GB2225943A - Herbicide and growth-regulating composition - Google Patents

Description

i HERBICIDE AND GROWTH-REGULATING COMPOSITION The invention relates to a

herbicide and growth-regulating composition. More particularly it relates to such a composition containing a) 3-isopropyl-1H-'4,'1,"-'Uenzo'thiadiazin-4(3H)-one- -2,2-dioxide and b) (+)-2-ethoxy-2,3-dihydro-3,3-dimethylbenzofuran- -5-yl methanesulfonate or any of its enantiomers.

These will preferably be in admixture with one or more solid and/or liquid carrier(s), preferably with the grist of native mineral or synthetic materials, or inert solvent(s), preferabl xylene or cyclohexanone and optionally with surface active agent (s), preferably anionic or nonionic emulsify ing or dispersing agent(s).

A As used the tern "r-pstJ-c-ide" means herbicidal Or deS-JCC2nt 2,d,/or defoliating ac tion.

Both active ingredients of the composition according to the invention are known:

- 3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one- -2,2-dioxide (hereinafter bentazon, C.A. Registry Number: 25057-89-0) and its preparation were described in the Belgian patent specification No. 702,877 whereas the herbicidal properties thereof were published by A. Fischer (Proc. Br. Weed Control Conf. 9th, 1968, 2, page 1042). (+)-2-Ethoxy-2,3-dihydro-3,3-dimethylbenzofuran-5-yl methanesulfonate and its enantiomers (herein- after ethofumasate, C.A. Registry Number: 26 225-79-6) and their preparation were described in the British patent specification No. 1,271, 659 whereas their herbicidal properties were published by R. K. Pfeiffer (Symp. New Herbic. 3rd, 1969, page 1). /The Pesticide Manual, 8th ed. (1987) under entry numbers of 770 and 5750, respectively-7

Several combinations of both above active ingredients with other active agents are also known: see The Pesticide Manual 8th ed. (1987) under entrv numbers of 500, 770, 4480, 7301, 7520, 7791, 7810, 7861 and 10-120 2S well as 1411, 2400, 3040, 5750, -7301 and in -160, res-iPectively; as well as Hungarian patent specification No. 192, 220.

The development of a postemergent weed control technology for maize was necessitated by the propagation of herbicide-resistant weeds and the spreading of particularly dangerous, herbicide-tolerant weed species also involving cultivated plants, e.g. sunflower of random sprouting character.

The first composition used for this purpose contained 2,4-D as active agent; however, during its use it transpired that it can be employed only during a state of development of the cultivated plant of 10 to 20 cm, otherwise the maize is damaged. Its effect is restricted to dicotyledonous weeds.

3 - Oicamb2, which can be sprayed in maize culture with a development state of 7 to 15 cm, has 2 similar effect. A further drawback of the compositions based on hormones (2,4-0, dicamba, MCPA, MCPB, MCPP, dichlorprop, mecoprop) is that dicotyledonous plants are extremely sensitive to them; thus, if they are blown or sprayed elsewhere, the adjacent growth can be threatened by permanent damage.

When bromfenox-im, bromoxynil or ioxynil are used, the loss caused by fall out is not a consideration, but these agents are inactive against several dicotyledonous weed species.

The oily atrazine composition is also Useful for treating 2 culture,bLIt csnnl-.t be 1" - -resistant weeds and a number employed on triazine of monocotyledonous weed species.

The selective use of paraquat, a total weed-killer of the bipyridine series, proved to be unfruitful since Safer compositions became known; the effect of paraquat is extremely short and is accompanied by well-known resistance problems.

Pyridate is useful for controlling dicotyledonous weeds, principally some amaranth species in maize cultures up to the 4 to 6-leaf development stage.

The utilization and synergism of an ethofumesate+chlorotriazine combination in maize culture 4 - for the chemical control of mono- and dicotyledonous weeds are described in the Hungarian patent specification No. 192,222.

Similarly, bentazon is useful for the control of dicotyledonous weeds in maize of 7 to 15 cm size. Its combinations with MPCA, MCPD, dichlorprop, mecoprop. isoproturon, atrazine and cyan2zine, which strengthen the dicotyledone-killing activity, are also known. The combination of bentazone withpropanil can be used only in rice cultures.

D N P B c o m b i n a t i o n s have the most prolonged ef fect knovn for postemergent weed control in pea cultures.

Their drawback is that they kill only 2 to 4-leaf dicotyledonous wecd--, are rather toxic and also may be harmful to cultivated plants above 25 0 C. MCPB can be applied exclusively against dicotyledonous weeds in pea cultures of 6 to 8 cm development state.

For combatting monocotyledonous weeds, the particular monocotyledonekilling compositions (alloxidin sodium, dichlofop-methyl, fluazifopbutyl) are used.

Bentazon may also be used in pea cultures at a 6-8 cm state of the stock against 4 to 6-leaf dicotyledonous weeds. Both its effect and the danger of phytotoxicity are accelerated and strengthened by warm weather whereas the development of its action is slowed down by cool weather.

