MXPA00002508A - Defoliant - Google Patents

Abstract

A mixture comprising (A) thidiazoron or thidiazuron and diuron and (B) cyclanilide or cyclanilide and ethephon is suitable for effecting leaf abscission of plants, in particular in crops of cotton.

Description

PEFOL ANTE DESCRIPTIVE MEMORY The invention relates to the field of defoliants, especially to mixtures containing thidiazuron, and to its use in cotton crops. Thidiazuron has been known for some time as a defoliant, especially for use in cotton crops (see, for example, "The Pesticide Manual", 11th edition, British Crop Protection Council, Farnham 1997). The use of tiadizuron in mixtures is also described; see, for example, DE-A 26 46 712. However, since the demands on modern defoliants, from the economic and ecological point of view, they are continuously growing as regards, for example, activity, amount to apply, residues, toxicity and advantageous aptitude for the preparation, there is a permanent task to develop, for example by means of the combination of known active substances, new defoliants which present advantages, at least in partial aspects, compared to those known. It was now found, surprisingly, that thidiazuron and mixtures already commercially employed of thidiazuron and diuron in admixture with cyclanilide or cyclanilide / ethephon, exhibit synergistic activities.

The object of the invention is, therefore, a mixture containing (A) thidiazuron or thidiazuron and diuron, and (B) cyclanilide or cyclanilide and ethephon. The mixtures according to the invention are especially suitable for use as defoliants in cotton crops, for example by rapid and / or high activity or smaller application quantities. The term "defoliant" in the sense of the invention is synonymous with "defoliating agent" or "desiccant" and also comprises the known regulatory action of the growth of thidiazuron and mixtures containing thidiazuron. The active substances used (ai) are known and commercially available, thidiazuron, cyclanilide and ethephon from Aventis Crop Science, France, and diuron from Griffin, USA. The active substances are described, for example, with indications for preparation, mixing and handling, in "The Pesticide Manual" (v. ant.) and have the following registration numbers there: thidiazuron 703, diuron 260, cyclanilide 170 and ethephon 281. Mixtures of thidiazuron and diuron are commercially available under the designation Drop Ultra® (Aventis Crop Science, France). Such mixtures are described, for example, in US-A 4,613,354. It is preferred as component (A) thidiazuron. Preferred as component (B) is cyclanilide.

The combination of active substances can be used in a customary manner, for example by spray application of a spray mixture prepared in tank mixture from individual formulations of the active substances or from a spray mixture prepared by dilution with water of a mixed formulation of the active substances. For the application, first of all, those methods that are customary for the application of the individual active substances and make a common application are possible. The application can also be carried out, in principle, by consecutive applications of the individual active substances, and the possible separation in time can be determined in simple routine preliminary tests. However, common application is preferred. The active substances can optionally also be used in combination with other plant protection active substances. For the same activity, the amount to be applied of an individual active substance in the combination decreases considerably compared to the amount to be applied of the respective individual active substance in the application alone. The optimal choice of the weight ratio and the quantities to be applied depend, for example, on the stage of development, on environmental factors and climatic conditions or, also, on the class of active plant protection substances optionally used additionally and can be quickly determined in simple routine tests by the specialist in the field.

The amount to be applied for component (A) is generally in the range of 1 to 500 g / active substance (= i.a.) / ha. For thidiazuron, it is preferably in the range of 10 to 500 g ai / ha, particularly preferably 10 to 300 g ai / ha, very particularly preferably 20 to 200 g ai / ha, especially 20 a 150 g of ai / ha. For thidiazuron / diuron mixtures (typically in the weight ratio 2: 1) the amount to be applied is generally in the range of 10 to 500 g ai / ha, preferably from 15 to 300 g ai / ha, particularly preferably from 20 to 200 g ai / ha, with very special preference from 30 to 200 g ai / ha, especially from 30 to 150 g of ia / ha. The amounts to be applied for the component (B) can vary between wide limits and are generally between 0.1 and 5,000 g of i.a./ha. For the component (B) are preferred as quantities to be applied, for example: Cyclanilide: from 40 to 400 g of i.a./ha, especially preferably from 90 to 240 g of i.a./ha. Cyclinilide / ethephon mixture (typically 1: 8): from 500 to 4000 g of i.a./ha, with particular preference from 800 g to 2,500 g of i.a./ha. The weight ratios of the components (A) :( B) can vary between wide limits, being generally between 1: 100 and 100: 1.

