Herbicidal compositions

Details Herbicidal compositions Herbicidal compositions

2000-05-19

2002-09-24

Pak, John (Department: 1616)

Plant protecting and regulating compositions

Plant growth regulating compositions

Plural active ingredients

C504S129000, C504S131000, C504S132000, C504S133000, C504S134000, C504S135000, C504S136000, C504S137000, C504S138000, C504S139000, C504S140000, C504S141000, C504S142000, C504S143000, C504S144000, C504S145000, C504S146000, C504S147000, C504S148000, C504S149000

Reexamination Certificate

active

06455470

ABSTRACT:

This invention relates to herbicidal compositions comprising a herbicidal sulfonylurea derivative and at least one co-herbicide selected from a range of co-herbicides. It further relates to the use of the aforesaid herbicidal compositions for controlling undesired vegetation in crops, especially cereal crops.
EP-A-0 477 808 discloses sulfonylurea derivatives of the general formula (I)
wherein Q is —CH═CH— or —S—, R is straight or branched C1-3 alkyl, and X is —OCH, or CH
3
, or an agriculturally acceptable salt thereof. Examples of agriculturally acceptable salts include salts with inorganic bases such as alkali metal (e.g. sodium, potassium, etc.), alkali earth metal (e.g. magnesium, calcium, etc.) and ammonia as well as organic bases such as dimethylamine, triethylamine, pyrrolidine, piperidine, piperazine, morpholine, benzylamine, ethanolamine, and diethanolamine. The said herbicidal sulfonylurea derivatives are said to present advantageous activity against broadleaf weeds and graminaceous weeds without adverse effects on valuable small grain cereal crop particularly wheat.
The aforesaid sulfonylurea derivatives do not readily control all the weed species encountered in small grain cereal crops in practice. More particularly weeds such as, for example:
Alopecurus myosuroides
(black grass)
Avena fatua
(wild oats)
Galium aparine
(bedstraw cleavers)
Lamium purpureum
(red dead nettle)
Matricaria chamomilla
(mayweed)
Stellaria media
(common chickweed)
Veronica persica
(common field speedwell)
are not easily controlled by said derivatives unless relatively high rates are used. These high rates may then be detrimental to the crops and, of course, reduce the commercial value of the sulfonylurea derivatives. Moreover, environmental considerations increasingly require that lower amounts of herbicidally active substances be used in the control of undesired vegetation.
It is known to overcome this type of problem to some extent by the use of herbicidal compositions in which more than one type herbicide is present. Such compositions, however, should preferably still show the advantageous properties of the individual herbicide constituents and display a synergistic effect between them, whilst maintaining selectivity of herbicidal action with respect to the crop. It is, nonetheless, difficult to determine appropriate combinations of herbicides in view of the considerable number of different types of herbicides available and the plurality of individual herbicides within each such type.
The purpose of the present invention is to provide herbicidal compositions comprising a sulfonylurea derivative as defined above and at least one co-herbicide, said compositions having a broader spectrum of weed control than each individual herbicide constituent, whilst retaining the selectivity of herbicidal action of the sulfonylurea derivative constituent.
A further purpose of the present invention is to provide herbicidal compositions which, when applied pre-emergent or post-emergent, display an enhanced and broader spectrum of herbicidal activity than the sulfonyl urea derivatives used alone, whilst retaining the selectivity of action of the herbicidal action of the sulfonylurea derivatives defined above with regard to the crops being treated.
A further purpose of the present invention is to provide a method of controlling the germination and growth of undesired vegetation in a selective manner with regard to crops, e.g. cereal crops, being treated, which comprises applying to the crop, pre- or post-emergent, a composition according to the present invention.
It is surprising that the compositions of the present invention comprising a sulfonylurea herbicide as defined and at least one co-herbicide are particularly efficient in combating a broad spectrum of weeds while still displaying a selectivity of action with respect to the crops. It is further surprising that the compositions of the present invention additionally exhibit synergistic effects.