From the herbicides mentioned above, diquat dibromide, closely related to paraquat, is the oldest known chemical agent for either defoliation or desiccation. A significant advantage of its use is the rapid desiccating effect on all green plant parts. Rapid action is essential so that the intervention can be carried out during the optimum period of maturation. Its drawback lies in a fairly dangerous toxicity to warm- blooded animals; it cannot be used under dry conditions in potato stocks because it induces skin-browning which leads to a deterioration in storing properties. A Chenopodium album be controlled (killed) by diquat of 10 cm size cannot since its waxed leaves do not take up the composition Kidir et al.: Weed Control and Chemical Crcp Re-gulaMez6gazdasigi Kiad6, Budapest well as: Z. Ocsk6 et al.: Plant Hungarian), tion (in Hungarian), 1983, page 519; as Protective Agents and Fertilizers (in Mez5gazd@sigi Kiadd, Budapest 1988, page 464/.

Metoxuron is a known herbicide for the chemical weed control of eared cereals; it is also useful for the desiccation or defoliation of fibre hemp, potato and rape. This active agent is less harmful to warm -blooded animals than is diquat; it does not discolour the potato seeds and can also be used under dry conditions.

Its disadvantage lies in the significantly lower effect in comparison to that of diquat; it does not kill monocotyledonous weeds and should preferably be used at 6 temperatures below 25 'C in order that the drying up of the spray solution is not too rapid in respect of being taken up by the plants /H.A. Roberts (Editor): Weed Control Handbook: Principle 7th, Blackwell Scientific 5 Publications, Oxford 1982, page 5337.

There therefore still remains a need for a post-emergent herbicide spray for maize and pea cultures by use of which these cultures are not damaged, both mono- and dicotyledonous weeds are killed, which in addition is not dangerous to adjacent growth by fall out or other transport and is not too expensive in comparison to both the cheap hormone-based compositions and atrazine.

We have now found during our investigations that, by combining bentazon with ethofumesate, preferably in a 10:1 to 0. 5:1 weight ratio, a combination is obtained, which has a synergistic effect; produces this synergistic effect at a significantl lower active ingredient content; exerts an extremely rapid (, ,knock down") action; and unexpectedly possesses both synergistic desiccant and defoliating effects.

Thus, the present invention relates to a herbicide and growth-regulating composition, which comprises 7 3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one-2,2-dioxide and (+)-2ethoxy-2,3-dihydro-3,3-dimethylbenzofuran-5-yl methanesulfonate or any enantiomer thereof Such a composition will desirably be prepared in admixture with one or more solid and/or liquid carrier(s), preferably with the grist of native mineral or synthetic materials, or inert solvent(s), preferably xylene or cyclohexanone and optionally surface active agent(s), preferably anionic or nonionic emulsifying or dispersing agent(s). the invention further relates to a method of controlling weeds or of desiccating and/or defoliating cultivated plants, particularly crops such as maize, soy, sunflower, potato, flax and hemp, which comprises treating the cultivated plants, preferably in their 1 to 6-foliage-leaf state, or up to 1 to 4 weeks before harvesting, with a solution of the composition according to the invention, desirably containing 0.1 to 12 % by weight of the active ingredient mixture. Treatment will preferably take place with 50 to 1000 litre/hectare (1/ha), preferably 50 to 300 1/ha, of solution, generally a spray solution.

The synergistic composition according to the invention is useful to control both mono- and dicotyledonous weeds and, due to its long-term action, it provides a protection against weeds during the whole time of growth (calculated from the treatment) of the cultivated plants.

8 - The ratio and dose of both active ingredients, i.e. bentazon and ethofumesate can be varied under relatively wide limits depending upon the conditions of use (e.g. extent of weed-cover species of the cultivated plant, development state of the cultivated plants and weeds, quality of the soil, weather conditions). Care has only to be taken that the threshold value of phytotoxicity should not be exceeded. (Maize as cultivated plant may, for example, be damaged by an amount of even 5 1/ha of a 20 EC formulation prepared from ethofumesate.) The weight ratio of bentazon to ethofumesate may be varied from 10:1 to 0.5:1 whereas their dose May be between 0.5 and 5 kg/hectare (kg/ha), preferably between 1 and 4 kg/ha. r1he bentazon/ethofumesate mixture will desirably comprise from 0.1 to 95% by weight of the composition.

By using the composition of the invention, the weed control is ca-rried out-in the postemergent phase. A preferred method for e.g. maize culture is to carry out the weed control in the period Of an I to 6-, preferably 2 to 5-leaf state of the maize.

Another factor to consider at the time of use is the development state of the weeds: the control of weeds, for example, is very efficient during their 2 to 6-leaf state.