Preferably, the approximate ratio (A) :( B) is for cyclanilide: 0.1-2: 1, particularly preferably 1: 2; for cyclanilide / ethephon: 0.1-2: 1; The invention also relates to defoliants, that is to say agents for causing the fall of the leaves of plants, which contain combinations of the active substances (A) and (B) as well as customary processing aids. The combinations according to the invention and their individual active substances can be formulated in various ways, according to what biological and / or chemical-physical parameters are intended. Possible formulation possibilities are, for example: wettable powders for spraying (WP), water-soluble powders (SP), water-soluble concentrates, emulsifiable concentrates (EC), emulsions (EW), and oil-in-water emulsions. Water-in-oil emulsions, sprayable solutions, suspension concentrates (SC), oil-based or water-based dispersions, oil-miscible solutions, capsule suspensions (CS), powders (DP), granules (GR) in the form of microgranules, spray granules, granules, adsorption granules and granules, water-dispersible granules (WG), water-soluble granules (SG), ULV formulations (ultra-low-volume), microcapsules and WSB (water -soluble bags ("water soluble bags")). The individual types of formulation are known in principle and are described, for example, in: Winnacker-Küchler, "Chemische Technologie", volume 7, C. Hauser Verlag München, 4th Ed. 1986, Wade van Valkenburg, "Pesticide Formulations", Marcel Dekker, NY, 1973; K. Martens, "Spray Drying" Handbook, 3rd Ed. 1979, G. Goodwin Ltd. London. The necessary formulation aids, such as inert materials, surfactants, solvents and other additives are also known and are described, for example, in: Watkins, "Handbook of lnsectic.de Dust Diluents and Carriers", 2nd Ed., Darland Books , Caldweil NJ, H. v. Olphen "Introduction to Clay Colloid Chemistry"; 2nd Ed. J. Wiley «St Sons, N. Y .; C. Marsden, "Solvents Guide"; 2nd Ed., Interscience, N. Y. 1963; McCutcheon's "Detergents and Emulsifiers Annual", MC Publ. Corp., Ridgewood N. J .; Sisley and Wood "Encyclopedia of Surface Active Agents", Chem. Publ. Co. Inc., N. Y. 1964; Schonfeldt, "Grenzfláchenaktive Áthylenoxidaddukte", Wiss. Verlagsgesell., Stuttgart 1976; Winnacker-Küchler, "Chemische Technologie", volume 7, C. Hauser Verlag München, 4th Ed. 1986. Based on these formulations, combinations can also be prepared with other crop protection agents such as insecticides, acaricides, herbicides, fungicides, protectants, other regulators of growth and / or credits, for example in the form of a finished formulation or as a tank mixture. The wettable powders for spray are prepared homogeneously dispersible in water which, together with the active substance contain, in addition to a diluent or inert substance, ionic and / or nonionic surfactants (wetting agent, dispersing agent), for example alkylphenols polyoxyethylated, polyoxyethylated fatty alcohols, polyoxyethylated fatty amines, fatty alcohol polyglycol ether sulphates, alkane sulphonates, alkylbenzene sulfonates, sodium ligninsulfonate, sodium 2,2'-dinaphthylmethane-6,6'-disulfonate, sodium dibutylnaphthalene sulfonate or also sodium oleoylmethyltaurate. For the preparation of wettable powders for spraying, the active substances are ground finely, for example in conventional apparatus such as hammer blowers, blow moulders and air jet mills, and simultaneously or subsequently mixed with the formulation aids. The emulsifiable concentrates are prepared by dissolving the active substance in an organic solvent, for example butanol, cyclohexanone, dimethylformamide, xylene or also aromatics or high-boiling hydrocarbons or mixtures of organic solvents, with the addition of one or more surfactants. of ionic and / or nonionic type (emulsifiers). As emulsifiers, for example, calcium salts of alkylarylsulphonic acids such as Ca dodecylbenzenesulfonate, or nonionic emulsifiers such as polyglycol esters of fatty acids, alkylaryl polyglycol ethers, polyglycol ethers of fatty alcohols, condensation products of propylene oxide-ethylene oxide, alkyl polyesters can be used. , sorbitan esters, such as sorbitan esters of fatty acids or polyoxyethylene sorbitan ethers, such as polyoxyethylene sorbitan esters of fatty acids.

