AU4239499A

AU4239499A - Aqueous suspension concentrate comprising thidiazuron and ethephon

Info

Publication number: AU4239499A
Application number: AU42394/99A
Authority: AU
Inventors: Frank Sixl
Original assignee: Bayer CropScience AG
Current assignee: Bayer CropScience AG
Priority date: 1998-07-31
Filing date: 1999-07-30
Publication date: 2000-02-24
Anticipated expiration: 2019-07-30
Also published as: ES2195483T3; DE19834598A1; AR029309A1; EP0976329B1; BR9903257A; AU764967B2; EP0976329A1

Description

r/UU/U I I 28/5/91 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: AQUEOUS SUSPENSION CONCENTRATE COMPRISING THIDIAZURON AND ETHEPHON

C

The following statement is a full description of this invention, including the best method of performing it known to us Hoechst Schering AgrEvo GmbH AGR 98/M 223 Dr. RI/we Description Aqueous suspension concentrate comprising thidiazuron and ethephon The invention relates to the field of plant growth regulators/defoliants, in particular to mixtures of thidiazuron and ethephon.

For a long time, thidiazuron and ethephon have been known as plant growth regulators/defoliants, in particular for use in crops of cotton (see, for example, The Pesticide Manual, 11th Edition, British Crop Protection Council, Farnham, 1997, thidiazuron entry number 703, ethephon entry number 281).

DE-A-26 46 712 discloses mixtures of thidiazuron and ethephon, and a good synergistic effect for the use as defoliant in cotton is demonstrated.

However, until now such mixtures have only been used as so-called tank mixes, which means that the mixture components are admixed only shortly prior to application.

Surprisingly, it has now been found that stable, storable suspension concentrates of thidiazuron and ethephon can be prepared. Owing to the differing stability of the two substances in acidic medium, this was unexpected. The Pesticide Manual states a storage stability in a pH range from 5 to 9 for thidiazuron, and at a pH of below 5 for ethephon.

The invention accordingly provides a suspension concentrate, comprising a) thidiazuron and ethephon, b) one or more surfactants, c) one or more thickeners and d) water.

By providing the suspension concentrates according to the invention, the disadvantages of the customary tank mixes, such as insufficient dosage reliability and low handling safety, are overcome. Furthermore, the concentrates have the advantage of reduced packaging costs.

The concentrates generally have a pH of 5, preferably g 2.

The active compounds used are known and commercially available; thidiazuron from AgrEvo, Frankfurt, Germany, and ethephon, for example, from Rhone-Poulenc, Lyon, France (see, for example, the pesticide manual and the literature mentioned therein).

C..

The active compounds are generally employed in a mass ratio of thidiazuron:ethephon of 1:5-30, preferably 1:5-15, particularly preferably 1:8-12.

The proportion of the active compounds in the suspension concentrate is generally from 5 to 80% by weight, preferably from 15 to 60% by weight.

The concentrates according to the invention may comprise, as surfactant which 20 helps to improve the dispersion properties of the particles in the solid suspension, for example a dodecyl- or tridecylbenzenesulfonate in a proportion of preferably S. from 0.01 to 12% by weight. Thus, it is possible to employ, for example, ®Maranil S: (dodecylbenzenesulfonate, Na salt) from Henkel, Dusseldorf, Germany, as paste or powder.

Suitable surfactants are furthermore polyacrylic acid derivatives, such as those which are obtainable, for example, under the trade names ®Sokalan CP 10 (BASF), the "Geropon series (HB, DA, DG) (Rh6ne-Poulenc) or the ®Dispersant series (Rh6ne-Poulenc) or the ®Degapas series (Degussa, Frankfurt, Germany).

®Sokalan CP 10 is a modified Na polyacrylate having a low molecular mass which is prepared by a special polymerization process (BASF, Ludwigshafen, Germany) Techn. Info TI/P 3039 d from 1988.

The ®Geropon products HB, DA and DG and ®Dispersant HB and FB are, according to the Rh6ne-Poulenc data sheet from 1979 and 1989 respectively, alkali metal polyacrylates, which are available both in liquid and solid form.

The ®Degapass series likewise consists of alkali metal and ammonium salts of polyacrylic acid derivatives.

