IL29358A - Anhydrous pesticidal aerial spray compositions and the use thereof in controlling noxious organisms - Google Patents

Description

thereof ia controlling noxious organisms The invention relates to pesticides which can be sprayed and are suitable inter alia for use in aerial crop The term pesticides is to be understood to mean herein compositions which are used in controlling noxious organisms in agriculture and for insecticidal and fungicidal The spray technologies developed in the last few years have rendered it possible to evenly deposit small quantities of a liquid pesticide from an aircraft or copter on comparatively large in order to obtain a good coverage of the crop to be treated with these sprays from an it is necessary to deposit the composition on the crop in very fine A good degree of coverage is obtained when liquid deposited on the crop consists for at least 80 ticles having a diameter of from to Various for physical ties of the spray spray nozzle type of the spraying apparatus and climatological have an important influence on the droplet size characteristic of a sprayed It has been endeavoured to eliminate the very fine particles from the droplet spectrum by a change of 2224 the physical properties of the and notably an increase of the and thus to obtain a rower droplet Particles having a small diameter have a proportionally slow descent Stokes1 and may easily be drifted away by forces acting ly on the direction of descent as a result of which not only the quantity of the composition deposited on the crop is smaller but also surrounding fields may be with the In addition special spray nozzles adapted to the physical properties of the spray have been tured to realize a satisfactory deposit of a composition from It is known to increase the viscosity of liquid pesticides by adding hi molecular for hydroxyethyl to the composition to be In spraying such a more viscous composition the droplet spectrum moves towards the larger droplet diameter so that the descent of the drops is more Drops of a more viscous liquid disintegrate moreover less readily to smaller in particular when the liquid has In order to obtain a finely divided composition on the it is course not sufficient that the sprayed composition initially has a favourable droplet it should also be ensured that the droplet racteristic of a sprayed composition does not or 2224 tially not vary during Especially in those districts where a high perature of the open air is associated with a low relative humidity of the strong evaporation of volatile for from the sprayed particles will so that the droplet spectrum moves towards a which consequently result particle size and again drift loss of composition io rooulte It has been proposed to add substances for nol and methyldibutylamine to the pesticides tined for spraying so as to check in this manner the poration of water from the sprayed particles Since a ficiently rapid coverage of the surface of with a film of an substance is very hard to realize in air turbulences inhibit the spreading of the substance over the whole surface of the spray the effect often is Also the addition of thickeners to pesticides results in a decrease of the evaporation of volatile constituents from the spray particles since the free mobility of the molecules to the surface of a spray droplet is somewhat The evaporation is minimum when the compositions to be sprayed consist of or sparingly tile constituents for a dispersion of a solid active substance in a mineral 2224 The which contain ing agents if required9 stances for aerial spraying have the drawback that the availability of the active constituents and hence the logical activity of the composition may be strongly The thickeners encapsulate the active constituents and also hamper the spreading of the spray droplets on the As a result of the slow evaporation of the volatile constituents from a spray droplet deposited on the the rigidity of the droplet and the extent of tion will increase In pesticides also which contain no thickeners but in which a solid active substance is persed in a viscous mineral the the active substance from the oil phase is inhibited and the biological activity of such a composition consequently will be smaller than may be expected on the basis of the biocidal power of the active substance Precisely in volume aircraft crop spraying it is of importance that the biological activity of the active constituents is used as readily as Applicants have found that anhydrous pesticides can be composed which are extremely suitable for aircraft crop spraying and in which a coverage of the crop with the sprayed particles of composition is obtained and in addition the availability of the active constituents from the sprayed particles is particularly favourable Anhydrous compositions are to be understood to PEN 2224 mean herein compositions are anhydrous and may contain up to approximately 5 weight of The composition according to the invention is characterized in that the active substance is dissolved in a fatty oil or a derivative of a fatty oil and the solution has a viscosity of 5 50 cP As active stances which are used in compositions according to the invention may be mentioned by way of examples liquid ganic phosphorus for sumithion and in addition 5 sulphide designated herein for short as tetrasulJ esters of 2 acetic acid and 2 acetic acid with sparingly volatile for and propanol and esters of 2 acetic acid and 2 4 acetic acid with volatile for propanol and ethanole In a preferred embodiment of the composition according to the invention DDT and esters of 2 dichlorophenoxy acetic acid with both volatile and volatile alcohols are used as the active As fatty oils may be by way of stor oil and rapeseed oil but preferably the composition cording to the invention contains It has so been found that turkey red a sulphonated is very suitable for use in compositions according to the in additional advantage is obtained that the spray droplets can be redistributed on 2224 the crop moisture so that a better coverage is The invention also relates to pesticidal sitions which in addition to the active substance and the fatty an auxiliar solvent which increases the solubility of the active substance in the In ticular in compositions which contain an active substance which is solid at normal pressure and for tetradifon and an liary solvent must also be presente Auxiliary solvents which are used are inter for acetyl acetone and for methyl for tetrahydrof rane and dibutyl aromatic for xylenes and naphthenes and aliphatic In a favourable embodiment of the composition according to the invention the auxiliary vent in the composition is By varying the volume ratios of the fatty the active and the auxiliary solvent in the composition according to the a viscosity can be adjusted which is desirable for aircraft applications and which is suitable for the spray nozzles which contain an active substance which is thinly liquid at normal pressure and temperatures will generally have a comparatively high content of the fatty oil whereas in compositions which contain an active substance which is more viscous at normal pressure and the volume percentage of fatty oil 1B The viscosity of an auxiliary solvent possibly present in the composition will also influence the volume percentage of the fatty In a favourable embodiment of a composition according to the the composition contains from 20 to by volume of castor She invention also relates to a method of controlling noxious organisms by spraying an anhydrous pesticide in a quantity of from to 25 per hectare on the area to be and is characterized in that a pesticide according to the invention is sprayed by means of a spray system suitable for that preferably of the sprayed particles having a diameter of from to 150 The availability of the active substance from the pesticide according to the invention The surface of the spray droplets is densely covered with the molecules of the active substance while the mobility of the active substance molecules in the solution according to the invention is so large that open places at the surface of a liquid caused by consumption of molecules of the active substance at the surface of the droplet by noxious will quickly be filled up with molecules of the active composition according to the invention may be prepared in a simple manner by mixing a pesticidal compound which can be mixed with a fatty for malthion and which is liquid at 2224 mal pressure and with the fatty for castor whilst if while heatingo a solid pesticidal compound which does not dissolve in a fatty for tetrasul and carbaryl may be dissolved in an organic for castor and then a fatty for may be mixed with the cyclohexanone solution whilst stirringc In order that the invention may readily be carried into one example thereof will now be described in deta l Example kgms of tetradifon are dissolved in kgms of cyclohexanone in a mixing vessel at room temperature whilst stirring castor kgms of oil are added to the solution after whioh the resulting mixture by filtration nts from solid if an The resulting pesticidal solution according to the invention may be sprayed directly without further ment from an airoraft whioh comprises a spraying apparatus suitable for volume spraying over the area to be treated in a dose of 5 of composition per hectare insufficientOCRQuality

