WO2009010475A2

WO2009010475A2 - A method for controlling aquatic weeds

Info

Publication number: WO2009010475A2
Application number: PCT/EP2008/059126
Authority: WO
Inventors: Joseph Zawierucha; Christopher Todd Horton
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2007-07-17
Filing date: 2008-07-11
Publication date: 2009-01-22
Anticipated expiration: 2010-01-17
Also published as: WO2009010475A3

Abstract

The invention relates to a method for controlling aquatic weeds, which comprises applying a herbicidally effective amount of a VLCFA (very-long-chain fatty acid) biosynthesis inhibitor to the water body of aquatic weeds and/or their aqueous habitat containing seeds or other propagating organs of said aquatic weeds.

Description

A method for controlling aquatic weeds

Description

This invention belongs to the field of agricultural chemistry and provides to the art a method for controlling aquatic weeds, specifically Hydrillia verticillata.

Aquatic weeds often have detrimental effects on the environment or the economics of waters and wetlands, for example in wet areas such as parts of Florida. Aquatic weeds for example clog waterways, plug up water-handling equipment or endanger the ecological balance. Inter alia, they affect fishing, navigation, transport, drinking water quality, swimming and watersports. The economic impact for control and management in general and in particular in recreational areas is estimated to be in the millions of dollars. Therefore, the development of herbicides effective against aquatic weeds is important.

A typical representative for inventively controlled aquatic weeds is hydrilla, which is known as a submersed, very prolific, mat forming species, possibly dominating the aquatic system that it is present in. High densities of hydrilla interfere with various water uses as outlined above. A typical representative is Hydrilla verticillata.

The control of certain aquatic weeds is discussed in the following art.

Generally, aquatic weeds and herbicidal or biological methods for controlling them are known, for example from L.W.J. Anderson, Pest Manag. Sci., 2003, 59, 801-813 or Netherland M. D., Getsinger K. D. and Stubbs D. R., Outlooks Pest Man., 2005, 16(3), 100-105 orJ. E. Gallagher and WT. Haller, Rev. Weed Sci., 1990, 5, 1 15-192.

One of the major herbicides used for controlling aquatic weeds such as Hydrilla verticillata is fluridone (1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1 H)-pyridinone).

However, it became apparent that a number of new biotypes of hydrilla have developed increased tolerance or even resistance to fluridone. Therefore, there is a continuous demand to further develop efficient herbicides for controlling aquatic weeds in general. Notably, the need for an herbicide to control hydrilla species, in particular Hydrilla verticillata, specifically their biotypes being tolerant or resistant to the herbicide fluridone, is warranted.

Inhibitors of very-long-chain fatty acid synthesis (VLCFA-inhibitors (as described by the Herbicide Resistance Action Committee "HRAC"), inhibitors the biosynthesis of fatty acids with more than eighteen carbon atoms) are a group of well known herbicides, such as chloroacetamides and chloroacetanilides, which are predominantly used in maize cultures.

It has now been found that inhibitors of very-long-chain fatty acids biosynthesis (VLCFA- inhibitors; compound(s) I) or agriculturally acceptable salts, esters or amides thereof effectively provide growth suppression or control of aquatic weeds in general and of hydrilla species in particular.

The present invention therefore relates to a method for controlling aquatic weeds, which comprises applying a herbicidally effective amount of at least one VLCFA-inhibitor (compound(s) I) or an agriculturally acceptable salt, ester or amide thereof to aquatic weeds and/or their aqueous habitat containing seeds or other propagating organs of said aquatic weeds.

The term "controlling" in this context means exhibiting aquatic-herbicidal action, i.e. the growth of at least one aquatic weed species is reduced or suppressed concerning number and/or size of its plants yielding in e.g. limited growth or death of the weeds. A weed generally is an unwanted plant. A plant is described as unwanted if its presence is not wanted in a particular place.

Aquatic weeds are unwanted plants that have adapted to living in or on aquatic environments. This includes water as well as water-saturated soil. Thus, their habitat means the plants' living space including but not limited to water environment like fresh water or salt water sources, either as moving water or still water. Examples thereof are lakes, rivers, streams, wetlands, ponds, creeks, swamps, canals, reservoirs, and ditches. Other examples are marine water environments like oceans, seas, gulfs, and straits. Examples of saturated soils are water-saturated fields, in particular paddy fields.

Aquatic weeds can be further distinguished as follows:

"Emersed aquatic weeds" grow standing out of the water or in water-saturated soil. A typical representative for an emersed species is alligatorweed (Alternanthera philoxeroides). Further examples are cattails, bulrushes, and purple loosestrife.

"Submersed aquatic weeds" grow with all or most of their vegetative tissue below the water surface. Typical representatives for submersed species are hydrilla (Hydrilla) and milfoil (Myriophyllum). Further examples include sego pondweed, southern naiad, and Egeria. "Floating aquatic weeds" float on the water surface. Examples are duckweeds, water- hyacinth, water-lettuce, water-fens, and water-lilies. "Algae" are considered 'primitive' plants but often are incorporated into the generic group of aquatic weeds.

One preferred embodiment of the invention relates to a method for controlling submersed aquatic weeds, which comprises applying a herbicidally effective amount of a VLCFA- inhibitor to submersed aquatic weeds and/or their aqueous habitat containing seeds or other propagating organs of said submersed aquatic weeds.

