WO2000078142A2

WO2000078142A2 - Method for improving the resistance of cultivated plants to chemical stress

Info

Publication number: WO2000078142A2
Application number: PCT/EP2000/005250
Authority: WO
Inventors: Wilhelm Rademacher; Steven J. Bowe; Karl- Otto Westphalen
Original assignee: Basf Aktiengesellschaft
Priority date: 1999-06-17
Filing date: 2000-06-07
Publication date: 2000-12-28
Also published as: WO2000078142A3; AU5220200A

Abstract

The invention relates to a method for increasing the resistance of cultivated plants to chemical stress, triggered by insufficiently selective herbicides, or incorrect use of herbicides. The method is characterised in that the cultivated plant is treated with prohexadione or the salts thereof, in particular, calcium salt (I), which are suitable for use in agriculture.

Description

Process for increasing the resistance of crops to chemical stress

description

The present invention relates to a process for increasing the resistance of crop plants to chemical stress, triggered in particular by insufficiently selective or improperly applied herbicides, characterized in that the crop plant contains prohexadione or its agriculturally useful salts, especially the calcium salt (I),

or trinexapac-ethyl (II)

or with Acibenzolar-S-methyl ( ^: Benzothiadiazole) (III)

or with probenazole (IV)

is treated.

In the process according to the invention, the resistance of the plant to the herbicidal active substances glyphosate, glufosinate ammonium, herbicidal active compounds of the formula V, cyclohexenones such as setoxydim, cycloxydim, tepraloxydim or clefoxydim and bromoxynil is increased. Another object of the invention is the use of prohexadione, trinexapac-ethyl, acibenzolar-S-methyl (= benzothiadiazole) and / or probenazole and their agriculturally usable salts for increasing the resistance of crop plants to chemical stress, triggered in particular by insufficiently selective or improperly applied herbicides.

The productivity of crops can be reduced in many ways by stress factors. These include: viral diseases, bacterial and fungal pathogens, damaging insects, nematodes, snails, bite, heat, coolness, cold, lack of water, excessive water content in the soil, salinity, excessive radiation intensity, competition for light, water and nutrients due to accompanying flora, too high ozone in the air surrounding the plants, harmful emissions, e.g. from industrial plants or motor vehicles, improper or inapplicable herbicide applications, especially in fruit and wine crops, treatments with herbicides, insecticides, fungicides, bioregulators or foliar fertilizers with insufficient selectivity, foliar applications of crop protection agents or fertilizers during intensive sun exposure.

Most of the stressors mentioned can generally be summarized as "chemical stress". Countermeasures are only available to a limited extent here. The use of antidots to minimize herbicide-related damage to crops is particularly worth mentioning here. However, the use of antidotes is limited to certain herbicidal classes of active ingredients and is only important for Gramineae. Antidots for total herbicides such as glyphosate or glufosinate-ammonium are not available in practice because their use does not lead to satisfactory results.

A novel method for improving plant productivity is to trigger the natural defense reactions of a plant against fungal stressors before the onset of a fungal infection by means of suitable exogenous signals, in order to minimize the effects of the stress. The following agents are known, for example: "Bion" (active ingredient: acibenzolar-S-methyl) for inducing resistance to mildew (Erysiphe grxaminis) in cereals, and "Oryzemate" (active ingredient: probenazole) for inducing the Resistance to Pyri cularia oryzae in Reis, Annu. Rev. Phytopath.

35: 349-72 (1997).

The acylcyclohexadiones prohexadione-Ca and trinexapac-ethyl are known to have an action against fire blight.

Fire blight is triggered by the Erwinia amylovora bacterium and causes damage especially to pears, apples and quince.

In some places it is mentioned in general that acylcyclohexadiones such as prohexadione-Ca or trinexapac-ethyl protect crops against biotic and abiotic stressors [e.g. EP 0 123 001 AI, page 27, lines 20 and 21 (for prohexadione and related substances) or for trinexapac-ethyl and related compounds in EP 0 126 713]. However, specific examples are not given.