The desiccation and/or defoliation by using the composition of the invention are accomplished 1 to 6 weeks before the expected harvest, depending on the species, variety and maturation state of the cultivated Plant, extent of the weed-cover and the weather conditions.

Essentially, the techniques of spraying are similer to those described for weed control, except that the amount of spray solution applied via an air-route frequently lower (50 to 60 1/ha).

is & According to the invention, a spray solution of 50 to 1000 1/ha, preferably 50 to 300 1/ha, is prepared from the amount defined above of the composition and sprayed out by using a medium or little drop size under a pressure of 2.5 to 3.5 bar. The active ingredient concentration of the spray solution amounts to 0.1 to 12, preferably 1 to 10 % by weight.

According to the present invention, the two active ingredients are formulated to compositions such =s wettable pcwders NP), emulsifiable ccnce-,trntp': (ES), suspensinn concentrates (SC) and other forms in 2 Manner known per se /Pesticide Formulations, Ed. Wade van V21kenburg, Marcel Dekker, Inc. New York, 1973).

In these compositions, the active ingredients are mixed with solid or liquid carriers, solvents, tensibes and optionally with other auxiliary materials (see, e.g. the British patent specification No. 1,552,277).

The solid carriers or fillers may be inorganic 25 or organic, natural or synthetic materials.

The solid carriers and fillers of natural origin May be obtained by grinding various minerals - (such as diatomaceous earth, bentonite, perlites, kaolinite, attapulgite or dolomite).

The synthetic solid carriers and fillers may be e.g. silicic acids with a large surface area (aerosils), silica gels prepared by various processes, or calcium carbonate. The solid carriers and fillers of organic origin, e.g. wood flour, are grists of various plant. wastes.

Suitable liquid carriers and solvents are e.g.: water; various organic solvents and their mixtures such as alcohols, e.g. ethanol, propanols, butanols or benzyl alcohol; glycols, e.g. ethyleneglycol, diethyleneglycol or propylene glycol; ketones, e.g. acetone, miethyl isobuty! ketone and cyclohexanone; Y esters of fatty 2C-'-H-- and other organic acids, e.g. ethyl or isobutyl acetate, methyl benzoate and diocty.L phthalate. Other polar organic solvents such as acid amides, e.g. dimethylformamide; lactones and lactams, e.g. isobutyrolactone or N-methylpyrrolidone; may also be chosen for the Same purpose. Dimethylsulfoxide is also 2 preferred solvent. Apolar hydrocarbons with -a boiling point between 150 and 270 0 C such as cyclo hexane; aromatic hydrocarbons,e.g. xylenes and alkyl benzenes, may also serve as useful solvents.

A wide range of surface active agents can be used: such substanc.es are e. g. emulsifying, dispersing anc wetting agents all of which are well known in the formulation of plant protective compositions.

11 - The surface active agents may be ionic or nonionic. The ionic are anionic, cationic or 2mphoteric in character.

Anionic surface active agents are e.g.: various organic acids, e.g. carboxyliC and sulfonic acids; alcohol sulfates and sulfonates; aralkyl phosphate esters and their salts formed with alkaline metals, alkaline earth metals, ammonium ions or organic amines, e.g. soft soaps, Calcium, sodium, isopropylammoniu..-n or triethanol2mmonium dodecylbenzenesulfonate; sodium, calcium or ammonium ligninsulfonate; as well as sodium diiscoctylsulfosuccin2te and sodium polyacrylate.

Nonionic surface active agents which may be used include e.g.: the ethers formed fran ethylene oxide with alcd-Dls; esters fonTed from ethylene oxide with fatty acids cr oleic acids; ethers of ethylene oxide with aralkylphenols; block polymerisates of ethylene oxide formed with propylene oxide as well as esters and ethers thereof and derivatives formed from ethylene oxide with fatty acids or oleic acids and hexitol anhydrides and the like Examples of such substances are e.g.

the nonylphenol polyglycol ethers or the polyoxyethylene esters of oleic acid.

Cationic surface active agents which may be used include e.g.: the halides or sulfates of higher alkylamines such as xetyl pyridinium chloride or stearyl dimethylammonium chloride.

Suitable amphoteric surface active agents are e.g. betains, lecithins or sodium N-methylalkyl-taurimide.

Adhesion-promoting agents such as native or synthetic polymers, e.g. starch, casein, carboxymethylcellulose, hydroxyethylcellulose, polyvinylpyrrolidone or polyacrylic acid may be employed as auxiliary materials.

Polyoxyethylene- and polypropylene-containing block polymerisates, higher alkanols or silicones are e.g. useful as anti- foam agents.

The invention is illustrated in detail by the following non-limiting Examples. In these Examples "% by wt." means per cent by weight and "a.i. " means active ingredient.