In case the inventive method for controlling submersed aquatic weeds is applied in the presence of emersed aquatic weeds and/or floating aquatic weeds and/or algae, (simultaneous) control of emersed aquatic weeds and/or floating aquatic weeds and/or algae may (also) take place.

A particularly preferred embodiment of the invention relates to a method for controlling submersed aquatic weeds, which comprises applying a herbicidally effective amount of a VLCFA-inhibitor to submersed aquatic weeds and/or their aqueous habitat containing seeds or other propagating organs of said submersed aquatic weeds, wherein the submersed aquatic weeds are tolerant and/or resistant to the herbicide fluridone.

In another particularly preferred embodiment of the invention, the aquatic weed to be controlled is a Hydrilla species, preferentially Hydrilla verticillata.

In a most particularly preferred embodiment of the invention, the aquatic weed to be controlled is Hydrilla verticillata, wherein Hydrilla verticillata is tolerant and/or resistant to the herbicide fluridone.

In a further embodiment of the invention, there is provided the use of a VLCFA-inhibitor - in particular the compounds defined below - for controlling aquatic weeds, preferably sub- mersed aquatic weeds, more preferred Hydrilla species, most particularly Hydrilla verticillata.

Preferred is the use where the aquatic weed, preferably the submersed aquatic weed, more preferred a Hydrilla species, most particularly preferred Hydrilla verticillata, is tolerant and/or resistant to the herbicide fluoridone.

The VLCFA-inhibitor is preferably an alkanamide (acetamide) (l-a), a chloroacetamide (l-b), an oxyacetamide (l-c), a tetrazolinone (l-d), or is selected from anilophos, cafenstrole, indanofan and piperophos (l-e) (the chemical classification following The Pesicide Manual, 14^th ed., British Crop Protection Council, Farnham 2006).

Preferred alkanamides (l-a) are diphenamid, naproanilide and naproamide.

Preferred chloroacetamides (l-b) are acetochlor, alachlor, butachlor, dimethachlor, dimethenamid, dimethenamid-P, metazachlor, metolachlor, S-metolachlor, pethoxamid, pretilachlor, propachlor, propisochlor and thenylchlor.

Preferred oxyacetamides (l-c) are flufenacet and mefenacet.

A preferred tetrazolinone (l-d) is fentrazanone.

Preferred as VLCFA-inhibitors are chloroacetamides (l-b). Particularly preferred are dimethenamid and dimethenamid-P.

Dimethenamid (l-b-1 ) is (RS)-2-chloro-N-(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl) acetamide

Dimethenamid-P (l-b-2) is (S)-2-chloro-N-(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl) acetamide

The compounds (l-a) to (l-e) are known from the literature, e.g. from the respective published patent applications or by their common names from The Compendium of Pesticide Common Names (http://www.hclrss.demon.co.uk/index.html) or The Pesticide Manual, 14^th edition, 2006. They are also commercially available, e.g. dimethenamid and dimethenamid-P from BASF SE, Ludwigshafen, Germany.

In one preferred embodiment of the invention, the VLCFA-inhibitor is applied as sole active ingredient. In another preferred embodiment, the VLCFA-inhibitor is applied in combination with one or more other herbicide(s), from the group of compounds (II) - as defined below - or an agriculturally acceptable salt, ester or amide thereof.

Preferred embodiments of the invention relate to combinations of each one of compounds l-a, l-b (l-b-1 and/or l-b-2), l-c, and l-d, resp., with one of the compounds Il - as defined below - and their use.

In the following, the VLCFA-inhibitors (I) and/or compound(s) (II) and/or their respective agriculturally acceptable salts, esters or amides will be designated as active ingredients.

Suitable compound(s) (II) are selected from the following classes: acetyl-CoA carboxylase inhibitors (ACC), acetolactate synthase inhibitors (ALS), amides, auxin herbicides, auxin transport inhibitors, carotenoid biosynthesis inhibitors, enolpyruvylshikimate 3-phosphate synthase inhibitors (EPSPS), glutamine synthetase inhibitors, lipid biosynthesis inhibitors, mitosis inhibitors, protoporphyrinogen IX oxidase inhibitors, photosynthesis inhibitors, synergists, growth substances, cell wall biosynthesis inhibitors and a variety of other herbicides.

Suitable compounds (II) are, as acetyl-CoA carboxylase inhibitors (ACC), for example cyclohexenone oxime ethers, phenoxyphenoxypropionic esters or arylaminopropionic acids. The acetolactate synthase inhibitors (ALS) include, inter alia, imidazolinones, pyrimidyl ethers, and sulfonamides orsulfonyl ureas. Relevant auxin herbicides are, inter alia, pyridine carboxylic acids, 2,4-D or benazolin. Lipid biosynthesis inhibitors which are used are, inter alia, thioureas, benfuresate or perfluidone. Suitable mitosis inhibitors are, inter alia, carbamates, dinitroanilines, pyridines, butamifos, chlorthal-dimethyl (DCPA) or maleic hydrazide. Examples of protoporphyrinogen IX oxidase inhibitors are, inter alia, diphenyl ethers, oxadiazoles, cyclic imides or pyrazoles. Suitable photosynthesis inhibitors are, inter alia, propanil, pyridate, pyridafol, benzothiadiazinones, dinitrophenols, dipyridyl- enes, ureas, phenols, chloridazon, triazine, triazinone, uracils or biscarbamates. The synergists are, inter alia, oxiranes. Examples of suitable growth substances are aryloxyalkanoic acids, benzoic acids or quinolinecarboxylic acids. The group "various other herbicide" is to be understood as meaning, inter alia, the classes of the active ingredients dicloropropionic acids, dihydrobenzofurans, phenylacetic acids and individual herbicides mentioned below whose mechanism of action is not yet (fully) understood.