Prohexadione-Ca and Trinexapac-ethyl and other structurally similar acylcyclohexadiones are known as growth retardants, a certain group of bioregulators. The compounds mentioned prevent the biosynthesis of gibberellins. Certain gibberellins cause, among other things, a stretching of the plant cells and thus have a considerable influence on the plant growth. Treatment with prohexadione-Ca or trinexapac-ethyl accordingly leads to more compact plants, which can be of practical importance (e.g. reduction in the tendency to store grain, lengthening the mowing interval in lawn grasses).

Other types of growth retardants have been variously tested for their ability to induce resistance to biotic or abiotic stress in crop plants. It is known that triazolyls, such as paclobutrazole and unicoazole, have a certain fungicidal action owing to their structural proximity to certain fungicides [cf. Radema- rather, 1991, pp. 169-200, in: Plant Biochemical Regulators, HW Gausman (ed.), Marcel Dekker, Inc., New York]. Accordingly, there is no induced resistance to fungal attack. Work by A. Gilley and RA Fletcher [Journal of Plant Physiology 153: 200-207 (1998)] prove that paclobutrazole can make wheat germs resistant to the herbicide paraquat to a certain extent. However, it is not apparent from the relevant literature that a more compact growth caused by growth retardants generally leads to increased resistance to chemical stress. The object of the present invention was accordingly to develop a simple method by means of which the resistance of crop plants to chemical stressors, in particular to herbicides, is improved to a greater extent.

Surprisingly, it has now been found that probenazole, acibenzolar-S-methyl, prohexadione-Ca and trinexapac-ethyl induce resistance to chemical stressors, especially herbicides.

When the plants were treated with probenazole, acibenzolar-5-methyl, prohexadione-Ca and trihexapac-ethyl, increased resistance to chemical stress, triggered in particular by insufficiently selective or improperly applied herbicides, was observed. This effect was observed above all when applying the herbicides glyphosate, glufosinate ammonium, compounds of the formula (V), cyclohexenone herbicides such as Sethoxydim, Cycloxydi, Tepraloxydim or Clefoxydim and with bromoxynil.

Furthermore, the resistance to the herbicidal active ingredient of the formula V is increased, in compounds of the formula V and their agriculturally useful salts

the variables have the following meanings:

R ¹ , R ^{2 are} hydrogen, nitro, halogen, cyano, C ₁ -C ₆ -alkyl,

-C-C ₆ haloalkyl, Ci -Cβ -alkoxy, Cχ-C ₆ -haloalkoxy, Cx-C _δ -alkylthio, Ci -C ₆ -haloalkylthio, Cι-C ₆ -alkyl-sulfinyl, Ci - -haloalkylsulfinyl, Cι- C ₆ alkyl sulfonyl or _Cι-C6 haloalkylsulfonyl;

R ^{3 is} hydrogen, halogen or Ci-Cg-alkyl;

R ⁴ , R ^{5 are} hydrogen, halogen, cyano, nitro, Cχ-C alkyl,

Ci-C -alkoxy-Cχ-C ₄ -alkyl, di- (C ₁ -C ₄ -alkoxy) -Cι-C ₄ -alkyl, di- (Cι-C -alkyl) -amino-Cι-C ₄ -alkyl , [2,2-Di- (C ₁ -C ₄ alkyl) hydrazino-1] -C ₃ -C ₄ alkyl, Cj-Ce alkyliminooxy-C1-C ₄ alkyl, C ₁ -C ₄ -Alkoxycarbonyl -CC ₄ -alkyl, C ₁ -C ₄ -alkylthio-C ₁ -C -alkyl, C ₁ -C -haloalkyl,

C ₁ -C ₄ cyanoalkyl, C ₃ -C ₈ cycloalkyl, C ₁ -C ₄ alkoxy, ^c i "C ₄ alkoxy-C ₂ -C ₄ alkoxy, C _x -C ₄ haloalkoxy, hydroxy, C ₁ -C ₄ alkylcarbonyloxy, C ₁ -C ₄ alkylthio, C ₁ -C ₄ haloalkylthio, di - (C ₁ -C ₄ alkyl) amino, COR ⁶ , phenyl or

Benzyl, where the latter two substituents can be partially or completely halogenated and / or can carry one to three of the following groups:

