Plant protecting and regulating compositions – Plant growth regulating compositions – Plural active ingredients
Reexamination Certificate
1997-08-08
2001-11-13
Pak, John (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Plural active ingredients
C504S130000, C504S133000, C504S135000, C504S136000, C504S138000, C504S145000, C504S146000
Reexamination Certificate
active
06316387
ABSTRACT:
Synergistic active compound combinations for controlling harmful plants in crops of useful plants.
The invention relates to the field of crop protection agents, and in particular to combinations of groups of active compounds having different modes of action and types of activity, which are outstandingly suitable for use against harmful plants in crops of useful plants.
In many crops of useful plants, grasses are undesirable competitors which can be controlled only with considerable difficulty and at high costs. They germinate and grow in the soil over prolonged periods of time and can therefore only be effectively controlled with herbicides having foliar and soil action.
Examples of important weed grasses which occur in crops of useful plants all over the world and which are of high economic importance are:
Alopecurus myosuroides, Avena fatua and other forms of wild oats, Lolium spp., Phalaris spp., Setaria spp., Echinochloa spp., Poa spp., Bromus spp., Elymus repens, Sorghum spp. and others such as, for example, Agrostis, Panicum, etc.
It has been known for long that compounds from the group of the 1,2,4-triazinones, the (het)aryloxyphenoxypropionates and the cyclohexanedione oximes have excellent herbicidal activity, even if their preferred application in different crops takes place at in some cases considerably different application rates.
EP-A-0 614 608 describes synergistic herbicidal compositions for controlling slender foxtail which comprise certain combinations of (het)aryloxyphenoxypropionates and herbicides of other types of action. These described compositions are generally well suited for controlling grasses such as wild oats (Avena fatua) or slender foxtail (Alopecurus myosuroides) or weeds such as common chickweed (Stellaria media) in crops of cereals.
The compounds of the group of the 1,2,4-triazinones are known as selective systemic herbicides which act as inhibitors of photosynthesis and which are taken up predominantly via the roots, but also via the leaves. Hitherto, the herbicide metribuzin could be used in cereals and maize only at limited application rates; higher dosages, in particular on light soils and at high levels of precipitation, are not fully tolerated. On the other hand, metribuzin is an agent which is widely used in many countries in crops such as soybeans and potatoes. Higher dosages, as they are generally needed in cereals and maize for controlling grasses, are often not acceptable since they are not fully selective. Generally, the activity against many grasses is not satisfactory, so that in practice mixtures with other soil herbicides such as, for example, alachlor, metolachlor or dimethenamide are used to control the grasses with better effectiveness.
Herbicides from the group of the(het)aryloxyphenoxypropionic acids and also of the cyclohexanedione oximes are in each case acetyl-CoA-carboxylase inhibitors and are particularly easily taken up via the leaves. They are used by the post-emergence method for controlling grasses in all important crops. Some of the important ones, such as diclofop, fenoxaprop, clodinafop and tralkoxydim, can also be used for controlling grasses in cereals, compositions based on fenoxaprop and clodinafop generally being used in combination with safeners, i.e. herbicidal antidotes.
Recently, some of these grasses have become difficult to control since, owing to the repeated application of herbicidally active compounds, resistant forms, or forms which have a significantly reduced susceptibility towards these groups of active compounds, have emerged. In this case, it is no longer possible to use the corresponding herbicides at application rates which ensure the desired herbicidal effect without causing considerable damage to the crops. Depending on the type of grass and herbicide, the resistance increase can vary considerably and can be so high that even amounts of 2 to 10 times the normal application rate are no longer sufficiently effective.
In biological greenhouse trials and free-range trials, it has now been found that certain, partly novel, herbicidally active compound combinations exhibit surprisingly high synergistic activities which far exceed expectations, and that they are at the same time very well tolerated by the crops. Additionally, it is possible to selectively control harmful grasses of economic importance which could hitherto not be controlled by any of the individual active compounds by employing the present herbicidal combinations. This also applies to grasses which have become resistant against one of the active compounds in question and which have therefore caused new problems in agricultural practice. Using the combinations according to the invention, it is once again possible to control even those species efficiently. Owing to their properties with respect to their spectrum of activity and their effectiveness, which are highly superior to the known herbicidal compositions, it is possible to employ the novel synergistic active compound combinations at considerably reduced application rates, so that, in addition to the advantage of improved cultivation of the useful plants, further economic and ecologic advantages can be obtained.
The present invention, accordingly, provides for the use of a herbicidal combination for the selective control of harmful grasses from the group consisting of Phalaris spp. and Lolium spp. in crops of useful plants, the combination comprising
A) one or more compounds from the group of the 1,2,4-triazinones and
B) one or more compounds from the group consisting of (het)aryloxyphenoxypropionic acid derivatives and cyclohexanedione oximes.
Examples of suitable compounds are listed below (cf. The Pesticide Manual, 10th. Edition, British Crop Protection Council, 1994):
compounds of type A: metribuzin and metamitron;
compounds of type B (acetyl-CoA-carboxylase inhibitors):
(het)aryloxyphenoxypropionates, for example fenoxaprop, fenoxaprop-P, clodinafop, haloxyfop, quizalofop, quizalofop-P, diclofop, fluazifop, fluazifop-P, propaquizafop, isoxapyrifop and the (C
1
-C
4
)-alkyl esters, (C
2
-C
4
)-alkenyl esters or (C
2
-C
4
)-alkinyl esters of the abovementioned herbicides, and cyclohexanedione oximes, for example alloxydim, sethoxydim, cloproxydim, cycloxydim, clethodim and tralkoxydim.
Preference is given to the use of those herbicidal combinations according to the invention which comprise as compound A) metribuzin and B) one or more compounds of the group consisting of fenoxaprop, fenoxaprop-P, clodinafop, haloxyfop, quizalofop, quizalofop-P, diclofop, fluazifop-P, propaquizafop, isoxapyrifop and esters thereof and tralkoxydim; very particular preference is given to the use of the abovementioned compositions in crops of cereals.
Some of the herbicide combinations which can be used according to the invention are already known; their suitability for use against the abovementioned grasses which have developed resistance against some of the herbicides has not been known.
Known combinations of herbicides are:
a) metribuzin in combination with fenoxaprop-(P) ester [see the abovementioned EP-A-614608]
b) metribuzin in combination with the cyclohexanedione herbicide 5-(1-methylthiocyclopropan-1-yl)-2-[1-(trans-3-chloroallyloximino)-propionyl]cyclohexane-1,3-dione [cf. EP-A-487454]; the combination is recommended for controlling Digitaria sanguinalis, Sorghum halepense, Alopecurus myosuroides, Setaria faberi and Echinochloa crusgalli in dicotyledonous cultures such as soybean, sugar beet, rapeseed, cotton and vegetables.
c) metribuzin in combination with diclofop-methyl; the action on Avena fatua [Chem. Abstracts 94:97882r] and the selective action on Eleusine indica in Cynodon spp. (Bermudagrass) [Chem, Abstracts 115:177353m] is described.
d) metribuzin in combination with sethoxydim or fluazifop-P-butyl [Chem. Abstracts 116:2237v]; the action on Amaranthus retroflexus, Eleusine indica and Digitaria sanguinalis is described.
e) metribuzin in combination with fluazifop-P-butyl, haloxyfop-methyl, quizalofop-ethyl or setho
Bieringer Hermann
Grüninger Kurt
Huff Hans Philipp
Wolff Jean-Michel
Frommer & Lawrence & Haug LLP
Hoechst Schering AgrEvo GmbH
Pak John
LandOfFree
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