Other suitable compound(s) (II) are active ingredients selected from the group of the amides, auxin transport inhibitors, carotenoic biosynthesis inhibitors, enolpyruvylshikimate 3-phosphate synthase inhibitors (EPSPS), glutamine synthetase inhibitors and cell wall synthesis inhibitors.

More specific examples of herbicides (compound(s) II), which can be used in combination with a VLCFA-inhibitor, are:

11-1 acetyl-CoA carboxylase inhibitors (ACC), for example

cyclohexenone oxime ethers, such as alloxydim, clethodim, cloproxydim, cycloxydim, sethoxydim, tralkoxydim, butroxydim, clefoxydim (=profoxydim) or tepraloxydim; phenoxyphenoxypropionic esters, such as clodinafop-propargyl, cyhalofop-butyl, diclofop-methyl, fenoxaprop-ethyl, fenoxaprop-P-ethyl, fenthiapropethyl, fluazifop- butyl, fluazifop-P-butyl, haloxyfop-ethoxyethyl, haloxyfop-methyl, haloxyfop-P- methyl, isoxapyrifop, metamifop, propaquizafop, quizalofop-ethyl, quizalofop-P- ethyl or quizalofop-tefuryl; or arylaminopropionic acids, such as flamprop-methyl or flamprop-isopropyl; or keto-enols such as pinoxaden;

II-2 acetolactate synthase inhibitors (ALS), selected from • imidazolinones, selected from imazapyr, imazaquin, imazamethabenz-methyl

(imazame), imazapic, imazethapyr and imazamethapyr; pyrimidyl ethers, such as pyrithiobac-acid, pyrithiobac-sodium, bispyribac-sodium, pyriminobac-methyl, pyriftalid or pyribenzoxym; triazolopyrimidines, such as florasulam, flumetsulam, metosulam, penoxsulam, diclosulam, or cloransulam-methyl; sulfonylureas, such as amidosulfuron, azimsulfuron, bensulfuron-methyl, chlorimuron-ethyl, chlorsulfuron, cinosulfuron, cyclosulfamuron, ethametsulfuron- methyl, ethoxysulfuron, flazasulfuron, flucetosulfuron, flupyrsulfuron-methyl-Na, foramsulfuron, halosulfuron-methyl, imazosulfuron, mesosulfuron, metsulfuron- methyl, nicosulfuron, orthosulfamuron, oxasulfuron, primisulfuron-methyl, prosulfuron, pyrazosulfuron-ethyl, rimsulfuron, sulfometuron-methyl, thifensulfuron- methyl, triasulfuron, tribenuron-methyl, triflusulfuron-methyl, trifloxysulfuron, tritosulfuron, sulfosulfuron, or iodosulfuron; sulfonylaminocarbonyltriazolinones, such as thiencarbazon, flucarbazone or propoxycarbazone-sodium; or sulfonamides, such as pyrimisulfan:

11 —3 amides, selected from allidochlor (CDAA), benzoylprop-ethyl, bromobutide, chlorthiamid, diphenamid, etobenzanid (benzchlomet), fluthiamide, fosamin or monalide;

11-4 auxin herbicides, for example pyridinecarboxylic acids, such as aminopyralid, fluroxypyr, triclopyr, clopyralid or picloram; or

2,4-D or benazolin;

11-5 auxin transport inhibitors, for example naptalame or diflufenzopyr;

II-6 carotenoid biosynthesis inhibitors, for example beflubutamid, clomazone (dimethazone), diflufenican, fluorochloridone, fluridone, ketospiradox, flurtamone, norflurazon, amitrol, or picolinafen;

II-7 enolpyruvylshikimate-3-phosphate synthase inhibitors (EPSPS), for example glyphosate or sulfosate;

II-8 glutamine synthetase inhibitors, for example bilanafos (bialaphos) or glufosinate-ammonium;

II-9 lipid biosynthesis inhibitors, selected from thiocarbamates, such as butylate, cycloate, di-allate, dimepiperate, EPTC, esprocarb, molinate, orbencarb, pebulate, prosulfocarb, thiobencarb (benthiocarb), thiocarbazil, tri-allate or vernolate; or • isoxazolines, such as pyroxasulfon (KIH-485) benfuresate, ethofumesate, cafenstrole or perfluidone;

11-10 mitosis inhibitors, for example carbamates, such as asulam, carbetamid, chlorpropham, pronamid (propyzamid), or propham; dinitroanilines, such as benefin, butralin, dinitramin, ethalfluralin, fluchloralin, oryzalin, pendimethalin, prodiamine or trifluralin; pyridines, such as dithiopyr or thiazopyr; or butamifos, chlorthal-dimethyl (DCPA) or maleic hydrazide;