Nitro, cyano, C ₁ -C ₄ -alkyl, C ₄ haloalkyl,

C ₁ -C ₄ alkoxy or C ₁ -C ₄ haloalkoxy;

or

R ⁴ and R ⁵ together form a C ₂ -C ₆ alkanediyl chain which can be substituted one to four times by C ₁ -C ₄ alkyl and / or substituted by oxygen or an optionally C ₁ -C ₄ alkyl Nitrogen may be interrupted;

or

R ⁴ and R ⁵ together with the associated carbon form a carbonyl or a thiocarbonyl group;

R ^{6 is} hydrogen, C ₁ -C ₄ -alkyl, Cχ-C -haloalkyl, ₁ -C -alkoxy, Cι-C ₄ -alkoxy-C ₂ -C ₄ -alkoxy, Ci -C ₄ -haloalkoxy, C ₃ -C alkenyloxy, C ₃ -C ₆ alkynyloxy or NR ⁷ R ⁸ ;

R ^{7 is} hydrogen or C ₁ -C ₄ alkyl;

R ⁸ Ci -C ₄ alkyl;

X 0, S, NR ⁹ , CO or CR ¹⁰ R ^{1: L} ;

YO, S, NR ¹² , CO or CR ¹³ R ¹⁴ ;

R ⁹ , R ^{12 are} hydrogen or C _x -C ₄ alkyl;

R ¹⁰ , R ¹¹ , R ¹³ , R ^{14 are} hydrogen, C ₁ -C ₄ alkyl, C ₁ -C ₄ haloalkyl,

C ₁ -C ₄ alkoxycarbonyl, -C-C ₄ haloalkoxycarbonyl or

C0NR ⁷ R ⁸ ;

or

R ⁴ and R ⁹ or R ⁴ and R ¹⁰ or R ⁵ and R ¹² or R ⁵ and R ¹³ together form a C -C ₆ alkanediyl chain which can be substituted one to four times by C ₁ -C ₄ alkyl can and / or by oxygen or an optionally C ₁ -C 4 alkyl substituted nitrogen may be interrupted;

R ^{15 is} a pyrazole of the formula VI linked in the 4 position

_R 16

in which

R ¹⁶ Ci -C ₆ alkyl;

ZH or S0 ₂ R ¹⁷ ;

R ^{17 is} C ₁ -C ₄ alkyl, C ₁ -C ₄ haloalkyl, phenyl or phenyl which is partially or completely halogenated and / or one to three of the following groups:

Nitro, cyano, C ₁ -C ₄ alkyl, C ₁ -C ₄ haloalkyl, C ₁ -C ₄ alkoxy or Ci -C ₄ haloalkoxy;

R ^{18 is} hydrogen or -CC ₆ alkyl

where X and Y do not simultaneously represent oxygen or sulfur.

The following list of compounds with herbicidal activity shows possible active compounds in which a higher resistance to the herbicides in question can also be observed when the plants are treated with probenazole, acibenzolar -5-methyl, prohexadione-Ca and trihexapac-ethyl. However, the list is not limited to these active substances.

bl 1, 3, 4-thiadiazoles: buthidazole, cyprazole

b2 amides: allidochlor (CDAA), benzoylprop-ethyl, bromobutide, chlorothiamide, dimepiperate, dimethenamid, diphenamid, etobenzanid (benzchlomet), flamprop-methyl, fosamin, isoxaben, monalide, naptalame, pronamid (propyzamid), propanil b3 aminophosphoric acids: bilanafos, (bialaphos), buminafos, gluf osinate-ammonium, glyphosate, sulfosate

b4 aminotriazoles: amitrole

b5 anilides: anilofos, mefenacet

b6 aryloxyalkanoic acids:

2,4-D, 2,4-DB, clomeprop, dichlorprop, dichlorprop-P, dichloroprop-P (2,4-DP-P), fenoprop (2,4,5-TP), fluoroxypyr, MCPA, MCPB, mecoprop, mecoprop-P, napropamide, napropanilide, tri-clopyr

b7 benzoic acids: chloramben, dicamba

b8 benzothiadiazinones: bentazone

b9 Bleacher: clomazone (dimethazone), diflufenican, fluorochloridone, flupoxam, fluridone, pyrazolate, sulcotrione (chloromesulone)

blO carbamates: asulam, barban, butylate, carbetamide, chlorobufam, chloropropam, cycloate, desmedipham, dialallate, EPTC, esprocarb, molinate, orbencarb, pebulate, phenisopham, phenmedipham, propam, prosulfocarb, pyributicarb, sulfallate (CDEC ), terbu-carb, thiobencarb (benthiocarb), tiocarbazil, triallate, vernolate

bll quinolinic acids: quinclorac, quinmerac

bl2 chloroacetanilides: acetochlor, alachlor, butachlor, butenachlor, diethatyl ethyl, dimethachlor, metazachlor, metolachlor, pretilachlor, propachlor, prynachlor, terbuchlor, thenylchlor, xylachlor

bl3 cyclohexenones: alloxydim, caloxydim, clethodim, cloproxydim, cycloxydim, sethoxydim, tralkoxydim, 2- {1- [2- (4-chlorophenoxy) propyloxyi - mino] butyl} '3-hydroxy-5- (2H-tetrahydrothiopyran-3-yl) -

2-cyclohexen-l-one

bl4 dichloropropionic acids: dalapon

bl5 dihydrobenzofurans: ethofumesate

bl6 dihydrofuran-3-one: flurtamone

bl7 Dinitroaniline: benefin, butralin, dinitramine, ethalfluralin, f luchloralin, isopropalin, nitralin, oryzalin, pendimethalin, prodiamine, profluralin, trifluralin

bl8 dinitrophenols: bromofenoxim, dinoseb, dinoseb-acetate, dinoterb, DNOC

bl9 Diphenyl ether: acifluorfen-sodium, aclonifen, bifenox, chloronitrofen (CNP), difenoxuron, ethoxyfen, fluorodifen, fluoroglycofen-ethyl, fomesafen, furyloxyfen, lactofen, nitrofen, nitrofluorfen, oxyfluorfen

b20 Dipyridylenes: cyperquat, difenzoquat-methylsulfate, diquat, paraquat dichloride

b21 ureas: benzthiazuron, buturon, chlorbromuron, chloroxuron, chlorto- luron, cumyluron, dibenzyluron, cycluron, dimefuron, diuron, dymron, ethidimuron, fenuron, fluormeturon, isoproturon, isouron, karbutilate, linuron, methabenzthiazuron, metobenzu- ron, metoxuron, monolinuron , monuron, neburon, siduron, tebutiuron, trimeturon

b22 imidazole: isocarbamide

b23 Imidazolinones: imazamethapyr, imazapyr, imazaquin, imazethabenz-methyl (imazame), imazethapyr b24 oxadiazoles: methazole, oxadiargyl, oxadiazon

b25 Oxirane: tridiphane

b26 phenols: bromoxynil, ioxynil

b27 phenoxyphenoxypropionic acid ester: clodinafop, cyhalofop-butyl, diclofop-methyl, fenoxaprop-ethyl, fenoxaprop-p-ethyl, fenthiapropethyl, fluazifop-butyl, fluazifop-p-butyl, haloxyfop-ethoxyethyl, haloxyfop-methyl, haloxyfopap-pif-methyl , propaquizafop, quizalofop-ethyl, quizalofop-p-ethyl, quizalofop-tefuryl

b28 phenylacetic acids: chlorfenac (fenac)

b29 phenylpropionic acids: chlorophenprop-methyl

b30 Protoporphyrinogen IX oxidase inhibitors: benzofenap, cinidon-ethyl, flu iclorac-pentyl, flumioxazin, flumipropyn, flupropacil, fluthiacet-methyl, pyrazoxyfen, sulfentrazone, thidiazimin

