MXPA99003275A - Fungicidal compositions of ditiocarbamate, with improved properties - Google Patents

Abstract

The present invention relates to: fungicidal dithiocarbamate formulations, which have improved physical properties. The formulations comprise one or more dithiocarbamate fungicides and a water soluble polymer.

Description

FUNGICIDAL COMPOSITIONS OF DITIOCARBAMATE.

WITH IMPROVED PROPERTIES This invention relates to fungicidal dithiocarbamate formulations, which have improved physical properties. Dithiocarbamates, and their derivatives, are a class of useful fungicides in the control of phytopathogenic fungi. Due, in part, to their physico-chemical properties, the dithiocarbamate compositions are often provided in dry form, such as, for example, powders mixable with water, powders and granules, and as suspension concentrates, such as aqueous formulations that can flow. A number of additives have been investigated to improve the efficacy of such formulations through improvements in the physical / chemical properties of the composition or to improve the availability of the dithiocarbamate after application. One such additive is polyvinyl alcohol. French patent 1493069 discloses the use of polyvinyl alcohol ("PVA") with a molecular weight greater than 100,000 daltons and which is hydrolyzed by more than 95% to increase the affinity of a fungicide for foliage. The Canadian patent 1,328,599 discloses the use of PVC with a molecular weight greater than 80,000, to increase the firmness in the rain of the dithiocarbamates. Unfortunately, medium to high molecular weight PVAs cause severe formulation problems with dithiocarbamates, which manifest as low suspension capacity and aggregate in dry formulations, such as water miscible powders and dispersible granules, and the formation of gel in concentrates in aqueous suspension. It is generally accepted that the medium to high molecular weight is necessary for the adhesion of particles under wet conditions. Therefore, there is a need for dithiocarbamate formulation additives that provide the advantages of high molecular weight PVA, without degrading the physical / chemical properties of the formulation. It has surprisingly been found that even very low molecular weight PVAs can impart significant adhesion in the fungicidal formulations of dithiocarbamate, while maintaining, or even improving, many of the physical properties. In addition, it has been found that the Low molecular weight PVA very well disperses dithiocarbamate particles on the leaf surface and allows a much better redistribution of these particles under wet conditions than higher molecular weight PVA. Redistribution is important for the increased activity and efficacy of contact fungicides, such as dithiocarbamates. This invention provides a composition comprising: a) one or more dithiocarbamate fungicides; and b) polyvinyl alcohol with a molecular weight of 10,000 to 80,000, a hydrolysis level of 77 to 95 percent and a particle size of less than 800 microns. Preferably, the dithiocarbamate fungicide is selected from mancozeb (a coordination product of zinc ions and the manganese-ethylene bisdithiocarbamate), maneb (manganese ethylenebisdithiocarbamate), zineb (zinc ethylenebisdithiocarbamate), ziram (zinc dimethyldithiocarbamate) , propineb ([[(1-methyl-1, 2-ethanediyl) bis- [carbamatethioate]] (2-)] zinc homopolymer, metiram (tris [amine- [ethylene-bis (dithiocarbamate)] zinc (II)] - [tetrahydro-1, 2,4, 7-dithiadiazocin-3, 8 -dithine] polymer), thiram (bis (dimethylthiocarbamoyl) disulfide), ferbam (ferric dimethyldithiocarbamate), metham (sodium N-methyldithiocarbamate) and dazomet (tetrahydro-3,5-dimethyl-1,3,5-thiadiazine-2-thione). The dithiocarbamate may be in the form of a powder mixable with water, a powder or granular formulation or a concentrate in aqueous suspension. Water-miscible powder or granular formulations are preferred. Also, the composition itself can be in the form of a powder mixable with water, a powder or granular formulation or an aqueous suspension concentrate. The composition may contain from 1 to 95% by weight of the dithiocarbamate, preferably from 50 to 85%, more preferably from 60 to 80%. PVA polymers useful in this invention, have a molecular weight in the range of 10,000 to 80,000 Daltons (ie a viscosity of the solution at 4% of <20 cp), more preferably in the range of 10,000 to 50,000 and especially preferred in the range of 15,000 to 25,000. The level of acceptable PVA hydrolysis is in the range of 77 to 95% (i.e., a saponification number between 150 and 30), more preferably in the range of 80 to 90% and especially preferred in the range of 86 to 89%. PVA can be added at levels of 0.1 to 2.0%, based on the weight of the formulation. The most preferred range is from 0.2 to 1.0% and the especially preferred range is from 0.3 to 0.7%, based on the weight of the formulation. For water miscible powders, dispersible granules and other dry formulations, the PVA can be dry blended with the formulation or dissolved in water and mixed with an aqueous dithiocarbamate composition, before drying. In the case of concentrates in aqueous suspension, the PVA can be dissolved in the aqueous phase at any point in the formulation process. The preferred method is to dissolve the PVA in the aqueous phase, in order to ensure uniform distribution of the polymer in the formulation. The average particle size of the PVA should be less than 800 microns in diameter, more preferably less than 500 microns and especially preferred less than 250 microns in diameter, to aid in dissolution. For some applications, one or more other pesticides may be added to