GB2101487A - Fungicidal spray - Google Patents

Abstract

A preparation for use as a fungicidal spray comprises a water-in- oil emulsion having an aqueous phase containing a suspended fungicidal powder and an oil phase the composition also containing a surfactant suitable to maintain the emulsion in a stable condition.

Description

SPECIFICATION Fungicidal spray The present invention reiates to fungicidal preparations and more particularly to fungicidal preparations which may be packaged in an aerosol form.

It is known that certain compounds have fungicidal properties and may be used, inter alia, for the treatment of fungus diseases and plants. These fungicidal compounds are generally applied as a dust, as an aqueous suspension of a wettable powder, or as emulsions of organic solutions in water. The present invention provides a novel form of fungicidal preparations in which an oil-in-water emulsion is provided which has a powder fungicide suspended in the aqueous phase.

Aerosol packaged fungicides are known which use fungicides which are soluble in organic solvents. This limitation has severely restricted the groups of fungicides which may be included in aerosol fungicidal preparations. The fungicidal preparation according to the present invention allows a considerably wider range of fungicides to be used in aerosol formulations, allows water to form part of the carrier in such formulations, and avoids the problem of aerosol can corrosion in water based systems by having the water present as a water-in-oil emulsion.

The present invention consists in a fungicidal preparation which comprises a water-in-oil emulsion having an aqueous phase containing a suspended fungicidal powder and an oil phase, the composition containing a surfactant suitable to maintain the emulsion in a stable condition.

In a preferred form of the invention adapted for use in aerosol formulations the oil phase also contains an aerosol propellant. This propellant may be a hydrocarbon, a halogenated hydrocarbon, a mixture thereof or any other conventional aerosol propellant.

The fungicidal powder is preferably of a type which shows prolonged stability in the presence of water. If, however, the aerosol spray is to be used quickly then the degree of long term stability is less important. Particularly preferred are fungicidal powders containing as an active ingredient chlorothalonil which is the ISO standard name for Tetrachloroisophthalonitrile. Powders such as those sold by Diamond Shamrock Corp. under the Registered Trade Marks "BRAVO W-75" and "DACONIL" are most preferred. These preparations contain about 75% by weight of chlorothalonil together with suitable surfactants to render the powder wettable. A combination of two or more fungicidal powders may be present in the preparation.

It is preferred that the fungicidal powder or powders be present in an amount of from 0.01 to 1% by weight, more preferably from 0.05 to 0.5% by weight of the total preparation.

The preparation according to this invention also preferably includes a fungicide or fungicides dissolved in the aqueous phase or the oil phase of the emulsion. Preferred fungicides for dissolution in the oil phase include dimethirimol and fenarimol.

The preparation may also include incidental components such as anti-oxidants, bacteriocides, oils and like substances designed to produce leaf shine, insecticides, nutrient salt compositions, perfumes and the like.

The oil phase preferably comprises an organic liquid which is not deleterious to plants. The preferred organic liquids are isododecane and petroleum fractions with low aromatic levels sold under the trade marks Shellsol T, Isopar G and Isopar H (Shellsol and Isopar are registered trade marks).

The propellant is preferably present in an amount of from 35 to 45% of the total composition and the oil phase including the propellant preferably amounts to from 45 to 70% of the total composition. In particularly preferred embodiments of the invention the propellant level is 40% by weight of the total composition. If the propellant level is increased too high the spray produced by the composition is flammable whereas if the propellant proportion is allowed to drop too low inferior spray patterns are achieved.

Any suitable surfactant which has a capacity to maintain the stability of water-in-oil emulsions may be used. The amount of surfactant required will vary with the effectiveness of the surfactant, however, in general amounts of from 0.1 to 5% have been found adequate. Surfactants are most preferably present in an amount from 0.25 to 1% by weight of the composition. A particularly preferred surfactant is a polyglycerol oleate sold as Witconol 14 (Witconol is a registered trade mark) however, other similar surfactants could be used.

The compositions according to the present invention are preferably packed in lacquered cans and are dispensed through known valves which are used for water based compositions and which include a vapour tap.

The present composition has been found to have the advantage that can corrosion from the water content of the fungicide is substantially reduced by the use of a water-in-oil emulsion.

It has also been found that in aerosol formulations according to this invention low doses of known fungicides are showing greater activity than is normally found. It is believed this may be due to the fine particle size of droplets produced from aerosol containers.