b31 pyrazole: nipyraclofen

b32 pyridazines: chloridazon, maleic hydrazide, norflurazon, pyridate

b33 pyridinecarboxylic acids: clopyralid, dithiopyr, picloram, thiazopyr

b34 pyrimidyl ethers: pyrithiobac acid, pyrithiobac sodium, KIH-2023, KIH-6127

b35 sulfonamides: flumetsulam, metosulam

b36 Sulfonylureas: amidosulfuron, azimsulfuron, bensulfuron-methyl, chlorimuron-ethyl, chlorosulfuron, cinosulfuron, cyclosulfamuron, ethamet- sulfuron methyl, ethoxysulfuron, flazasulfuron, halosulfuron-methyl, imazosulfuron-methyl, metsulfuron, metsulfuron misulfuron, prosulfuron, pyrazosulfuron-ethyl, rimsulfuron, sulfometuron-methyl, thifensulfuron-methyl, triasulfuron, tribenuron-methyl, triflusulfuron-methyl

b37 triazines: ametryn, atrazin, aziprotryn, cyanazine, cyprazine, des e-tryn, dimethamethryn, dipropetryn, eglinazin-ethyl, hexazinone, procyazine, prometon, prometryn, propazin, secbumeton, simazin, simetryn, terbumeton, terbutryn, terbutryn, terbutryn, terbutryn trietazin

b38 triazinones: et iozin, metamitron, metribuzin

b39 triazole carboxamides: triazofena id

b40 Uracile: bromacil, lenacil, terbacil

b41 Various: benazolin, benfuresate, bensulide, benzofluor, butamifos, cafenstrole, chlorothal dimethyl (DCPA), cinmethylin, dichlobe- nil, endothall, fluorobentranil, mefluidide, perfluidone, pipperophos

By treating the plants with probenazole, acibenzolar-S-methyl, prohexadione-Ca and trihexapac-ethyl, the flavoidoids eriodictyol, proanthocyanidins which are substituted on the C atom 3 with hydrogen, e.g. Luteoforol, luteoliflavan, aigeniflavan and tricetiflavan, as well as homogeneous and heterogeneous oligomers and polymers are increasingly formed from the mentioned and structurally related substances.

Increased concentrations of the phenols hydroxycinnamic acid (p-coumaric acid, ferulic acid, sinapic acid), salicylic acid or umbelliferone, including the homogeneous and heterogeneous oligomers and polymers formed from them, can be obtained after treatment of the plants with probenazole, acibenzolar-5-methyl, prohexadione- Ca and tri-hexapac-ethyl can be found on plants.

The process according to the invention can be used with good success in the following crop plants:

1. Gramineae, especially wheat, barley, rye, oats, corn, millet, rice or sugar cane 2. especially for rice, corn and sugar cane

3. for dicotyledons such as sugar beet, potato, rapeseed, sunflower, soybean, cotton, fruit crops such as apple and pear, and for grapevine.

Examples 1-4 from greenhouse experiments demonstrate the effect according to the invention of acibenzolar-S-methyl, probenazole and the acylcyclohexadione prohexadione-Ca and trinexapac-ethyl on the induction of resistance to chemical stress in crop plants. In tests on the antidote effect against herbicides, test plants were cultivated in plastic pots of approximately 300 ml volume on loamy sand with approximately 3% humus content and sufficient nutrient supply under greenhouse conditions. The resistance-inducing active ingredients were applied in different ways:

• In the case of seed treatment, the seeds of the crop plants to be protected are swollen or incrusted with thorough mixing with suitable aqueous or powdery preparations of the substance in question until a dry and seeding seed is available. If necessary, the distribution and adhesion of the active ingredient can be improved by adding so-called "stickers" (but also milk, beer, honey). In the cases described here, 100 ml of aqueous

Solution with the appropriate amount of resistance-inducing active ingredient used for 1 kg of seeds. With thorough mixing, the liquid intake was complete after about 3 hours under room conditions. After emergence, the plants pretreated in this way were sprayed at a shoot length of 12 to 18 cm (depending on the plant type) with aqueous preparations of various herbicidal active compounds.

• It is also possible to place granules with the resistance-inducing active substances near the seed during the sowing process.

• In spray applications, an aqueous preparation of the resistance-inducing compound is applied before, after or together with a herbicide. The application can be done on already established plants or after sowing on the surface of the not yet overgrown seedbed. In the present examples, the resistance-inducing compound was applied in aqueous preparation, in each case together with various herbicides, to young plants with a shoot length of 12 to 18 cm. In all cases, the degree of damage was determined visually approximately 20 days after herbicide treatment.

example 1

Anti-doping effect of probenazole, prohexadione-Ca and acibenzolar-S-methyl against glyphosate in rice (seed application)

Example 2.