Powdered agents are prepared, e.g. eg, by grinding the active substance with finely divided solid substances, e.g. ex. talc, natural clays such as kaolin, bentonite and pyrophyllite, or diatomaceous earth. The suspension concentrates can be water or oil based. They can be prepared, for example, by wet grinding by means of conventional commercial bead mills and optional addition of surfactants such as, eg, those that are already indicated in the other types of formulation. The emulsions, p. ex. oil-in-water / EW emulsions) can be prepared, for example, by means of stirrers, colloid mills and / or static kneaders with the use of aqueous organic solvents and optionally surfactants such as. eg, those that are already indicated in the other types of formulation. The granulates can be prepared, either by spraying the active substance on an absorbent granular inert material or by applying concentrates of active substance by means of adhesive agents, e.g. ex. polyvinyl alcohol, sodium polyacrylate or also mineral oils, on the surface of carrier substances such as sand, kaolinite or granulated inert material. The active substances can also be granulated in the usual way for the preparation of fertilizer granules. The water-dispersible granules are generally propagated by the usual processes such as spray drying, fluidized-bed granulation, plate granulation, mixing in high-speed kneaders and extrusion without solid inert material.

The mixtures according to the invention generally contain 0.1 to 99% by weight, in particular 0.1 to 95% of active substances of the components (A) and (B). In wetting powders for spraying, the concentration of active substance is, eg. eg, from about 10 to 90% by weight, the rest consisting of up to 100% by weight in usual formulation components, in the emulsifiable concentrates, the concentration of active substance can be from about 1 to 90% by weight. The powder formulations contain, e.g. eg, from 1 to 80% by weight of active substance, preferably most of the time from 5 to 60% by weight of active substance. Sprayable solutions contain, for example, from 0.05 to 80% by weight, most of the time from 2 to 50%, of active substances. In the water-dispersible granules, the content of active substance depends in part on whether the active compound is present in liquid or solid form and on which granulation aids, fillers, etc. are used. In water-dispersible granules, the content of active substance is, for example, between 1 and 95% by weight, most often between 10 and 80% by weight. In addition, the aforementioned active substance formulations optionally contain the respective customary adhesives, wetting agents, dispersants, emulsifiers, preservatives, antifreezes and solvents, fillers, carriers and dyes, defoamers, evaporation inhibitors and agents influencing the pH value and the viscosity. As active ingredients for the active substances according to the invention in mixture formulations or in tank mixtures, active substances known, for example, as described, for example, can also be used. eg, in Weed Research 26, 441-445 (1986) or "The Pesticide Manual ", 11th edition, 1997, and bibliography cited therein For the application, formulations that are in the usual form of trade are eventually diluted in the usual way, eg with water in the wetting powder for spraying, emulsifiable concentrates, dispersions and granules dispersible in water and then applied to the plants.This also includes special application variants, such as those customary especially in cotton cultivation, p. eg, the application with fumigation aircraft. Powdered preparations, granules for application on the ground or by spreading, as well as sprayable solutions, are usually no longer diluted with other inert substances before application. It is also an object of the invention to use the mixtures or agents according to the invention as defoliants, that is to say to cause the fall of the leaves of the plants, preferably in suitable crops of useful plants, such as cotton sunflowers or potatoes. The defoliant use in cotton crops is especially preferred: Another object of the invention is a method for causing the fall of the leaves of a plant, preferably of a useful plant, with particular preference of a cotton plant, characterized in that the plant is treated with a mixture according to the invention or with an agent according to the invention. Naturally, the mixtures, or agents, and the process can also be used for the treatment of genetically modified (transgenic) plants, preferably of useful plants, with particular preference of cotton plants, said plants containing, for example, one or several genes strangers for the attainment of resistance to insecticides and / or herbicides. Hereby express reference is made to the content of the German patent application 199 11 165.0 and the attacabstract; serves by appointment as a component part of this specification. The invention is explained in more detail by the examples, without limiting it.