the dithiocarbamates of the present invention, thus providing advantages and additional effectiveness. When mixtures of pesticides are used, the relative proportions used depend on the relative effectiveness of each pesticide in the mixture with respect to the fungi, weeds and insects that are controlled. Examples of other fungicides that can be combined with the dithiocarbamates of the present invention include, for example: a) nitrophenol derivatives, such as dinocap, binapacryl and 2-sec carbonate. -butyl-4,6-dinitrophenyl-isopropyl; (b) heterocyclic structures, such as captan, folpet, glyodine, dithianon, thioquinox, benomyl, thiabendazole, vinolozolin, iprodione, procymidone, triadimenol, triadimefon, bitertanol, fluoroimide, triarimol, cycloheximide, ethirimol, dodemorph, dimethomorph, thifluzamide and quinomethionate; (c) various halogenated fungicides, such as chloranil, chlorothalonil, dichlone, chloroneb, dichloran and polychloronitrobenzenes; (d) fungicidal antibiotics, such as griseofulvin, kasugamycin and streptomycin; (e) various fungicides, such as diphenylsulphone, dodine, methoxyl, l-thiocyano-2,4-dinitrobenzene, 1-phenylthio-semicarbazide, thiophanate-methyl and cymoxanil; like acylalanines, such as furalaxyl, cyprofuram, ofurace, benalaxyl and oxadixyl; fluazinam, flumetover, phenylbenzamide derivatives, such as those disclosed in patent EP 578586 Al, amino acid derivatives, such as the valine derivatives disclosed in EP 550788 Al, methoxy acrylates, such as (E) -2- ( 2- (6- (2-Cyanophenoxy) pyrimidin-4-yloxy) phenyl) -3-methoxy-methacrylate methyl; S-methyl ester of benzo (1, 2, 3) thiadiazole-7-carbothioic acid; propamocarb; imazalil; carbendaazim; myclobutanil; fenbuconazole; tridemorph, pyrazophos; fenarimol; fenpiclonil and pyrimethanil. Examples of insecticides that can be combined with the dithiocarbamates of the present invention include, for example, acephate, aldicarb, alpha-cypermethrin, azinphos-methyl, binapacryl, buprofezin, carbaryl, carbofuran, chlorpyrifos, clofentezine, cyhexatin, cypermethrin, deltamethrin, dicofol , diflubenzuron, dimethoate, dinocap, endosulfan, endothion, esfenvaalerate, ethiofencarb, ethion, ethoate-methyl, ethoprop, fenbutatin-oxide, fenoxycarb, denosulfothion, flucycloxuron, flufenoxuron, fosmethilan, hexythiazox, methamidophos, methidathon, methiocarb, methomyl, methyl parathion, mexacarbate, oxamyl, permethrin, phosalone, phosmet, promecarb, pyridaben, Resmethrin, rotenone, tebufenozide, thiodicarb, triazamate and vamidothion. Examples of herbicides that can be combined with the dithiocarbamates of the present invention include, for example: (a) carboxylic acid derivatives, including benzoic acids and their salts; carboxylic acids substituted by phenoxy and phenyl and their salts; glyphosate and its salts, and trichloroacetic acid and its salts; (b) carbamic acid derivatives, including ethyl N, N-di (n-propyl) thiocarbamate and pronamide; (c) substituted ureas, (d) substituted triazines, (e) diphenyl ether derivatives, such as oxyluorfen and fluoroglycofen, (f) anuides, such as propanil, (g) oxyphenoxy herbicides, (h) uracils, (i) nitriles and (j) other organic herbicides, such as dithiopyr and thiazopyr. In the case of herbicides, care must be taken to ensure that the crop to which the composition of the present invention is applied is tolerant of the herbicide. For agrochemical uses, the compositions of the present invention can be applied as powders, granules, powders that can be mixed with water, or aqueous sprays, by commonly employed methods, such as conventional high volume hydraulic sprays, low volume sprays, air and air spray sprays. The dilution and the application regime will depend on the type of equipment used, the method and frequency of the desired application, the application regime of the pesticide and the pests that will be controlled. The formulations, or diluted formulations, of the compositions of this invention may also contain agronomically acceptable adjuvants. These adjuvants include surfactants, dispersants, spreading agents, adhesives and foam, emulsifiers and other similar materials, described in McCutcheon 's Emulsifiers and Detergents, McCutcheon' Emulsifiers and Detergents / Functional Materials, and McCutcheon 's Functional Materials, all published annually by McCutcheon Division of MC Publishing Company (New Jersey). In addition, the compositions of this invention can include one or more agronomically acceptable carriers. The term "agronomically acceptable carrier" means any substance that can be used to assist in the dispersion of the active ingredient of. the composition in water, oil or in the formulation used to control pests, as a powder, without damaging the effectiveness of the active ingredient and which does not have a significant detrimental effect on the soil, equipment, desired plants or the agronomic environment. The compositions of the present invention can also be mixed with fertilizers or fertilizer materials before application. The fertilizer compositions and material can also be mixed in a mixer or combination device or the compositions can be incorporated with fertilizers into granular, powder, water miscible powder or concentrate formulations in solution. Any relative proportion of the fertilizer can be used, which is suitable for the crops to be treated. The compositions of the invention will commonly comprise from 5 to 50% of the fertilization composition. These compositions provide fertilization materials that promote the rapid growth of the desired plants and, at the same time, control the pests. The following examples are illustrative of the invention.