Hereinafter described by waybf example only are preferred embodiments of the present invention.

EXAMPLE 1 Weight Proportion Name %W/W Bravo W-75 Fungicide 0.150 Butylated Hydroxytoluene 0.005 Witconol 14 0.500 Isododecane 12.000 Deionized Water 47.345 Hydrocarbon Propellant 40.000 Bravo W-75 (Registered Trade Mark) fungicide contains chlorothalonil (ISO standard name) which is tetrachloroisophalonitrile as active ingredient.

EXAMPLE 2 Weight Proportion Name %W/W Bravo W-75 Fungicide 0.1 50 Milcurb Fungicide 0.200 Witconol 1 4 0.500 Butylated Hydroxytoluene 0.005 Isododecane 11.145 Deionized Water 48.000 Hydrocarbon Propellant 40.000 Milcurb (Registered Trade Mark) fungicide contains Dimethirimol (ISO standard name) which is 5-Butyl-2-dimethylamino-6-methyl pyrimidin-4-ol as active ingredient.

EXAMPLE 3 Weight Proportion Name %W/W Bravo W-75 Fungicide 0.150 Rubigan Fungicide 0.020 Witconol 14 0.500 Butylated Hydroxytoluene 0.005 Isododecane 11.325 Deionized Water 48.000 Hydrocarbon Propellant 40.000 Rubigan (Registered Trade Mark) fungicide contains Fenarimol (BSI standard name) which is 2,4'-dichloro-a-(Pyrimidin-5-yl)-benzhydryl alcohol as active ingredient.

The aerosol formulation (Example 1) when applied as a thin film provided control of Celery Leaf Spot, Downy Mildew of lettuce and Target Spot of tomato equal to high volume aqueous based sprays of Bravo W-75 fungicide at 1 50 g product per 100 litres.

Both treatments contained 1.13 g active ingredient per kilogram of spray. Control was equal despite the fact that considerably less weight of spray was applied to the plants by aerosol than was applied by normal spray.

An example of these results follows for Celery Leaf Spot.

RESULTS OF CELERY TRIAL First Rating No. of Second Rating Infected Leaflets per % Leaf 10 Leaves % Leaves Area Crop Vigour Treatment per Plot Infected Infected Rating Fungicide Aerosol 0.5 32.5 1.1 9.9 (Example 1) Bravo W-75 aqueous 1.0 5.0 0.1 9.6 Spray 150 g/100 L Untreated Control 18.3 97.5 22.8 7.0 The first rating of the number of infected leaflets per 1 0 leaves per plot was taken after the plants had been treated weekly for four weeks. After a further two treatments the second rating was taken of % leaves infected, 5 leaf area infected and a crop vigour rating.

The results show equivalent control by both treatments which are both superior to the untreated control.

Claims (11)

1. A fungicidal preparation which comprises a water-in-oil emulsion having an aqueous phase containing a suspended fungicidal powder, and an oil phase, the composition containing a surfactant suitable to maintain the emulsion in a stable condition.

2. A fungicidal preparation as claimed in Claim 1 in which the oil phase contains an aerosol propellant.

3. A fungicidal preparation as claimed in Claim 1 or Claim 2 in which the fungicidal powder contains as active ingredient chlorothalonil.

4. A fungicidal preparation as claimed in any one of Claims 1 to 3 in which the fungicidal powder is present in an amount of from 0.01 to 1% by weight of the preparation.

5. A fungicidal preparation as claimed in any one of Claims 1 to 4 in which the preparation contains at least one additional fungicide dissolved in the aqueous phase or the oil phase of the formulation.

6. A fungicidal preparation as claimed in any one of Claims 1 to 5 in which the oil phase contains isododecane or petroleum fractions with low aromatic levels.

7. A fungicidal preparation as claimed in Claim 2 or in any claim dependent thereon in which the propellant comprises from 35 to 45% by weight of the preparation.

8. A fungicidal preparation as claimed in any one of Claims 1 to 7 in which the oil phase of the emulsion comprises from 45 to 75% by weight of the preparation.

9. A fungicidal preparation as claimed in any one of Claims 1 to 8 which the surfactant is a polyglycerol oleate.

10. A fungicidal preparation as claimed in any one of Claims 1 to 9 in which the surfactant is present in an amount of from 0.1 to 5% by weight of the preparation.

11. A fungicidal preparation substantially as hereinbefore described with reference to any one of Examples 1 to 3.