Preferred surfactants are ethoxylated tristyrylphenols. In general, 0.1 to 30% by weight, preferably 0.5 to 20% by weight, of the surfactant or the surfactant mixture are added. In the case of the tristyrylphenol derivatives, the degree of ethoxylation S: can be between 10 and 40, but is preferably between 14 and 28. The tristyrylphenol 15 derivatives are sold, for example, under the trade names ®Soprophor FL, ®Soprophor CY/8, ®Soprophor S/25, ®Soprophor FL/60, ®Soprophor FLK (Rhone- Poulenc), Hoe S 2374, Hoe S 3475, Hoe S 3775 (Clariant, Basle, Switzerland).

Particular preference is given to nonionic surfactants, and ®Soprophor S/25 is very 20 particularly preferred.

The thickeners used according to the invention may be inorganic or organic in nature; they can also be combined. Suitable thickeners are, for example, those based on aluminum; xanthan, methylcellulose, polysaccharide, for example alginate, alkaline earth silicate, gelatin and polyvinyl alcohol, such as montmorillonites and their organic derivatives, for example ®Bentone EW and ®Bentone LT, Veegum, ®Rhodopol 23, ®Kelzan S or Satiaxan. Preference is given to polysaccharide-based thickeners.

The proportion of the thickener in the suspension concentrate is generally from 0.05 to 0.5% by weight, preferably from 0.1 to 0.2% by weight.

The suspension concentrate according to the invention preferably comprises one or more fillers, for example those based on silica, such as non-water-swellable kieselguhr (for example ®Diamol, from Bertram, Hamburg, Germany), or clay minerals, such as ®Kaolin 1777.

The preferred filler is ®Diamol.

The filler is generally added in an amount of from 2 to 50% by weight, preferably from 5 to 20% by weight.

Concentrates which comprise a filler generally have advantages with respect to sedimentation rate, formation of sediments and phase separation.

Furthermore, it is possible to add to the concentrate according to the invention additionally up to 25% by weight, preferably up to 15% by weight, of commercial .15 auxiliaries, such as wetting agents, defoamers, preservatives and/or antifreeze agents.

Suitable additional wetting agents are, for example, tributylphenol polyglycol ethers, such as the ®Sapogenat T brands (Clariant) or nonylphenol polyglycol ethers, such 20 as the Arkopal N brands (Clariant).

Suitable defoamers are, for example, those based on silicone, such as those of the ®Silcoolapse series (Rhine-Poulenc), SE 39 or Antischaumittel SH (Wacker).

If required, preservatives, for example those based on formaldehyde, benzoic acid and triphenyltin, are used, for example ®Kobate C.

It is furthermore also possible to add antifreeze agents, such as urea, salts, polyols (for example glycol, propylene glycol or glycerol) or sugars.

To prepare the suspension concentrates according to the invention, the components are stirred, for example with water, and the resulting coarse suspension is comminuted, if appropriate, by grinding, for example in a corundum or toothed-disk mill, to a fineness of approximately 200 pm, and the product is subsequently ground, for example in attrition bead mills or sand mills, until the particles of the suspension are preferably present in particle sizes of from 0.1 to 10 pm, particularly preferably of below 5 pm. The particle size is determined using, for example, a disk centrifuge or a Coulter counter.

Such a process likewise forms part of the subject matter of the invention, as do suspension concentrates which are obtainable by this process.

The suspension concentrate of the invention is applied in a simple manner by S diluting the concentrate with the desired amount of water, stirring and applying to ."15 the plant. The spray liquors obtained from the concentrates according to the invention are distinguished in particular by a uniform distribution of the active compounds, which remains even after standing for 24 hours.

The suspension concentrate according to the invention is particularly suitable for the 20 defoliation and for accelerating the opening of the capsule of cotton plants, which makes the use of harvesting machines considerably easier.

However, the concentrate according to the invention is also suitable for influencing the growth or for defoliating other plants.

The invention also provides a method of regulating the growth/defoliation of plants, which comprises treating the plant with an undiluted or diluted suspension concentrate according to the invention.

Dilution is preferably carried out using water, and the plant is preferably a cotton plant.

6 The invention also provides the use of a suspension concentrate according to the invention for regulating the growth/for the defoliation of a plant, preferably a cotton plant.

The application rate of the concentrate can vary within wide limits, depending on external conditions, such as temperature and humidity; it is generally from 1 to 10,000 g of total active compound/ha, preferably from 1 g to 1000 g of total active compound/ha.