In the following examples, the suspension capacity, exhaustion and efficiency were evaluated, using the following general procedures: Suspensibility Test 2.0 g of the formulation were added to 250 ml of water in a 250 ml graduated cylinder (with obturator). The cylinder was inverted 30 times to disperse the particles and then allowed to stand undisturbed for 30 minutes. The upper 225 ml were then siphoned off and the remaining pellet was washed on a drying disc and dried in an oven. The percentage of suspensibility was calculated by subtracting the sediment weight of 2.0 g, dividing by 2.0 g and then multiplying by 100.

Granule Wear Test 50 g of the dispersible granule formulation were placed in a standard 20.32 cm sieve vessel, with 10 steel balls with 9,525 mm diameter. The container was covered and placed in a Ro-Tap ™ shaker for 10 minutes of agitation. After removing the steel balls, the resulting powder was emptied at the top of a stack of sieves varying from 250 to 45 micron sieve size, with a container in the bottom. The plate was placed on the shaker for 10 minutes of agitation. The weight of the powder retained on each screen was determined and expressed as a percentage of the original sample of 50 g.

Late Tomato Blight Control Test (TLB, Phytophthora infestans) Young tomato plants were sprayed with the dispersed formulation in water, at a rate of approximately 500 grams of active ingredient per hectare. After a drying time of several hours, the plants were subjected to an artificial rain of 1.27 to 2.54 cm. After drying, the plants were inoculated with the TLB disease, incubated and then placed in the greenhouse for 7 to 10 days. The percentage of control of the disease was evaluated visually, estimating the area of the leaf not affected by the disease.

EXAMPLE 1 Mancozeb dispersible granules were prepared by spray drying an aqueous slurry. mancozeb (fungicide Dithane DE®, Rohm and Haas Company) not containing PVA (Sample A), 88% hydrolyzed PVA of molecular weight of 18,000 (Sample B) and 88% of hydrolyzed PVA of average molecular weight of 115,000 (Sample C) ). PVA levels were 0.5% based on the weight of the final product. Table I shows the physical properties of these samples. A good suspensibility was maintained with the PVA (B) of low molecular weight, but it was severely degraded with the PVA (C) of higher molecular weight. Both PVAs improved the soaking time of the granules. For reasons of health and safety, it is convenient to maintain the integrity of the granules under tension and handling in order to minimize the formation of dust. Therefore, the samples were subjected to agitation for 10 minutes with steel balls and they were evaluated in the wear of particles, using the sieve analysis. The ideal granule size for the product is 100 to 250 microns in diameter. Table I shows that sample (B) of low molecular weight has better granule integrity and formed smaller fine particles (ie, granules <100 μ than standard sample (A).) Sample with higher molecular weight PVA had a unacceptable level of large aggregates, which can cause nozzle clogging problems when sprayed.