The test plants used in the ExampleS are listed hereinafter. Zea mays (ZEAMA) = maize TritiCUM 2estivum (TRIAE) = wheat Avena fatua (AVEFA) = wild oat Helianthus annuus (HELAN) = sunflower Pisum sativum (PISSA) pea Beta vulgaris (BEETVU) sugar beet Amaranthus retroflexus (AMARE) = pilous amaranth Solanum lycopersicum (SOLLY) = tomato Chenopodium album (CHEAL) Set2ria glauca (SETGL) Setaria verticillate (SETVE) Datura stramonium (DATST) Digitaria sanguinalis (DIGSA) Echinochloa crus-galli (ECHCR) 5 Hibiskus trionum (HIBTR) The herbicide and hypotoxic activities, respectively, were scored by using a scale from 0 to 3 as explained hereinafter.

Score of the herbicidal and Herbicidal or phytotoxic phytotoxic activity effect (%) 0 011 i 1 1/2 2 2/3 3 0 5 15 30 60 90 100 The synergistic effect of the compositions according to the invention were calculated by using the formula of S.R. Colby (Weeds Vol. 15, January 1967 No. 1, page 20).

14 Examples 1 to 6 Preparation of spray solutions Spray solutions (tank mixtures) are prepared from the commercially available aqueous solution of bentazon (480 g/litre of a.il) and ethofumesate 20 EC. For preparing spray solutions with 10:1 to 0.5:1 weight ratios, the following amounts of bentazon (480 g/litre of a.i.) and ethofumesate 20 EC have to be weighed in to obtain spray solutions with the concentra tions given in the following Table:

Example Weight WtA of a.i. Bentazon Ethofumesate No. ratio in the spray (480 g/litre) 20 EC of a.i. solution M1 M1 1 10:1 1.18 20.8 50 2 7.5:1 0.91 15.6 50 3 4.2:1 0.55 8.75 50 4 2.5:1 0.33 5.2 50 1.5:1 0.26 3.1 50 6 0.75:1 0.7 1.6 50 Example 7 Preparation of a wettable powder (WP) Bentazon Ethofumesate Silica gel with large surface area.

parts bv weight 80 8 6 Sodium salt of sulfite waste liquor Ethoxylated alkylphenol (50 % in a silica gel carrier with a great surface) 3 3 Bentazon Ethofumesate DiatOmaceous earth Silica gel with a great surface Oalcium salt of sulfite waste liquor Ethoxylated alkylphenol (50 % on a silica gel carrier with a great surface) Example 8

Preparation of a wettable powder (WP) parts by weight 5 10 50 5 6 4 The powder mixtures are crushed to a particle size below 40 / UM.

Bentazon Ethofumesate Xylene Example 9 Preparatiopn of an emulsifiable concentrate (EC) parts by weight 7. 5 12.5 42.5 Cyclohexanone Ethanol Calcium dodecylbenzenesulfonate (70 % solution in isobutanol) 5 Fatty alcohol polyglycol ether 20.0 7.5 5.0 5.0 100.0 The above composition is prepared by direct dissolution.

Example 10

Greenhouse tests (postemergent screening) These examinations were carried out in 4 repetitions on 10 test plant species in perforated 13 plastic bottles bedded in perlite of 6x6x8 cm. sJzc (see Table 1).

The seeds were sown according to their size and biologicaI properties 2 to 3 weeks before the treatment. Ten seeds each of weeds and 6 seeds each of cultivated plants were sown in a Plastic bottle. The cultivated plants were selected in the week before the treatment in order to provide 3 uniform plant stock. The test plants (both cultivated plants and weeds) were treated in their 2 or 3 week-old state, according to the amount of development.

The evaluation of efficacy of the compositions accordinc: toth- invention was carried out on the 2nd, 5th and 12th 17 - days following the treatment. The results are summarized in Tables 2, 3 and 4 and are also analysed later in the text.

Table 1

Treatment No.

Untreated control Bentazon Bentazon Bentazon Bentazcn Ethofumesate 3 4 5 6 7 Ethofumesate 8 Ethofumesate 9 Ethofumesate 10 Bentazon+ ethofumesate 11 Bentazon+ethofumesate 12 13 14 Bentazon+ethofumesate Untreated control Bentazon+ethofumesate Dose kg/ha of a. i.

2.5 1.25 1.0 0.75 1.0 0.5 0.5 0.3 2.5+1.0 1.25+0.5 1.0+0.4 0.75+0.3 Wt. ratio of a.i. in the succession order of bentazon +ethofumesate 2 5 1 2 5 1 2 5 1 2. 5: 1 Table 2

Herbicidal effect on-i:ne -Cest plants on:the 2nd day after treatment f-i'eatalcht Dose Wt. ratio of T e S t p 1 a r) t S No'. kg/ha of bentazon+etha- herb ' icidal,effect on a.l. fumesate ZEAMA TIRIAIR, AVEPA IMLAN PISSA BEWU AIMBE SOMY CIIISAL SETC-L 1 - - 0 0 0 0 0 0.0 0 0' 0 2 5 0 0 0 0 0 0 0 0 0 0 3 1925 0 0 0 0 0 0 0 0 0 0 4 1,0 0 0 0 0 0 0 0 0 0 0 0, 7 5 0 0 0 0 0 0 0 0 0 C.