11-1 1 protoporphyrinogen IX oxidase inhibitors, selected from diphenyl ethers, selected from bifenox, chlornitrofen (CNP), ethoxyfen, fluorodifen, fomesafen, furyloxyfen, nitrofen, nitrofluorfen or oxyfluorfen; oxadiazoles, such as oxadiargyl or oxadiazon; cyclic imides, such as azafenidin, butafenacil, carfentrazone-ethyl, cinidon-ethyl, flumiclorac-pentyl, flumioxazin, flumipropyn, flupropacil, fluthiacet-methyl, sulfentrazone or thidiazimin; or pyrazoles, such as pyraflufen-ethyl (ET-751 ), fluazolate (JV 485) or nipyraclofen; • pyridazinones, such as flufenpyr-ethyl; or triazolones, such as benzcarbazon;

11-12 photosynthesis inhibitors, for example propanil, pyridate or pyridafol; • benzothiadiazinones, such as bentazone; dinitrophenols, for example bromofenoxim, dinoseb, dinoseb-acetate, dinoterb or

DNOC; dipyridylenes, such as cyperquat-chloride, difenzoquat-methylsulfate, diquat or paraquat-dichloride; • ureas, such as chlorbromuron, chlorotoluron, difenoxuron, dimefuron, diuron, ethidimuron, fenuron, fluometuron, isoproturon, isouron, linuron, methabenz- thiazuron, methazole, metobenzuron, metoxuron, monolinuron, neburon, siduron ortebuthiuron; phenols, such as bromoxynil or ioxynil; • chloridazon; triazines, such as ametryn, atrazine, cyanazine, desmetryn, dimethamethryn, hexazinone, prometon, prometryn, propazine, simazine, simetryn, terbumeton, terbutryn, terbutylazine or trietazine; triazinones, such as metamitron or metribuzin; • uracils, such as bromacil, lenacil or terbacil; or biscarbamates, such as desmedipham or phenmedipham; triazolinones, such as amicarbazone

11-13 synergists, for example • oxiranes, such as tridiphane;

11-14 growth substances, selected from aryloxyalkanoic acids, such as 2,4-DB, clomeprop, dichlorprop, dichlorprop-P (2,4-DP-P), MCPA, MCPB, mecoprop, or mecoprop-P; and • benzoic acids, such as chloramben or dicamba

11-15 cell wall synthesis inhibitors, for example isoxaben, flupoxam or dichlobenil; 11-16 various other herbicides, for example dichloropropionic acids, such as dalapon; phenylacetic acids, such as chlorfenac (fenac); or aziprotryn, barban, bensulide, benzthiazuron, benzofluor, buminafos, buthidazole, buturon, chlorbufam, chlorfenprop-methyl, chloroxuron, cinmethylin, cumyluron, cycluron, cyprazine, cyprazole, dibenzyluron, dipropetryn, dymron, eglinazin-ethyl, endothall, ethiozin, fluorbentranil, isocarbamid, isopropalin, karbutilate, mefluidide, monuron, napropamide, napropanilide, nitralin, oxaciclomefone, phenisopham, piperophos, procyazine, profluralin, pyributicarb, secbumeton, sulfallate (CDEC), terbucarb, triaziflam, triazofenamid ortrimeturon.

The herbicidally active ingredients from amongst groups 11-1 to 11-16 are described, for example, in The Compendium of Pesticide Common Names,

(http://www.alanwood.net/pesticides/); Farm Chemicals Handbook 2000 Vol. 86, Meister Publishing Company, 2000; B. Hock, C. Fedtke, R. R. Schmidt, Herbizide, Georg Thieme Verlag, Stuttgart 1995; W. H. Ahrens, Herbicide Handbook, 7^th Edition, Weed Science Society of America, 1994; The Pesticide Manual, 14^th edition, 2006 and K. K. Hatzios, Herbicide Handbook, Supplement to 7^th Edition, Weed Science Society of America, 1998.

The categorization of the herbicides according to their mode of action is based on current understanding. If a herbicide acts by more than one mode of action, this substance was assigned to only one mode of action.

In the inventive method, combinations of the VLCFA-inhibitors (I) and compounds (II) can be applied. Preference is given to combinations comprising the VLCFA-inhibitors (I) and at least one, preferably exactly one, herbicidally active compound (II) selected from the group consisting of II-2: ALS inhibitors, preferably imazamox; II-4: auxin herbicides; II-5: auxin transport inhibitors, preferably diflufenzopyr; II-6: bleacher herbicides, preferably fluridone;ll-14: growth substances, and 11-16: endothall.

In binary compositions which comprise a VLCFA-inhibitor (I) and at least one compound (II), the weight ratio of the compounds (I) and (II) is usually in the range from 1 :500 to 10:1 , preferably in the range from 1 :100 to 10:1 , in particular in the range from 1 :50 to 10:1 and particularly preferably in the range from 1 :25 to 5:1.

If the VLCFA-inhibitor (I) and/or the compounds 11-1 to 11-16 and/or their respective agriculturally acceptable salt, ester or amide are capable of forming geometrical isomers, for example E/Z isomers, it is possible to use both the pure isomers and mixtures thereof in the compositions according to the invention. If the VLCFA-inhibitor (I) and/or the compounds 11-1 to 11-16 and/or their respective agriculturally acceptable salt, ester or amide have one or more centers of chirality and, as a consequence, are present as enantiomers or diastereomers, it is possible to use both the pure enantiomers and diastereomers and their mixtures in the compositions according to the invention.