Table 1 Example 2 Two samples of miscible powder were prepared with 80% mancozeb water by dry mixing a commercial powder that can be mixed with water, (fungicide Dithane M-45®) (Sample A) with 0.5% in weight of hydrolysed PVA at 88% average molecular weight of 18,000, to form Sample B. These samples were then evaluated on the suspensibility, retention in plastic Petri dishes after a rainfall of 2.54 cm (visual estimate) and control of the late blight of tomato (TLB) under humid conditions in the greenhouse. Table II shows the test scores. The formulation containing the low molecular weight PVA (B) had both an increased firmness to rainfall and a control of the disease, compared to the standard formulation, while maintaining good suspension capacity.

Table II EXAMPLE 3 Three 37% Mancozeb suspension concentrates were prepared by mixing a commercial suspension concentrate of mancozeb (fungicide Dithane F-45®, Rohm and Haas Company) (Sample A) with hydrolysed PVA at 88% average molecular weight. 18,000 (Sample B) and hydrolysed PVA at 88% average molecular weight of 115,000 (Sample C). The PVA levels were 0.15% based on the weight of the final product. The samples were mixed with a standard laboratory mixer until all the polymer dissolved. Table III shows the physical properties of these samples. Although the viscosity decreased with the increase in molecular weight of the polymer, the gel strength increased to an unacceptable level (ie,> 100 g-cm) with the increase in molecular weight). Although the firmness to the rain increased with the molecular weight of the PVA (C), the control of the disease of TLB under humid conditions was better for the PVA (B) of low molecular weight. The best control of the disease is probably due to the better redistribution of particles observed for the PVA (B) of low molecular weight. Table III EXAMPLE 4 Three samples of miscible powder were prepared with 80% water by the dry mixture of a commercial powder that can be mixed with water (fungicide Dithane M-22®, Rohm and Haas Company) (Sample A), with 0.5% by weight of hydrolyzed PVA at 88% average molecular weight of 18,000, to form Sample B and 0.5% by weight of hydrolyzed PVA at 88% average molecular weight of 155,000, to form Sample C. These samples then were evaluated in suspensibility and retention on plastic Petri saucers, after 1.27 cm of rain (visual estimate). Table IV shows the results of the tests. The formulation containing the low molecular weight PVA (B) had both increased suspensibility and firmness to rain compared to the sample with the high molecular weight PVA (C). The PVA formulation (B) also has a significantly increased firmness to rain compared to the standard formulation (A), while maintaining a good suspension capacity.

Table IV

Claims (10)

1. CLAIMS 1. A composition "comprising: a) one or more dithiocarbamate fungicides; and b) polyvinyl alcohol, with a molecular weight of 10,000 to 80,000, a hydrolysis level of 77 percent to 95 percent, and a particle size of less than 800 microns. The composition of claim 1, wherein this composition is in the form of a powder mixable with water, a powder formulation, a granular formulation or a suspension concentrate formulation. The composition of claim 1, wherein the dithiocarbamate is in the form of a powder mixable with water, a powder formulation, a granular formulation or a suspension concentrate formulation. 4. The composition of claim 1, wherein the dithiocarbamate is mancozeb, maneb, zineb, ziram, propineb, metiram, thiram, ferbam, metham or dazomet. 5. The composition of claim 1, further comprising an agronomic acceptable carrier. 6. The composition of claim 1, wherein the polyvinyl alcohol has a molecular weight of 10,000 to 50,000. 7. The composition of claim 1, wherein the polyvinyl alcohol has a hydrolysis level of 80 to 90 percent. 8. The composition of claim 1, wherein the polyvinyl alcohol comprises from 0.1 to 2 percent of the total weight of the composition. 9. The composition of claim 1, further comprising one or more insecticides, fungicides, herbicides, or combinations thereof. 10. The composition of claim 1, further comprising a fertilizer.