Claims (20)

1. Anhydrous ae herein defined, pesticidal compositions for aerial spraying, characterized in that ■fheyconsist*, of a solution of the active substance in a fatty oil or a derivative of a fatty oil and the solution has a viscosity of 5 to 50 cP.

2. * Pesticidal compositions as claimed in Claim 1, wherein the fatty oil is castor oil or a sulphonated castor oil*

3. Pesticidal compositions as claimed in Claim 1 or 2, wheroin the composition contains malathion as the active substance.

4. Pesticidal compositions as claimed in Claim 1 or 2, wherein the composition contains an auxiliary solvent which increases the solubility of the active substance in the oil.

5. Pesticidal compositions as claimed in Claim 4, wherein the auxiliary solvent is cyclohexanone.

6. Pesticidal compositions as claimed in Claim 5*. wherein the composition consists of tetradifon, cyclohexanone and castor oil.

7. Pesticidal compositions as claimed in any of the preceding claims* wherein the oil content is from 20 to 8CfS by volume of the total volume of the composition*

8. Pesticidal spray compositions according to Claim 1, substantially as herein described with reference to the specific example. 29358/2

9. A method of preparing a pesticidal composition as claimed in any of Claims 1 to 8, wherein a pesticidal compound is dissolved in a fatty oil or a derivative of a fatty oil, the resulting solution having a viscosity of 5 to 50 cP.

10. A method as claimed in Claim 9, wherein the pesticidal compound is dissolved in castor oil or a sulfonated castor oil*

11. A method as claimed in Claim 9» wherein oalathion is dissolved in castor oil.

12. A method as claimed in Claim 9» wherein the active compound is dissolved in an auxiliary solvent, e.g. eyclohexanone and the resulting solution is then mixed with a fatty oil.

13. A method as claimed in Claim 12, wherein tetradifon is dissolved in cyclohexanone and the resulting solution is mixed with castor oil.

14. A method of preparing pesticidal compositions as claimed in any of Claims 1 to 3, substantially as herein described wi reference to the specific example.

15. A method of controlling noxious organisms by spraying an anhydrous pesticide in a quantity of from 0.5 to 25 Itrs. per hectare on the area to be treated, wherein a composition as claimed in any of Claims 1 to 8 is sprayed by means of a spraying system suitable for that purpose, in which preferably at least 80 of the sprayed particles have a diameter of 50 to 100 microns.

16. A method as claimed in Claim 15, wherein a solution of a pesticidal compound in a fatty oil is sprayed. 29358/2

17. A method as claimed in Claim 15, wherein a solution of malathion in castor oil or a sulphonated castor oil is sprayed.

18. A method as claimed in Claim 15, wherein a solution which consists of a pes icidal conpound, an auxiliary solvent, and a fatty oil is sprayed,

19. A method as claimed in Claim 18, wherein a solution which consists of a pesticidal compound, cyclo-hexanone, and a fatty oil is sprayed.

20. A method as claimed in Claim 19, wherein a solution which consists of tetradifon, cyclohexanone and castor oil is sprayed. PCiCB