If appropriate, both VLCFA-inhibitors (I) and compounds 11-1 to 11-16 may be present in form of their agriculturally acceptable salt, ester or amide. Suitable salts, esters, and amides are, in general, those, which do not adversely affect the herbicidal action of the active ingredients.

Suitable cations are the ions of the alkali metals, preferably of lithium, sodium and potassium, of the alkaline earth metals, preferably of calcium and magnesium, and of the transition metals, preferably of manganese, copper, zinc and iron, furthermore ammonium and substituted ammonium in which one to four hydrogen atoms are replaced by C1-C4- alkyl, hydroxy-Ci-C4-alkyl, Ci-C4-alkoxy-Ci-C4-alkyl, hydroxy-Ci-C4-alkoxy-Ci-C4-alkyl, phenyl or benzyl, preferably ammonium, methylammonium, isopropylammonium, dimethylammonium, diisopropylammonium, trimethylammonium, tetramethylammonium, tetraethylammonium, tetrabutylammonium, 2-hydroxyethylammonium, 2-(2-hydroxyethoxy)eth-1- ylammonium, di(2-hydroxyeth-1 -yl)ammonium, benzyltrimethylammonium, benzyltriethylammonium, furthermore phosphonium ions, sulfonium ions, preferably tri(Ci-C4-alkyl)sulfonium such as trimethylsulfonium, and sulfoxonium ions, preferably tri(Ci-C4-alkyl)sulfoxonium.

For those compounds 11-1 to 11-16, which may form cationic salts, suitable anions are primarily chloride, bromide, fluoride, iodide, hydrogen sulfate, methyl sulfate, sulfate, dihydrogen phosphate, hydrogen phosphate, nitrate, dicarbonate, carbonate, hexafluorosilicate, hexafluorophosphate, benzoate and the anions of Ci-C4-alkanoic acids, preferably formate, acetate, propionate and butyrate.

Suitable esters are alkly-, alkoxyalkyl-, allyl-, propargyl- and oxetan-3-ylesters, preferably Ci-Cio-esters, for example methyl-, ethyl-, propyl-, isopropyl-, butyl-, isobutyl-, pentyl-, mexyl- (= 1 -methyl-hexyl) or isoctyl- (= 2-ethylhexyl) ester, Ci-C4-alkoxyethyl-esters, for example methoxyethyl-, ethoxyethyl- or butoxyethyl-ester, allylesters, proparyglesters and oxetan-3-ylesters.

Suitable amides are unsubstituted amides, alkyl- and dialkyl-amides as well as anilides, preferably Ci-C4-alkyl-amides, for example methyl- or ethyl-amide, di(Ci-C4-alkyl)-amides, for example dimethyl- or diethyl amide, or anilides, preferably anilide itself or 2-chloro-anilide. For application, ready-to-use preparations in the form of crop protection products can be employed. The VLCFA-inhibitor and optionally one or more compound(s) Il may be present in suspended, emulsified or dissolved form and can be formulated jointly or separately. The application forms depend entirely on the intended use.

The preparations can be applied, for example, in the form of directly sprayable aqueous solutions, powders, suspensions, also highly-concentrated aqueous, or other suspensions or dispersions, pastes, dusts, materials for spreading or granules, by means of spraying, atomizing, dusting, broadcasting or watering. The use forms depend on the intended use; preferably, they should ensure the finest possible distribution of the active compounds. Coarser distribution might be desired e.g. when a different activity is to be achieved. Depending on the form in which the ready-to-use preparations are present, they comprise one or more liquid or solid carriers, if appropriate surfactants or sinking agents and if appropriate further auxiliaries which are customary for formulating crop protection products. The person skilled in the art is sufficiently familiar with the recipes for such formulations.

Suitable inert additives with carrier function are essentially: oils of vegetable or animal origin, aliphatic, cyclic and aromatic hydrocarbons, e.g. paraffins, tetrahydronaphthalene, alkylated naphthalenes and their derivatives, alkylated benzenes and their derivatives, alcohols such as methanol, ethanol, propanol, butanol and cyclohexanol, ketones such as cyclohexanone, strongly polar solvents, e.g. amines such as N-methylpyrrolidone, and water.

Examples of solid carriers are mineral earths such as silica gels, silicates, talc, kaolin, attaclay, limestone, lime, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate, magnesium sulfate, magnesium oxide, ground synthetic materials, and products of vegetable origin, such as cereal meal, tree bark meal, wood meal and nutshell meal, cellulose powders and other solid carriers.

Suitable surfactants include the alkali metal salts, alkaline earth metal salts and ammonium salts of aromatic sulfonic acids, e.g. ligno-, phenol-, naphthalene- and dibutylnaphthalene- sulfonic acid, and of fatty acids, of alkyl- and alkylarylsulfonates, of alkyl sulfates, lauryl ether sulfates and fatty alcohol sulfates, and salts of sulfated hexa-, hepta- and octa- decanols and of fatty alcohol glycol ethers, condensates of sulfonated naphthalene and its derivatives with formaldehyde, condensates of naphthalene or of the naphthalenesulfonic acids with phenol and formaldehyde, polyoxyethylene octylphenol ether, ethoxylated iso- octyl-, octyl- or nonylphenol, alkylphenyl polyglycol ethers, tributylphenyl polyglycol ether, alkylaryl polyether alcohols, isotridecyl alcohol, fatty alcohol/ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ether or polyoxypropylene alkyl ether, lauryl alcohol polyglycol ether acetate, sorbitol esters, lignosulfite waste liquors or methyl- cellulose.

