GB2159057A - Horticultural fungicidal formulations - Google Patents

Abstract

A fungicidal formulation for treating fungal infections of cultivated plants comprises ditalimfos and a pyrimidine of formula <IMAGE> where X is chlorine or fluorine.l

Description

SPECIFICATION Fungicidal Formulations This invention relates to fungicidal formulations and to methods of treating fungal infections of cultivated plants.

The invention provides a fungicidal formulation comprising ditalimfos and a pyrimidine of formula

where Xis chlorine or fluorine.

We have discovered that this combination of ingredients is specially effective in controlling or combatting fungal infections of cultivated plants such as fruit trees such as apples, vines and especially cucurbits such as, for example, melons, marrows, cucumbers and courgettes. These mixtures have been found to give good results against powdery mildew on and especially Erysiphe cichoracearum and Sphaerotheca fuliginea on cucurbits. The compounds of formula (I) are known fungicides described, for example, in British Patent 1 218 623, and their effectiveness is surprisingly improved by the presence of ditalimfos. The latter component is also a known fungicide, being O,O-diethyl phthalimido phosphonothioate with the chemical formula

described, for example, in British Patent 1 034493.

Accordingly the invention also includes a method of treating fungal infections of plants which comprises applying to the plants a fungicidally effective amount of a fungicidal formulation as defined above. The formulation is preferably applied by foliar application at any time before harvest of the crop. The amount and frequency of application will depend on the severity of the fungal disease and the condition of the crop. It has, however, been found that the frequency of treatment needed for fungal control can be reduced by the use of the formulation of the invention, and a valuable reduction in labour cost is achieved thereby.

With regard to the amount of the active ingredients to be employed, it is preferred to apply a foliar spray in which the ditalimfos is applied at a rate of from 20 to 1250 g per hectare, preferably 250 to 1000 g per hectare, and the component of formula (I) at a rate of from 5 to 100 g per hectare, preferably 10 to 50 g per hectare. The ratio of ditalimfos and compounds of formula (I) is preferably from 1:5 to 250:1, for example, from 5:1 to 100:1.

Of the two active compounds comprised by formula (I) above, nuarimol, the compound in which X is fluorine is preferred, though fenarimol (X is chlorine) can equally be used. As noted above both compounds are well known in the fungicide art and can be employed with other compatible fungicides, although generally they are, together with ditalimfos, the sole active ingredients of the formulation.

The fungicide mixtures of the invention are synergistic and, for example, field trials on melons have shown that mixtures applied at a rate of 36 g active ingredient of nuarimol and 750 g active ingredient ditalimfos gave a 96% control of disease (S. fuliginea) whereas the separate components gave a 72% and 81% control respectively. When analysed by the well known "Colby equation" (see Weeds, 15, 20--22 (2967)) this result demonstrates that synergism occurred under the conditions of the field trial.

The formulation of the invention will usually be associated with one or more inert, non-phytotoxic carrier and it is to be understood that the formulation can also include additional fungicide ingredients, though usually it will comprise solely two active ingredients. In orderto simplify manufacture, storage and transport, combinations are normally produced in concentrate form intended for dilution in water to the degree necessary to give the above mentioned application rates. Such concentrated formulations may contain from 0.5 to 90%, preferably from 5% to 90%, by weight of active ingredients associated with an inert non-phytotoxic carrier. Such formulations will usually be in the form of a wettable powder, dispersible granules or a suspension concentrate.

The concentrate formulations are intended for dilution with water or other suitable substances prior to use in conventional spray tanks or for aerial application and it is to be understood that the diluted formulations so produced are formulations in accordance with the invention in which the inert non-phytotoxic carrier is water or other suitable substance.

Wettable powders comprise an intimate mixture of the active ingredients, an inert carrier and an appropriate surfactant. The inert carrier may be chosen from for example alumina, attapulgite clays, montmorillonite clays, diatomaceous earths, precipitated silica, kaoline, micas, talcs and purified silicates.

Effective surfactants can be selected from sulfonated lignins, naphthalene sulfonates and condensed naphthalene sulfonates, alkyl succinates, alkylbenzene sulfonates, alkyl sulfates and nonionic surfactants such as alkyl or aryl initiated ethylene oxide adducts for example ethylene oxide adducts of phenol.