- 0 0 0 0 0 0 0 0 0 0 0,5 - 0 0 0 0 0 0 0 0 0 0 8 OP4 - 0 0 0 0 0 0 0 0 0 0 9 013 - 0 0 0 0 0 0 0 0 0 0 10. 2, 5+1 % 0 2,5:1 1 011 1 3 1 3 3 3 3 2 11 1,25+0,3 2, 5:1 0 0 1 3 1 3 3 3 3 2 12 130+094 2,5:1 0 0 1 3 1 3 3 3 3 2 13 - - 0 0 0 0 0 0 0 0 0 0 14 0975-Ci 3 2,5:1 0 0 1 3 1 3 3 3 3 2 1 Table 3

Herbicidal effect on the test plants on the 5th day after Treatment Dose No. kg/ha of a. i.

Wt. ratio of bentazon+ethofumesate treatment T e s t p 1 a n t s nerbicidal ettect on ZEA1v1A TRI.kE' AWEPA ilis'IJ..I. 1 PIS3,2)A IIISEM MvLARE SOLLY CH-EAL SEM 1 - - 0 0 0 0 0 0 0 0 0 2 2,5.0 0 0 2 0 3 3 2 3 0 3 1,25 0 0 0 2 0 3 3 1 2 0 4 lo 0 0 0 2 0 3 3 1 2 0 0,75 0 0 0 1 0 2 2 1 1 0 6 130 0 1/2 1/2 1 1 1 1 1 1 1 7 0,5 0 1 1 0 0 0. 0 0 0.0 8 0,4 0 0 0 0 0 0 0 0 0 0 9 0,3 0 0 0 0 0 0 0 0 0 0 2,5+1)0 2,5:1 0/1 0/1 1/2 3 0/1 3 3 3 3 2 11 1,25+0,5 2,5.1 0 0 1 3 0 3 3 3 3 2 12 M+OP4 2)5:1 0 0 1 3 0 3 3 3 3 2 13 - 0 0 0 0 0 0 0 0 0 0 14 0,75+03 235:1 0 0 0 3 0 3 3 3 3 2 0 0 0 0 1 0 1.

0 0 0 0 1 0 0 0 0 3 4 6 7 8 9 11 12 13 14 0,75-1-0,3 0 0 1/2 2, 5:1 2 3 5:1 2, 5:1 2,5:1 0 1 0/1 0 0 0 0 0 0 0 0/1 0,11 0 0 0 0 0 3 3 3 0 3 0 1/2 1 1 0 0' 0 0/1 0 0 0 0 Table 4 es plantslon the 12th day after treatment Herbicidal effer+ nn Treatment Dose W t. ratio of T e s t p 1 a n t's No. kg/ha of bentazon+etho- herbicidal effect on fumesate ZEAPR TRIA1,3 AVEPA-HEIAUT PISiA DEM AILM, SOLLY C11EAL SEM 0 0 0 0 0 0 0. 0. 0 0 2 2 5 - 0 0 2/3 3 3 2/3 1,25 - 0 0 2 3 3 1/2 - 0 2 3 3 1 0,75 - 0 1/2 Ito 0 p 5 0,4 0 p 3 2,5+1O 1,25+0,5 190+0)4 2/3 0 0 0 0 2/3 1 1 1 0 0 0 0 0 3 3 3 0 3 3 2 2 0 0 0 3 3 3 0 3 3 2 0 3 3 3 0 0 0 0 0 1 0 0 0 2 2 2 0 - 21 It is obvious from the data of Table 2 that a herbicidal or phytotoxic effect was induced within 2 days of treatment with the combinations whereby the dicotyledonous weeds (AMARE, CHEAL) were killed and -of the monocotyledonous weeds SETGL was moderately damaged and the eared plants-related AVEFA suffered only slight damage.

A mild phytotoxic effect on the monocotyle- donous cultivated plants (ZEAMA, TRIAE) was observed only by using the highest-dose combination (treatment No. 10). From the dicotyledonous cultivated plants HELAN was completely destroyed by the combination - in the sense treatments, a -fact -heing signif,;c@nt - that the sunflower of random sprouting character was totally killed in the course of a crop rotation.

The dicotyledonous waxed-leaf pea (PISSA) was mildly damaged by the combinations at the beginning; however, it recovered from this damage after 5 days (see Table 3).

The similarly dicotyledonous BETVU and SOLLY were completely killed by the combinations. From the complete control of the latter cultivated plant it can be concluded that significant weed species belonging to the Solanum genus can be controlled in this manner.

In addition, it can be seen from Table 3 that the combinations exerted an extremely rapid (knock down) effect in respect of the evalution carried out on the 5th day. Furthermore an intense synergism could be noted on the HELAN, BETVU, AMARE, SOLLY, CHEAL and SETGL species by using Colby's formula in comparison to the effect of the components whereas ZEAMA, TRIAE and PISSA were hardly damaged, if at all.