Aqueous use forms can be prepared from emulsion concentrates, suspensions, pastes, wettable powders or water-dispersible granules by adding water. To prepare emulsions, pastes or oil dispersions, the active compound(s) as such or dissolved in an oil or solvent, can be homogenized in water by means of wetting agent, tackifier, dispersant or emulsifier. Alternatively, it is possible to prepare concentrates consisting of active compound(s), wetting agent, tackifier, dispersant or emulsifier and, if desired, solvent or oil, and these concentrates are suitable for dilution with water.

Powders, materials for spreading and dusts can be prepared by mixing or concomitant grinding of the active compounds with a solid carrier.

Granules, e.g. granules coated by active compound(s), granules impregnated by active compound(s) and granules wherein the active compound(s) are homogenously distributed, can be prepared by binding the active compound(s) to solid carriers. Solid carriers are mineral earths such as silicas, silica gels, silicates, talc, kaolin, limestone, lime, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate, magnesium sulfate, magnesium oxide, ground synthetic materials, products of vegetable origin such as cereal meal, tree bark meal, wood meal and nutshell meal, cellulose powders, or other solid carriers.

The binding can be achieved e.g. by means of immersion, spraying or extrusion.

The concentrations of the active ingredient(s) in the ready-to-use preparations can be varied within wide ranges. In general, the formulations comprise from 0.001 to 98% by weight, preferably 0.01 to 95% by weight, of active ingredient(s). The active ingredient(s) are preferably employed in a purity of from 90% to 100%, preferably 95% to 100% (according to NMR spectrum).

The VLCFA-inhibitors (I) and, optionally, one or more compounds (II) are preferably employed in the form of a herbicidal composition, comprising an active ingredient and a solid or liquid carrier, where the active ingredient consists of VLCFA-inhibitors (I), in particular dimenthenamid or dimethenamid-P and one or more, preferably one or two, more preferred one, compound(s) (II), selected from the compounds of groups 11-1 to 11-16.

Accordingly, in a preferred embodiment of the invention, there is provided a method for controlling aquatic weeds, which comprises applying an effective amount of a herbicidal composition, comprising an active ingredient and a solid or liquid carrier, where the active ingredient consists of a VLCFA-inhibitor or of a VLCFA-inhibitor and one or more compounds (II) selected from the compounds of groups 11-1 to 11-16, to aquatic weeds and/or their aqueous habitat containing seeds or other propagating organs of said aquatic weeds.

Further provided is the use of the said herbicidal composition for controlling aquatic weeds.

The preparations can, for example, be formulated as follows:

I 20 parts by weight of the active ingredient(s) in question are dissolved in a composition composed of 80 parts by weight of alkylated benzene, 10 parts by weight of the adduct of 8 to 10 mol of ethylene oxide to 1 mol of oleic acid N-monoethanolamide, 5 parts by weight of calcium dodecylbenzenesulfonate and 5 parts by weight of the adduct of 40 mol of ethylene oxide to 1 mol of castor oil. Pouring the solution into 100 000 parts by weight of water and finely distributing it therein gives an aqueous dispersion which comprises 0.02% by weight of the active ingredient(s).

II 20 parts by weight of the active ingredient(s) in question are dissolved in a composition composed of 40 parts by weight of cyclohexanone, 30 parts by weight of isobutanol, 20 parts by weight of the adduct of 7 mol of ethylene oxide to 1 mol of isooctyl- phenol and 10 parts by weight of the adduct of 40 mol of ethylene oxide to 1 mol of castor oil. Pouring the solution into 100 000 parts by weight of water and finely distributing it therein gives an aqueous dispersion which comprises 0.02% by weight of the active ingredient(s).

III 20 parts by weight of the active ingredient(s) in question are dissolved in a composition composed of 25 parts by weight of cyclohexanone, 65 parts by weight of a mineral oil fraction of boiling point 210 to 280⁰C and 10 parts by weight of the adduct of 40 mol of ethylene oxide to 1 mol of castor oil. Pouring the solution into 100 000 parts by weight of water and finely distributing it therein gives an aqueous dispersion which comprises 0.02% by weight of the active ingredient(s).

IV 20 parts by weight of the active ingredient(s) in question are mixed thoroughly with 3 parts by weight of sodium diisobutylnaphthalenesulfonate, 17 parts by weight of the sodium salt of a lignosulfonic acid from sulfite waste liquor and 60 parts by weight of pulverulent silica gel, and the composition is ground in a hammer mill. Finely distributing the composition in 20 000 parts by weight of water gives a spray composition which comprises 0.1 % by weight of the active ingredient(s).

V 3 parts by weight of the active ingredient(s) in question are mixed with 97 parts by weight of finely divided kaolin. This gives a dust which comprises 3% by weight of the active ingredient(s).

VI 20 parts by weight of the active ingredient(s) in question are mixed intimately with

2 parts by weight of calcium dodecylbenzenesulfonate, 8 parts by weight of fatty alcohol polyglycol ether, 2 parts by weight of the sodium salt of a phenol-urea-formaldehyde condensate and 68 parts by weight of a paraffinic mineral oil. This gives a stable oily dispersion.