Examples of wettable powders are those having the following composition: Wettable Powders % by Weight Formula I compound 3.0 Ditalimfos 60.0 Surfactants 5.0 Anticaking agent 5.0 Inert carrier to 100.0 Suspension concentrates comprise a suspension of the active ingredients, a surfactant, a suspending agent and water or a non-aqueous medium.Examples of suspension concentrates comprise the active ingredients and for example, surfactants, suspending agent, antifoaming agent, antifreezing agent and water, for example: Suspension Concentrates % by Weight Formula I compound 2.5 Ditalimfos 50.0 Suspending agent 0.5 Surfactants 7.0 Antifoam 0.1 Antifreeze 10.0 Water to 100.0 Examples of dispersible granules are those having the following composition:: Dispersible Granules % by Weight Formula i compound 4.0 Ditalimfos 80.0 Surfactants 10.0 Anticaking agent 2.0 Inertcarrier to 100 The invention also includes a method of preparing the preferred wettable powder formulation comprising as active ingredients ditalimfos and a pyrimidine of formula (I) above, which comprises blending the active ingredients with excipients and milling the blend to give the requisite particle size, preferably being a mean particle size of between 1 and 20 microns.

The pyrimidine of formula (I) in which Xis chlorine is known asfenarimol and is available from Eli Lilly and Company as for example Bloc, Rimidin and Rubigan, and the compound of formula (I) in which Xis fluorine is known as nuarimol, available from the same company as, for example, Trimidal and Triminol.

Ditalimfos is available from The Dow Chemical Company as Dowco 199 or Plondrel.

The following Examples illustrate the invention: EXAMPLE 1 The following wettable powders prepared: % by Weight Fenarimol or nuarimol 3.0 Ditalimfos 60.0 Alkyl naphthalene sulphonate 2.0 Sulphonated kraftsulphonate 3.0 Silicon dioxide 10.0 Kaolin to 100.0 The active ingredients were blended with the specified excipients in conventional mixing equipment.

The blend was then milled in a fluid energy mill to a particle size distribution range of from 0 to 10 microns and finally the mixture was reblended and dearated prior to being packaged.

EXAMPLE 2 The following suspension concentrate was prepared: % by Weight Fenarimol or nuarimol 2.5 Ditalimfos 50.0 Polyaryl ethoxylated phosphate 2.0 Naphthalene formaldehyde condensate 3.0 Ethylene glycol 10.0 Silicone emulsion 0.1 Xanthan gum 0.2 Water to 100.0 The ingredients (with the exception of the suspending agent) were blended with part of the liquid phase and the slurry milled to a fine particle size of 0 to 10 microns.A gel comprising the suspending agent and remainder of the liquid phase was prepared and then mixed with the milled scurry to give the product. EXAMPLE 3 EXAMPLE 3 The following dispersible granule composition was prepared: % by Weight Fenarimol or nuarimol 4.0 Ditalimfos 80.0 Alkyl laurate 2.0 Sodium phenyl sulphonate 8.0 Kaolin to 100.0 The ingredients were mixed and milled in a fluid energy mill to a size range of 0 to 10 microns and granulated.

EXAMPLE 4 The following example illustrates the synergistic properties of the formulations of the invention.

Following intensive use of fenarimol over several years strains af Sphaerotheca fuliginea have developed which are less sensitive to fenarimol. Such strains were used in the following greenhouse experiment.

Cucumber plants at the one true leaf stage and contained in individual pots, were sprayed with aqueous suspension of ditalimfos, fenarimol and ditalimfoslfenarimol mixtures.

24 House after spraying, when the spray had thoroughly dried on the leaf surface, the leaf was inoculated with Sphaerotheca fuliginea. After a lapse of ten days the percentage fungal control was measured in relation to control plants which had not been treated with fungicide components, and the following results were obtained.

Fenarimol (ppm) Ditalimfos (ppm) 0 20 500 0 0 62 95 5 45 88 100

Claims (8)

1. A fungicidal formulation comprising ditalimfos and a pyrimidine of formula

where X is chlorine or fluorine.

2. A fungicidal formulation according to claim 1 in which the ditalimfos and pyrimidine are present in the ratio range offrom 5:1 to 100:1.

3. A fungicidal formulation according to either of claims 1 and 2, in which the pyrimidine fungicide is nuarimol.

4. A fungicidal formulation according to any of the preceding claims in the form of a wettable powder.

5. A fungicidal formulation according to any of the preceding claims in the form of a suspension concentrate.

6. A fungicidal formulation according to any of the preceding claims in the form of dispersible granules.

7. A fungicidal formulation according to any of the preceding claims which comprises ditalimfos and pyrimidine as sole fungicide agents.

8. A method of treating fungal infections of plants which comprises applying to the plants a fungicidally effective amount of a fungicidal formulation as defined in any of claims 1 to 7.