Anti-doping effect of probenazole, prohexadione-Ca and aci benzolar-S-methyl against clefoxydim in rice (seed application)

0

5

Example 3

Anti-doping effect of probenazole and prohexadione-Ca against 0 glyphosate in rice (leaf application)

* Shoot length reduced

** ng = not rated because of atypical development

Example 4

Anti-doping effect of probenazole against compound A in rice (leaf application) while maintaining the selectivity for the grass weed Echinochloa crus-galli

Compound A

Claims

claims

Process for increasing the resistance of crop plants to chemical stress, triggered in particular by insufficiently selective or improperly applied herbicides, characterized in that the crop plant is treated with prohexadione or its agriculturally useful salts, in particular the calcium salt (I).

Process for increasing the resistance of crop plants to chemical stress, triggered in particular by insufficiently selective or improperly applied herbicides, characterized in that the crop plant is treated with trinexapacethyl (II).

Process for increasing the resistance of crop plants to chemical stress, triggered in particular by insufficiently selective or improperly applied herbicides, characterized in that the crop plant is treated with acibenzolar-S-methyl (= benzothiadiazole) (III).

4. A method for increasing the resistance of crop plants to chemical stress, triggered in particular by insufficiently selective or improperly applied herbicides, characterized in that the crop plant is treated with probenazole (IV).

15 5. The method according to claims 1 to 4, characterized in that the active ingredients are applied to crops as seed treatment in application rates of 0.1 to 10,000 mg / kg, preferably from 0.3 to 1,000 mg / kg.

6. The method according to claims 1 to 4, characterized in that the active ingredients for improving the resistance to herbicides on young plants are supplied before planting out in the field by watering or spray application.

25 7. The method according to claims 1 to 6, characterized in that the active ingredients to improve the resistance to herbicides are applied together with the herbicides in question as a spray or scatter application in the habitat of the plants.

30

8. The method according to claims 1 to 7, characterized in that the crops are Gramineae, in particular wheat, barley, rye, oats, corn, millet, or rice.

35

9. The method according to claims 1 to 7, characterized in that the crop plants are Gramineae, in particular rice, corn or sugar cane.

40 10. The method according to claims 1 to 7, characterized in that the crop plants are dicotyledons, in particular sugar beet, potato, rapeseed, sunflower, soybean, cotton, fruit crops such as apple and pear, and vines.

45

11. The method according to claims 1 to 10, characterized in that the resistance to the herbicidal active ingredient glyphosate is increased.

12. The method according to claims 1 to 10, characterized in that the resistance to the herbicidal active ingredient glucosinate-ammonium is increased.

13. The method according to claims 1 to 10, characterized in that the resistance to the herbicidal active ingredient of the formula V is increased, in compounds of the formula V and their agriculturally useful salts

R3 he variables have the following meanings:

R ¹ , R ^{2 are} hydrogen, nitro, halogen, cyano, C ₁ -C ₆ -alkyl,

C _J -C _Ö haloalkyl, Ci-C _δ alkoxy, Cx-Cβ-haloalkoxy, Cι-C ₆ alkylthio, Cχ-C ₆ haloalkylthio, Cι-C ₆ alkyl - sulfinyl, Ci -C ₆ haloalkylsulfinyl , -CC ₆ alkyl sulfonyl or Ci -C ₆ haloalkylsulfonyl;

R ^{3 is} hydrogen, halogen or Cj-Cg-alkyl;

R ⁴ , R ^{5 are} hydrogen, halogen, cyano, nitro, C ₁ -C ₄ alkyl, Cx -C ₄ alkoxy-C ₁ -C ₄ alkyl,

Di- (C ₁ -C ₄ -alkoxy) -C ₁ -C ₄ -alkyl, di- (-C-C ₄ -alkyl) -ami- no-Cι-C - alkyl, [2, 2 -Di- (C ₁ -C ₄ - alkyl) hydrazino-1] -C ₁ -C ₄ alkyl, -C-C ₆ alkyliminooxy-