VII 1 part by weight of the active ingredient(s) in question is dissolved in a composition composed of 70 parts by weight of cyclohexanone, 20 parts by weight of ethoxylated isooctylphenol and 10 parts by weight of ethoxylated castor oil. This gives a stable emulsion concentrate.

VIII 1 part by weight of the active ingredient(s) in question is dissolved in a composition composed of 80 parts by weight of cyclohexanone and 20 parts by weight of nonionic emulsifier based on ethoxylated castor oil (Wettol® EM 31 , BASF SE). This gives a stable emulsion concentrate.

The VLCFA-inhibitor and the compounds 11-1 to 11-16 and/or their respective agriculturally acceptable salt, ester or amide can be applied jointly or separately, simultaneously or successively, before, during or after appearance of the aquatic weeds.

The required application rate of VLCFA-inhibitor, optionally in combination with compound^) Il and/or their respective agriculturally acceptable salt, ester or amide without formulation auxiliary, depends on the density of the aquatic weeds, on the development stage of the plants, on the water-movement, on the climatic conditions of the location where the composition is used and on the application method. In general, the application rate, more specifically the concentration in the aqueous habitat, is from 1 to 5000 ppb (parts per billion), preferably from 10 to 1000 ppb and in particular from 25 to 100 ppb of active compound(s).

In another preferred embodiment of the invention, the application rate is from 0.01 12 kg/ha to 1 1.2 kg/ha, preferentially from 0.0112 kg/ha to 1.12 kg/ha. The preparations are applied to the water body as either a surface or subsurface application. Application can be carried out by customary spraying techniques using, for example, water as carrier and spray liquid rates of from about 50 to 1000 I/ha (for example from 300 to 400 I/ha). Application of the preparations by the low-volume and the ultra-low- volume method is possible. In both methods small droplets with a high solids content are formed and dispensed by means of a highly pressurized gas stream. Also possible is the application of the preparations in the form of granules or microgranules. Also possible is the application of the preparations in the form of granules or extruded granules that can be applied to the water body surface, preferably by means of helicopter or watercraft such as airboats with the use of a spreader or blower to get even distribution. With granule formulations, the active ingredient is impregnated on inert carriers. The formulated granule can then be dispersed into the water column. Depending on the specific density and make up of the granule, the active ingredient can be released from the carrier as gravity propels it through the specific depth of the water column to the actual sediment hydrosoil of the water body. Delivery to the hydrosoil can allow for root uptake of the herbicide by sensitive aquaϋc weed species.

When applying a VLCFA-inhibitor by the method according to this invention the aquatic weeds in general are controlled slowly, meaning the biomass of the aquatic weeds in aqueous systems, for example ponds, lakes, creeks, rivers or swamps is declining slowly and gradually. This is a big advantage compared to other herbicides for control of the aquatic weeds - for example the herbicide endothall - which is also used in controlling the aquatic weeds and which exhibits very rapid, contact control of the aquatic weeds. Rapid, contact biomass reduction under high infestation levels is in general undesirable in that it for example can lead to rapid oxygen depletion in the aqueous system, which then may lead for example to significant fish mortality.

For a more clear understanding of the invention, specific examples are set forth below. These examples are merely illustrations and are not to be understood as limiting the scope and underlying principles of the invention in anyway. Various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the following examples and foregoing description. Such modifications are also intended to fall within the scope of the appended claims.

Example:

A Greenhouse test was initiated to evaluate the effects of dimethenamid-P for the control of aquatic weeds, exemplary for the control of Hydrilla verticillata. Materials and Methods: To begin the experiment, containers were filled and maintained with a volume of 4000 ml of distilled water at room temperature (24°C). To each container, an established hydrilla plant (potted in sand mixture) was transferred into the water column. Hydrilla plants were selected for uniformity and length of shoot growth (approx 15 cm). Plants were allowed to equilibrate in the columns for 24 hrs prior to herbicide treatment. Experimental treatments included an untreated control and dimethenamid at 500 ppb. Treatments were applied to water columns by the use of a pipette. Amount of herbicide applied was based on the total volume of the containers (4000 ml). After initial herbicide treatment, the water columns were gently stirred to ensure uniform distribution. Treatments were arranged as a complete random design with 3 replications. Each container was considered the experimental unit. Greenhouse conditions were maintained at 24/18°C (day/night) cycle for the duration of the experiment. Natural day length was supplemented with halogen lighting to provide a 14 hr photoperiod. Water level in the containers was periodically checked and maintained at the 4000 ml level for the duration of the study. At the end of eleven weeks, hydrilla shoot length and fresh weights were recorded.

Dimethenamid-P (EC) 720 g/l (Outlook® commercial formulation) was used in the test.

Results: Over the course of the study, dimethenamid-P was causing stunting and dieback of hydrilla tissue vs. the untreated control. At the end of the study, exposure to dimethenamid-P had caused significant reductions in both shoot length and biomass as determined by Students t-Test data analysis.

The results are presented in Table 1 :

Table 1 : Response of Hydrilla verticillata to static exposure of dimethenamid-P herbicide at 1 1 weeks after treatment (WAT).

Treatment Rate Shoot Length Fresh Weight

(PPb) (cm) (grams)

Control 37 17 dimethenamid-P 500 15 1 ,3 P= 0,02 0,001

Claims

1. A method for controlling aquatic weeds, which comprises applying a herbicidally effective amount of a VLCFA (very-long-chain fatty acid) biosynthesis inhibiting compound to the water body of aquatic weeds and/or their aqueous habitat containing seeds or other propagating organs of said aquatic weeds.