Application is usually carried out after dilution with water, using, in general, from 100 to 1000 I of spray liquor per hectare. Use by the so-called LV (low volume) or ULV (ultra low volume) methods is also possible.

The concentrate according to the invention can optionally, depending on the intended purpose, be used in combination with other active compounds, such as other defoliants and crop protection agents (herbicides, insecticides, fungicides, etc.).

*Q S S. Se Activity and speed of action can optionally also be increased using additives, such as organic solvents, wetting agents and oils, which allows the required application rate to be reduced.

Of course, it is also possible to use the concentrate according to the invention for treating genetically modified plants, in particular genetically modified cotton, which contain, for example, one or more foreign genes to obtain resistance to insecticides and/or herbicides.

The content of the German Patent Application 198 34 598.4, the priority date of which is claimed by the present application, and the enclosed abstract is expressly referred to; it is incorporated into the description by reference.

The invention is illustrated in more detail by the examples, without limiting it thereby.

Examples Example 1 Formulation 1: a.

a. a a. a a..

2 a. *a Ga a Component by weight Ethephon 36.00 Thidiazuron 3.00 ®Soprophor S25 5.00 Satiaxane 0.20

H

2 0 55.80 Storage stability of formulation 1: Time by weight of thidiazuron Initial value 3.09 2 weeks at RT 3.09 2 weeks at 40 0 C 3.07 2 weeks at 54 0 C 3.05 8 weeks at RT 3.04 8 weeks at 40°C 3.04 8 weeks at 54 0 C 2.96 Example 2 Formulation 2: Component by weight Ethephon 36.00 Thidiazuron 3.00 ®Soprophor S25 5.00 OBentone LT 0.20

H

2 0 55.80 as. 0 20 Storage stability of formulation 2: Time by weight of thidiazuron Initial value 3.06 2 weeks at RT 3.02 2 weeks at 40 0 C 3.01 2 weeks at 54 0 C 3.00 8 weeks at RT 3.02 8 weeks at 40 0 C 3.00 8 weeks at 54 0 C 2.93 Example 3: Formulation 3: Component by weight Thidiazuron 2.50 Ethephon 30.00 ®Soprophor S25 4.17 "Diamol 16.66 Satiaxane (x 91) 0.17

H

2 0 (demineralized) 46.50 *5

S

S *a

S

Formulation 3 showed a particularly low sedimentation rate, neither formation of sediment nor phase separation was observed.

"Comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Claims

1. A suspension concentrate comprising a) thidiazuron and ethephon, b) one or more surfactants, c) one or more thickeners and d) water.

2. The suspension concentrate as claimed in claim 1, wherein the active compounds thidiazuron and ethephon are present in a mass ratio of 1:5 to a:*

3. The suspension concentrate as claimed in claim 1 or 2, which comprises one 9 or more nonionic surfactants. 9

4. The suspension concentrate as claimed in claim 3, wherein the surfactant is an ethoxylated tristyrylphenol. 99 The suspension concentrate as claimed in one or more of claims 1 to 4, S. 20 which additionally comprises a filler.

6. The suspension concentrate as claimed in one or more of claims 1 to which comprises one or more further auxiliaries selected from the group consisting of wetting agents, defoamers, preservatives and/or antifreeze agents.

7. A process for preparing a suspension concentrate as claimed in one or more of claims 1 to 6, which comprises mixing up the components and, if appropriate, comminuting and grinding the resulting suspension. 11

8. The process as claimed in claim 8, wherein the suspension concentrate is ground to a particle size of from 0.1 to 10 pm.

9. A suspension concentrate obtainable by mixing a) thidiazuron and ethephon, b) one or more surfactants, c) one or more thickeners and d) water, and, if appropriate, comminuting and grinding the resulting suspension. A method of regulating the growth/defoliation of a plant, which comprises treating the plant with an undiluted or diluted suspension concentrate as claimed in one or more of claims 1 to 6 and/or 9. s

11. The method as claimed in claim 7, wherein the plant is a cotton plant. f**

12. The method as claimed in claim 8, wherein the cotton plant has been genetically modified. 20 13. The use of a suspension concentrate as claimed in one or more of claims 1 to 6 and/or 9 for regulating the growth/defoliation of a plant, in particular a ****cotton plant. 0o DATED this 30th day of July 1999. HOECHST SCHERING AGREVO GMBH WATERMARK PATENT TRADEMARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN. VIC. 3122.