Ci -C ₄ alkyl, C ₁ -C ₄ alkoxycarbonyl -CC-C ₄ alkyl, Ci -C -alkylthio -CC-C ₄ -alkyl, C ₁ -C ₄ -haloalkyl, -C-C-cyanoalkyl, C ₃ -C ₈ cycloalkyl, C ₁ -C ₄ alkoxy, C ₁ -C ₄ alkoxy-C -C alkoxy, -C -C haloalkoxy, hydroxy, C1-C4 alkylcarbonyloxy, C ₁ -C ₄ alkylthio ,

C ₃ -C ₄ haloalkylthio, di - (C ₁ -C ₄ alkyl) amino, COR ⁶ , phenyl or benzyl, where the latter two substituents can be partially or completely halogenated and / or one to three of the following Groups can wear: Nitro, cyano, _C1-C4 alkyl, Ci _-C4 haloalkyl,

C ₁ -C ₄ alkoxy or C ₁ -C ₄ haloalkoxy;

or

R ⁴ and R ⁵ together form a C -C ₆ alkanediyl chain which can be substituted one to four times by C ₁ -C alkyl and / or by oxygen or an optionally substituted C ₃ -C ₄ alkyl can be interrupted;

or

R ^{6 is} hydrogen, C ₁ -C ₄ -alkyl, C ₁ -C ₄ -haloalkyl, C ₁ -C ₄ -alkoxy, Ci -C -alkoxy-C -C ₄ - alkoxy, C ₁ -C ₄ -haloalkoxy, C ₃ -C ₆ alkenyloxy, C ₃ -C ₆ alkynyloxy or NR ⁷ R ⁸ ;

R ^{7 is} hydrogen or C ₁ -C ₄ alkyl;

R ^β C _I -C ₄ alkyl;

X 0, S, NR ⁹ , CO or CR ¹⁰ R ^{1; L} ;

Y 0, S, NR ¹² , CO or CR ¹³ R ¹⁴ ;

R ⁹ , R ^{12 are} hydrogen or Ci -C ₄ alkyl;

R ¹⁰ , R ¹¹ , R ¹³ , R ^{14 are} hydrogen, Cχ-0 ₄ -alkyl, Cι-C ₄ -haloalkyl, C ₁ -C ₄ -alkoxycarbonyl, C ₁ -C ₄ -haloalkoxycarbonyl or CONR ⁷ R ⁸ ;

or

R ⁴ and R ⁹ or R ⁴ and R ¹⁰ or R ⁵ and R ¹² or R ⁵ and R ¹³ together form a C -C _δ alkanediyl chain which can be substituted one to four times by C ₁ -C ₄ alkyl can and / or can be interrupted by oxygen or an optionally substituted C ₁ -C ₄ alkyl;

R ^{15 is} a pyrazole of the formula VI linked in the position

R16 Z

in which

10 R ¹⁶ Ci -C ₆ alkyl;

ZH or S0 ₂ R ¹⁷ ;

R ^{17 is} C ₁ -C ₄ alkyl, C ₁ -C ₄ haloalkyl, phenyl or phenyl which is partially or completely halogenated and / or carries one to three of the following groups:

Nitro, cyano, C ₁ -C ₄ alkyl, C ₁ -C ₄ haloalkyl, C ₁ -C ₄ alkoxy or C ₁ -C ₄ haloalkoxy;

20 R ^{18 is} hydrogen or -CC ₆ alkyl

where X and Y do not simultaneously represent oxygen or sulfur.

25 14. The method according to claims 1 to 10, characterized in that the resistance to cyclohexenone herbicides such as Sethoxydim, Cycloxydim, Tepraloxydim or Clefoxydim is increased.

15. The method according to claims 1 to 10, characterized in that the resistance to the herbicide bromoxynil is increased.

16. Use of prohexadione, trinexapac-ethyl, acibenzolar-35 S-methyl (= benzothiadiazole) and / or probenazole and their agriculturally usable salts for increasing the resistance of crop plants to chemical stress, triggered in particular by insufficiently selective or improperly applied herbicides. 0

5