EXAMPLES 1. Appreciation of the activity and evaluation of the synergism The activity in the plants is evaluated after the fall of the leaves according to a scale from 0 to 100%: 0% = no recognizable activity in comparison with the untreated plants; 100% = all the leaves detac An estimate of the synergism for the active substances used here must take into account the considerably different applied amounts of the individual active substances. Therefore, it is not convenient to buy the activities of the combinations of active substances and those of the individual active substances for respectively equal amounts applied. The quantities of active substances which are saved according to the invention can be recognized by the superadditive increase in activity with the use of combined application quantities, or by reduction of the applied amounts of the two individual active substances, in the combined use in comparison with the quantities of active substances applied in the individual application for equal activities. In the combinations, it is differentiated in all cases between the degree of activity calculated and that found. In most chaos, the synergistic increase in activity is so high that the activity of the combination clearly exceeds the formal (arithmetic) sum of activities of the individual substances. On the basis of the known activities of the individual active substances, no such high activity increase was to be expected. The degree of activity to be expected theoretically from a combination can be estimated approximately by the SR Colby formula (see "Calculation of synergistic and antagonistic responses of herbicide combinations" ("Calculation of synergistic and antagonistic responses of herbicide combinations"), Weeds 15 (1967), pages 20-22) This formula expresses for binary combinations: X • Y E = X + Y - - 10 ° where X =% activity by A, for an applied amount of x Kg / ha; Y =% activity by B for an applied amount of y Kg / ha; E = the activity to wait for A + B for x + y kg / ha. If the activity is greater than what can be expected by calculation, then the activity of the combination is greater than the additive, that is, an effect of synergistic activity is present. 2. - Activity as a defoliant 2.1. Operative procedure Seeds of cotton of the Vulcan class were seeded at a depth of 1 cm and were grown in a climate chamber (14 h light, daytime temperature: 25 ° C, overnight 18 ° C) to the 8-10 leaf stage.

TABLE 1 2. 2. (Mixtures with cyclanilide) The application was made with a laboratory overhead sprinkler by means of a Teejet 11002XR nozzle, with an amount of 300 l / ha * Drop® WP ** Drop Ultra® SC The tests show a clear synergy.

Claims (10)

NOVEDAP PE THE INVENTION CLAIMS

1. - A mixture, which contains: (A) thidiazuron or thidiazuron and diuron, and (B) cyclanilide or cyclanilide and ethephon.

2. The mixture according to claim 1, further characterized in that the component (A) is thidiazuron.

3. The mixture according to claim 1 or 2 further characterized in that the component (B) is cyclanilide.

4. The use of the mixture according to one or more of claims 1 to 3 to cause the fall of the leaves of the plants.

5. The use according to claim 4, further characterized in that the plants are cotton plants.

6. The use according to claim 5, further characterized in that the cotton plants are transgenic cotton plants.

7.- A defoliant, which contains: (A) thidiazuron or thidiazuron and diuron, (B) cyclanilide or cyclanilide and ethephon, and (C) one or more formulation aids.

8. A method for causing the leaves to fall on plants, further characterized in that the plants are treated with the mixture according to one or more of claims 1 to 3 or the agent according to claim 7.

9. - The method according to claim 8, further characterized in that the plant is a cotton plant.

10. The method according to claim 9, further characterized in that the cotton plant is a transgenic cotton plant.