Since the synergistic effect was achieved by using a fourth amount in the combinations as compared to the doses of the herbicidally active ingredients used alone, the lowest dose of the combination (treatment No. 14) could further be diminished.

It can be established from the data of Table that, 5 days after the treatment, medium or strong toxic symptoms appeared on the dicotyledonous -weeds (AM-'H, CHEAL) even under the effect of treatments with bentazon alone; however, CHEAL was killed only by the highest dose of bentazon (2.5 kg/ha of a.i.) whereas the herbicidal effect was diminished by decrease in the dose and became mild by using the lowest doses. Among the monocotyledonous weeds, the highest dose of ethofumesate (1.0 kg/ha of a.i., i.e. treatment No. 7) used alone induced a weak to medium weed control on AVEFA and SETGL whereas the combinations proved to be synergistic on SETGL.

A significant phtotoxicity did not appear on monocotyledonous cultivated plants (ZEAMA, TRIAE) even after 5 days. The sensitivity of pea among the 3 1 23 - dicotyledonous cultivated plants was unaltered. A synergism occurred on HELAN and SOLLY by using any dose of the combinations whereas this was observed on BETH only by using the lowest dose of bentazon (treatment No. 5, i.e. bentazon 0.75 kg/ha of a.i.). Furthermore, it is clear from the evaluation made on the 5th day that the lowest dose of the combination (treatment No. 14) can be further diminished in comparison with the doses of the com- ponents used alone.

It can be observed from the date Of evaluation carried out on the 12th days (Table 4) that the herbicidal effect was not significantly altered, the synergistic effect of Lhe curribination treatments were retained although the p111y'jotc)Y;f.,-J.ty of bentazon used alone increased.

By comparison of Tables 2 and 4 it can be stated that the herbicidal effect of the combination treatments was exerted 10 days earlier than that of the effect of bentazon alone even when used in the highest dose (2.5 kg6ha of a.i., i.e. treatment No. 2) Similarly, the treatment No. 14 shown in Table 3 proves that the a.i. content of the combination can be further diminished.

Example 11

Example 10 was repeated, except that the weight ratio in the combination compositions according Table 5

Herbicidal effect on the test plants on the 15th day after treatment Treatment Dose Wt. ratio of T e s t p 1 a n t s N o kg/ha of bentazon+etho- herbicidal effeci on 172GL HE'LATI PISSA SOLLY C11P.XL AMARE' a. 1. fumesate ZEAMA S" 1 - - 0 0 0 0 0 0 0 2 2P5 - 0 0 3 0 3 3 2/3 3 1,25 - 0 0 3 0 3 2/3 2/3 4 lo - 0 0 3 0 3 2/3 2/3 OP75 - 0 0 3 0 3 2/3 1/2 6 0)5 - 0 0 3 0 2 2/3 1 7 110 - 2/3 2/3 1 0 1 1 1 8 0,5 - 2 1/2 1 0 1 1 0/1 9 0,4 - 1 1 1 0 1 1 0/1 0)3 - 1/2 0 0/1 0 1 1 0 11 0,2 - 1 0 0/1 0 0/1 -0/1 0 12. 2P5+1,0 2 5: 1 2/3 3 3 1 3 3 3 13 1,25+0,5 295:1 1/2 2 3 0 3 3 3 14 - 0 0 0 0 0 0 0 1,0+0,4 2,5:1 2 1 3 0 3 3 3 16 0,75+0,3 295:1 1 2 3 0 3 3 3 17 0,5+0,2 2,5:1 0 1.. 3 0 3 3 2/3 18 1,5+0,2 7,5:1 0/1 1 3 0 3 3 2/3 19 0,5+0,6 OP83:1 2 0 3 0 3 3 1/2 OP75+0p5 1,5:1 0 3 0 3 3 21 1,25+0,3 4,16:1 2 0 3 0 3 3 2 4, - to the invention was changed and the evaluation was made on the 15th day following the treatment (Table 5).

It was stated in the preceeding experiment that the lowest dose used (bentazon+ethofumesate 0.75+0.3 kg/ha of a.i.) could be decreased beyond the weight ratio of 2.5:1. Thus, in the present investigation the herbicidal activity was observed by also using other weight ratios in addition to the decrease in the dose. The results of evaluation carried out on the 15th day are shown in Table 5.

It is obvious from Table 5 that, on diminishing the dose by about 30% (bentazon+ethofumesate 0.5+0.2-kg/ha of a.i.), the herbicidal effect essentially remained equal to the lowest dose (bentazon+ ethofumesate 0. 75+0.3 kg/ha of a.i.) of the preceding experiment and in addition, the synergism on SOLLY, CHEAL and AMARE species was also retained.