2. The method according to claim 1 , wherein the VLCFA-inhibitor is a chloroacetamide.

3. The method according to claim 2, wherein the VLCFA-inhibitor compound is dimethenamid or dimethenamid-P.

4. The method according to any of claims 1 to 3, wherein the application rate of a VLCFA- inhibitor is from 0.0112 kg/ha to 11.2 kg/ha.

5. The method according to any of claims 1 to 4, wherein the concentration of a VLCFA- inhibitor in the aqueous habitat is from 1 ppb to 5000 ppb.

6. The method according to any of claims 1 to 5, wherein aquatic weeds are selected from the group of submersed aquatic weeds.

7. The method according to any of claims 1 to 6, wherein aquatic weeds are selected from the genus of hydrilla.

8. The method according to claim 7, wherein the aquatic weed is hydrilla vertiicillata.

9. The method according to any of claims 1 to 8, wherein aquatic weeds are tolerant and/or resistant to the herbicide fluridone.

10. The method according to any of claims 1 to 9, wherein a herbicidally effective amount of a VLCFA-inhibitor is used in combination with at least one other herbicide.

11. The method according to claim 10, wherein a herbicidally effective amount of a VLCFA-inhibitor is used in combination with one or more other herbicide(s) Il selected from the following classes 11-1 to 11-16:

11-1 acetyl-CoA carboxylase inhibitors (ACC); • II-2 acetolactate synthase inhibitors (ALS), selected from imidazolinones, selected from imazapyr, imazaquin, imazamethabenz- methyl (imazame), imazapic, imazethapyr and imazamethapyr; pyπmidyl ethers; triazolopyrimidines; sulfonylureas; sulfonylaminocarbonyltriazoiinones and sulfonanilides; II-3 amides, selected from allidochlor (CDAA), benzoylprop-ethyl, bromobutide, chlorthiamid, diphenamid, etobenzanid (benzchlomet), fluthiamide, fosamin or monalide;

II— 4 auxin herbicides; II-5 auxin transport inhibitors; II-6 carotenoid biosynthesis inhibitors;

II-7 enolpyruvylshikimate-3-phosphate synthase inhibitors (EPSPS); II-8 glutamine synthetase inhibitors; ii-9 lipid biosynthesis inhibitors, selected from thiocarbamates, such as butylate, cycloate, di-allate, dimepiperate, EPTC, esprocarb, molinate, orbencarb, pebulate, prosulfocarb, thiobencarb (benthiocarb), thiocarbazil, tri-allate or vernolate; or isoxazolines, such as pyroxasulfon (KIH-485) benfuresate, ethofumesate, cafenstrole or perfluidone; 11-10 mitosis inhibitors; 1-11 protoporphyrinogen IX oxidase inhibitors, selected from diphenyl ethers, selected from bifenox, chlornitrofen (CNP), ethoxyfen, fluorodifen, fomesafen, furyloxyfen, nitrofen, nitrofluorfen or oxyfluorfeπ; • oxadiazoles, such as oxadiargyl or oxadiazon; cyclic imides, such as azafenidin, butafenacil, carfentrazone-ethyl, cinidon-ethyl, flumiclorac-pentyl, flumioxazin, flumipropyn, flupropacil, fluthiacet-methyl, sulfentrazone or thidiazimin; or pyrazoles, such as pyraflufen-ethyl (ET-751), fluazolate (JV 485) or nipyraclofen; pyridazinones, such as flufenpyr-ethyl; or triazolones, such as benzcarbazon; 1-12 photosynthesis inhibitors; 1-13 synergists; 1-14 growth substances; selected from aryloxyalcanoic acides and benzoic acids;1-15 cell wall synthesis inhibitors; 1-16 various other herbicides, selected from dichloropropionic acids, • phenylacetic acids, and aztprotryiπ, barban, bensulide, benzthiazuron, benzofluor, bumiπafos, buthidazole, butoron, chlorbufam, chlorfenprop-methyl, chloroxuron, cinmethylin, cumyluron, cycluron, cyprazine, cyprazole, dibenzyluron, dipropetryn, dymron, eglinazin-ethyl, eπdothall, ethiozin, fluorbentraπil, isocarbamid, isopropalin, karbutilatβ, mefluidide, monuron, napropamide, napropanilide, nitralin, oxaciclomefone, phenisopham, piperophos, procyazine, profluralin, pyributicarb, secbumeton, sulfallate (CDEC), terbucarb, triaziflam, triazofenamid and trimeturon.

12. The^'use of a VLCFA-inhibitor for controlling aquatic weeds.

=13. A method for controlling aquatic weeds, which comprises applying an effective amount of a herbicidal composition, comprising an active ingredient and a solid or liquid carrier, where the active ingredient consists of a VLCFA-inhibitor or of a VLCFA-inhibitor and one or more compounds (II) selected from the compounds of groups 11-1 to IM 6, according to claim 11 to the water body of aquatic weeds and/or their aqueous habitat containing seeds or other propagating organs of said aquatic weeds.

14. A composition suitable for controlling aquatic weeds consisting of a VLCFA- inhibitor being dimethenamid-p and one other herbicide Il selected from the classes 11-1 to 11-16 according to claim 11.