According to the present invention there are provided herbicidal compositions comprising a sulfonylurea derivative of formula (I) as defined above and at least one co-herbicide selected from:
urea herbicides,
imidazolinone herbicides,
diphenyl ether herbicides,
hydroxybenzonitrile herbicides,
2-(4-aryloxyphenoxy)alkanoic acid herbicides and oxime herbicides,
carbamate and thiocarbamate herbicides,
quaternary ammonium salt herbicides,
triazole herbicides,
phytohormone herbicides, including aryloxyalkanoic acid herbicides, arenecarboxylic acid herbicides, pyridinecarboxylic acid herbicides, and pyridyloxyacetic acid herbicides,
2,6-dinitroaniline herbicides,
amide herbicides, and
anilide herbicides,
in amounts such that the compositions display selectivity of herbicidal action with respect to crops being treated pre- or post-emergent and exhibit synergistic effects when applied at herbicidally effective rates.
Thus, the ratio of the sulfonylurea herbicide to the co-herbicide is, as appropriate, i.e. depending upon the specific herbicides present in the composition according to the invention, from about 1:1 to about 1:150 and the amounts applied are in the ratio of from about 10:30 g/ha to about 25:1500 g/ha.
The above classification of co-herbicides is based upon the classification of herbicides used in “The Pesticide Manual”, ninth edition, published in 1991 by the British Crop Protection Council.
It has been found that the compositions according to the present invention show improved herbicidal efficacy with respect to the sulfonylurea derivative (I) constituent on its own since they do not present the same weaknesses on weed species which are difficult to control by the use of the sulfonylurea derivative alone. Moreover, the range of weeds on which the compositions of the present invention are herbicidally effective is broadened when compared to the use of the respective sulfonylurea herbicide on its own.
Furthermore, the beneficial selectivity of action of the sulfonylurea herbicide constituent with regard to cereals (including, but not limited to, wheat, barley, oats and rye), is not adversely affected.
It is further surprising that the compositions according to the present invention do not simply present an additive herbicidal effect against most of the weeds encountered in monocotyledonous crops, but show a synergistic effect.
As a consequence, the amounts of the individual herbicidally active constituents in the compositions of the present invention which require to be applied to crops can be reduced over the quantities required when they are used alone, whilst maintaining the efficacy of the herbicidal action at the same level. In addition, the compositions even show an acceptable level of activity against weeds where each of the herbicides used individually would be inefficient on its own because the amount used would be too low, thus permitting an increase in the safety margin for sub-optimal applications.
Preferred sulfonylurea derivatives are those according to formula I above in which —R is —C
2
H
5
, —X is —OCH
3
, and Q is —CH═CH— or —S—, i.e. compounds A and B (see Example 1).
Preferred urea herbicides include isoproturon, chlortoluron, metoxuron, linuron, monolinuron, dimefuron and diuron. Isoproturon is particularly preferred.
Preferred imidazolinone herbicides include imazamethabenz-methyl, imazapyr, imazaquin, and imazapyr ammonium. Imazamethabenz-methyl (“ASSERT”™) is particularly preferred.
Preferred diphenyl ether herbicides include bifenox, acifluorfen, fluoroglycofen ethyl, fomesafen, lactofen, and oxyfluorfen. Bifenox is particularly preferred.
Preferred hydroxybenzonitrile herbicides include bromoxynil and ioxynil. Bromoxynil is particularly preferred.
Preferred 2-(4-aryloxyphenoxy)alkanoic acid herbicides include fenoxaprop ethyl, fenoxaprop-P-ethyl (“PUMA”™), fluazifop-P, fluazifop-butyl, haloxyfop-methyl, haloxyfop-etotyl, isoxapyrifop, propaquizafop-ethyl, quizalofop-ethyl, quizalofop-P-ethyl, and diclofop-methyl.
Preferred carbamate/thiocarbamate herbicides include tri-allate, di-allate, barban, dimepiperate, mol

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