It can also be seen from this experiment that the synergistic effect of the combination accord- ing to the invention was retained under wide limits /Irom (0.83 to 7.5):17, particularly on the dicotyledonous CHEAL and AMARE weed species.

Example 12

With the aim to investigate the synergism of combinations of the invention containing various weight ratios of the components depending on the dura1 26 tion of the effect, this experiment was carried out in a maize culture in 4 repetitions on parcels of 10 m 2 size.

The combination showed a synergistic effect on the dicotyledonous AMARE, DATST and HIBTR weed species on the llth day following treatment (see Table 6). Differently from the greenhouse results, a synergism was observed also on the monocotyledonous weed species (DIGSA, ECHCR).

It could be stated on the 53rd day after treatment (Table 7) when the duration of the effect was evaluated that the synergistic effects of the combinations according to the invention wereret2ined both on the dicotyledonous and monocotelydonous weed species mentioned above.

The mild phytotoxicity observed at the first evaluation(on llth day after treatment) which showed symptoms characteristic of ethofumesate, practically ceased at the time of the second evaluation (i.e..

on the 53rd day after treatment).

Example 13

This investigation was carried out by using Imola soy species on 20 cm 2 of black-earth soil contain- ing 2.83 % of organic material and having apH value of 7.09.

The treatment was carried out on September 9th at the wax-maturity state of the cultivated plant.

Table 6

Herbicidal effect on the maize in a small-parcel chemiual weed conirol experiment on the llth day after treatment rreatment NO.

1 Bentazon 2 Ettiofunitsit(-, 3 Bentazon + ethofumesate 4 Bentazon + 5 Bentazon -f 6 e thof umesate ethofumesate Beritazon + ethofumesate 7 Bentazon + ethofumesate 8 Bentazon + ethofumesate 9 Beritazorl Bentazon 11 12 E t I iof te 13 Untreated, frequency % Evaluation % 57.5 Dose Wt. ratio of kg/ha of bentazon+etho a.i. fumesate 2,0 1,0 0,75+0,3 1,0+0,4 1,5+0,6 1,0+0,6 1,0+0,8 1,0+1,0 110 1,5 0,6 0,8 2, 5: 1 2 ' 5:1 1) 2, 5: 1 1, 66: 1 1,25+1 1:1 Herbicidal effert UIARE DATST 11IBTR C nu 97,5,14, 5 C) 100 Phytoto- DIGSA ECHCR xi. city 97P 5 14, G2 80,32 98,01 40,56 38,5 2 61, '25 91,8 96,28 91,87 97,5.

41,25 38, 100 0 31,87 25,09 28,5 221, 5 0 0 43, 06 50,13 43,187 69,6 45 p 36 63t37 68,07 99,25 ) C, 987 "., 98701 96,77 97,01 70,69 74,79 38,25 35,50 3795 5 3, 5' 5 10 0 47,25 24,75 292 8 61 26 46p12 50,66 52,52 2,25 0 52,93 26,35 26,12 50,66 28,35 28,50 0 4,75 1,0 2,5 3,25 2,25 2,5 3,0 0 0 1 1 1 Table 7 Herbicidal effect in the small-parcel experiment on the 53rd day after treatment 1 Treatment Dose Wt. ratio ot Herbicidal. effect Phytoto NO kg/ha of bentazon+etho- xicity % a.i. fumesate AMARE DATST SUVE DIGSA ECHOR SUG1- 1 Bentazon 2,0 100 100 50 54,00.38p00 44,62 0 2 Ethofumesate 110 - 93,36 66',84 78,75 78,75 64s77 76,42 3s75 3 Bentazon + ethofumesate 0,75+0,3 2 # 5: 1 99,00 99)00 65)88 63s.95 80)39 80,94 0 4 Bentazon + ethO:fumesate 1,0+0)4 2, 5: 1 100 100 66 76,17 74,78 73P48 0 Bentazon + ethofijmesate 195+0,6 2, 5: 1 1.00 100, dE3, 34 80,86 90,92 90, 82 1 6 Bentazon + ethofuinusate 1,0+0,6 1p66:1 88P 59 98,5 80304 78p 46 76,31 81,37 1 tli 7 Bentazon + ethoftimesate lt 0+1to 1, 25:1 97951 100 84,37 80,88 88,98 84,28 i CC) 8 Bentazon + ethofumesate 1,0+1,0 78P75 100 85,76 78,08 88v03 83,62 1,5 9 Bentazon Ivo 97,51 100 1993 17,25. 35,0 39 v 37 0 Bentazon 19 5 79p64 72,76 38,0 47,91 42,0 56,19 0 11 Ethofumesate 0,6 31)90 53912 57,9 26,25 59,81 6738 0 12 Ethofumesate ova - 59)50 53,91 69,96 54,69 54,25 55,25 0 13 Untreated, frequency 23,75 32v5 5P0 7)5 22,5 6,25 Evaluationo 11 1 - 29 The spraying was accomplished by using 2 Wander Weil spraying machine, fitted with a spray head, by using 500 1/ha of water.

