 ring carbon atoms, and the phenyl nucleus can carry in addition 1 or 2 subs tituents of the definition given for and R2 which are in meta- position to the aniline-nitrogen, and on the other hand with an antidote of the series of the alkoylamides of the formula II which protects the seeds or germinated maize shoots and plants- from attack by this herbicide, in which formula II R^ and R^ each independently represents optionally halogenated alkyl, alkenyl and alkinyl radicals, optionally halogenated alkoxyalkyl and alkenyloxyalkyl radicals, cyclo- alkyl or cyanoalkyl radicals, or R^ and R^, together with the adjacent nitrogen atom, can also from a 5- to 7-membered /heterocycle which can contain in addition a further hetero- atom be mono- or polysubs tituted by lower alkyl radicals.

2. A method according to claim 1, which consists in applying the active substance of the formula I and the antidote of the formula II before sowing to the surface of the soil of the crop area to be sown or incorporating them thereinto.

3. A method according to claim 1, which consists in treating the soil intended for sowing with the antidote ; [ of the formula II, then sowing, and after the seeds have been sown and the plants have emerged, applying the herbicide of the formula I.

4. A method according to claim 1, which consists in using as antidote of the formula II a dichloroacetamide of the formula 2^ N-CHC12 (III) R6 wherein represents the allyl radical or a lower alkyl radical.

5. A method according to claim 1, which consists in using as antidote 2, 2-dimethyl-3-dichloroacetyl~l, 3-oxazolidine.

6. A method according to claim 1, which consists in using as herbicide a chloroacetanilide of the formula wherein represents hydrogen, methyl or ethyl, R2 represents methyl or ethyl, A represents an ethylene radical or an ethylene radical which is substituted by methyl, and represents an alkyl radical with 1 to 3 carbon atoms.

7. A method according to claim 6, which consists in using N- (21 -methoxyethyl) -2, 6-dimethyl-chloroacetanilide as herbicidal chloroacetanilide.

8. A method according to claim 7, which consists in using N-allyl-N-ethyldichloroacetamide as antidote for this chloroacetanilide .

9. A selective herbicidal agent for controlling weeds in maize, which, in addition to carriers and/or dispersants, contains as herbiqidally active 1 component at least one chloroacetanilide of the formula I according to claim 1, and, as a protective antidote for maize, an alkoxyamide of the formula II according to claim 1.

10. An agent according to claim 9, which contains as herbicidal component a chloroacetanilide of the formula IV according to claim 6, and, as antidote, a dichloroacetamide of the formula III according to claim 4.

11. An agent according to claim 10, which contains as herbicidal component N-(2' -methoxyethyl) -2, 6-dimethyl-chloroacetanilide, and, as antidote, N,N-diallyl-dichloro-acetamide or N-allyl-N-ethyl-dichloroacetamide .

12. An agent according to claim 9, which contains as herbicidal component N- (2 ' -methoxyethyl) -2, 6-d imethyl-chloro acetanilide, and, as antidote, 2 , 2-dimethyl-3 -d ichloroacetyl 1, 3-oxy/zolidine. For fhtf Applicants