Immediately before the treatment and then on the 3rd, 5th and 10th days, crop samples were taken from the untreated and test parcels and the dry substance contents of the samples were weighed.

The average results of 4 repetitions for each treatment are summarized in Table S.

Table 8 Effect of the experimental treatments on the water content of the soy crop Treatment No.

Dose 1/ha of a. i.

Water content of the soy crop in % after the treatment on the day 0 3 5 10 0 Untreated control - 51.3 30.3 27.4 26.4 2 Diquat dibromide 0.6 - 29.4 26.1 21.5 3 Bentazon 1.25 - 22.5 19.8 19.5 4 Ethofumesate 0.5 - 23.8 20.9 19.3 Bentazon+etho fumesate 1.25+0.5 - 23.5 20.2 16.3 a - It appears from the data of Table 8 that under the effect of the experimental treatment, the water content of the soy seeds was more rapidly decreased than by using the reference diquat dibromide (treatment No. 2) even at the evaluation carried out on the 3rd day.

This tendency was further strengthened on the 5th day following treatment. Similarly, the water content of the crop was more strongly diminished in the experimental treatment as compared to the reference 0.6 1/ha of diquat dibromide in the samples taken on the 10th day. However, at this time it could also be observed that the water content of the soy seed was diminished to a significantly greater degree by the e5perj.7 mental combination (bentazon+ethofumesate 1.25+0.5 1/ha) than by the components alone (bentazon 1.25 1/ha and ethofumesate 0.5 1/ha).

A is 31

Claims (18)

Claims

1. Herbicide and growth-regulating compositions, which comprise a) 3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one-2,2- dioxide and b) ( )-2-ethoxy-2,3-dihydro-3,3-dimethylbenzofuran-5-yl methanesulfonate or Lny enantioner thereof.

2. Compositions as claimed in claim 1, which comprise a) 3-isopropyl-lH-2,1,3-benzothiadiazin-4(3HO-one-2,2- dioxide and b) ( )-2-ethoxy-2,3-dihydro-3,3-dimethylbenzofuran-5-yl methanesulfonate or any enantiomer thereof in admixture with one or more solid and/or liquid carrier (s) or inert solvent(s) the active ingredients being present in an amount of 0.1 to 95% by weight of the composition and in a weight ratio of a): b) of 10:1 to 0.4:1.

3. Compositions as claimed in claim 1 or claim 2 the grist of native mineral or synthetic are also present.

4. Compositions as claimed in any of claims 1 to 3 the inert solvent(s) are xylene or cyclohexanone.

Compositions as claimed in any of claims 1 to 4 a surfactant is also present.

Compositions as claimed in any of claims 1 to

5 wherein anionic or nonionic emulsifying or dispersing agents are also present.

X, 20 wherein materials wherein 5.

wherein

6.

t :' 15 32

7. A method of controlling weeds which comprises applying to said weeds a solution of a composition as claimed in any of claims 1 to 6.

8. A method of controlling weeds as claimed in claim 7 which comprises treating the cultivated plants in their 1 to 6- foliage-leaf state by using 50 to 1000 litre/hectare of a spray solution of the composition as claimed in any of claims 1 to 6 containing 0.1 to 12 % by weight of active ingredient.

9. A method as claimed in claim 7 or claim 8 wherein from 50 to 300 1/ha of spray solution are employed.

10. A method as claimed in any of claims 7 to 9 wherein the active ingredients are administered in an amount of from 0.5 to 5 kg/ha.

11. A method as claimed in any of claims 7 to 9 wherein the active ingredients are administered in an amount of from 1 to 4 kg/ha.

12. A method of desiccating and/or defoliating cultivated plants, particularly maize, soy, sunflower, potato, flax and hemp, which comprises treating said cultivated plants with a solution of a composition according to any of claims 1 to 6 up to 1 to 4 weeks before harvesting a crop derived from said plants.

13. A method as claimed in claim 12 wherein said plants are treated with a spray solution at a level of from 50 to 300 1/ha.

1 0 33

14. A method as claimed in claim 12 or claim 13 wherein said solution contains from 0.1 to 12% by weigh of active ingredient.

15. Compositions as claimed in claim 1 5 substantially as hereinbefore described.

16. Compositions as claimed in claim 1 substantially as hereinbefore described and with reference to any of the Examples.

17. A method as claimed in claim 7 or claim 12 10 substantially as hereinbefore described.

18. A method as claimed in claim 7 or claim 12 substantially as hereinbefore described and with reference to any of the Examples.

Published 1990at The Petent Office. State House.66 71 High Hclborr. LcndonWC I R4TF Further copies May be obtainedf.-om The Sales Branch. St Ylar7 Cray- Orpington Kent BR5 3RD Printcd by techniques td. St Mai:,, Cra,.-- Ker.,. Ccr. 1 8-