OA11609A

OA11609A - Delivery device for agricultural pesticides.

Info

Publication number: OA11609A
Application number: OA9900287A
Authority: OA
Inventors: Juan Bocanegra; Jorge Cepeda; Glenn C Knudsen
Original assignee: Rhone Poulenc Agrochimie
Priority date: 1997-06-16
Filing date: 1999-12-16
Publication date: 2004-08-12
Also published as: EP0989803A1; PA8453701A1; AU8630698A; WO1998057541A1; BR9810043A; HN1998000097A; ID24517A; SV1998000068A; ZA985185B; PE100899A1; CO4810377A1

Abstract

A device for the controlled and/or altered release of pesticidal substances contained in solid or gel compositions for delivery to a plant comprising an inner water soluble or water dispersible film or bag to contain the composition and an outer protective layer which permits release of the pesticidal substance in use.

Description

1

Delivery Devicc for Agricultural Pesticides (Π 1609

The invention relates to a new delivery device suitable for pesticides,and especially for hazardous pesticides. This is also applicable to eg. plant 5 nutrients and antibiotics.

The legal and environmental requirements are becoming more and moredemanding in relation to the use of pesticides, and the concern for unmanagedresidues of any kind in the working environment. In addition, risk incurred in theenvironment due to emptied containers and broadeast applications is of great 10 concern to regulatory managers worldwide. Even though there are no spécifielaws, it is a natural need to make, use, manipulate and apply the pesticides in thesafest possible way.

The most common ways to apply pesticides are directly to the plant orthe soil or the seed. In ail these situations there are still instances where workers 15 are in some substantial contact with the pesticides.

It has also been described to use pesticides in water soluble bags, but these bags are intended to be dissolved or diluted iri a dilution tank and theresulting solution then sprayed. The manipulation of the pesticides is thusreduced up to the time the diluted spraying mixtures are made, but that does not 20 prevent the contact of the pesticide with the person who sprays the products onthe plants.

An object of the instant invention is to provide a delivery device forpesticides, as well as a cultivation method, whereby contact between thepesticides and the workers is still further reduced, i.e. a cultivation method which . 25 reduces worker exposure to pesticides.

Another object of the instant invention is to provide a direct deliverydevice for pesticides to the plant, as well as a cultivation method, whereby thepesticide is easy to apply to the végétal organism. The advantage of the inventionis to deliver the pesticide, premeasured, so as not to exceed the labeled rate. 30 Another object of the instant invention is to provide a direct delivery device for pesticides to the plant, as well as a cultivation method, which is simpleand cheap, and which requires a very reduced amount of material for theapplication.

It has now been found that these goals may be achieved, totally or 35 partially, by means of the instant invention. ΐ 011609

The présent invention provides a device for the controlled and/or alteredrelease delivery of pesticidal substances, contained in solid or gel compositions,to a plant which device comprises an outer layer of perforated plastics filmhaving eg. several holes generally small in size and an inner water soluble or 5 water dispersible film or bag within the said outer layer. The solid or gelcomposition is such that it need not be diluted before use or application. Thedevice generally contains a pesticidal solid or gel composition.

By controlled and/or altered delivery it is to be understood that thedelivery of the active ingrédient comprised in the composition is made gradually 10 in a time generally extending over a period of time of up to 4 weeks. In practicethe time should generally not exceed four weeks; however this may be moredepending on products or mixtures contained in the device.

For example, a banana plant may be eut, and the device inserted into themother plant. The device will release the active ingrédient into the plant and this 15 will then move into the daughter plant over a period of time. When the activeingrédient does move into the daughter plant it can provide, for example,nematicide/insecticide protection to the plant over the next 180 days as it matures.Furthermore, undesired residues of pesticide in the fruit of the banana plant atharvest may be avoided or reduced. 20 According to another feature, the instant invention provides a device (otherwise named as a container), which container contains one dose of pesticidalcomposition which is not to be diluted before use or application and which isappropriate for, or suitable for, or designed to the treatment of one végétalSystem. The word végétal in the instant spécification, désignâtes a plant or a tree 25 or any intermediate végétal organism such as a bush or the like.

The solidity and/or rigidity of the container, when filled, of the instant invention is generally such that it does not substantially flex under pressure orunder normal conditions. Flexing under pressure is not necessarily important butit must not burst under pressure in normal use before being put into a végétal. 30 The device of the invention may resenxble a Ketchup packet, or a very small pillow. It is generally made from flexible packaging films and filled on amachine used for flexible packaging materials. Thus, the packets are notcompletely rigid. The film is somewhat flexible so there is not the rigidity seenwith eg. condiments that are packaged in foil wrap. 35 According to another feature, the instant invention provides a device 3 011609 having no space between the inner bag or film and the outer layer. Thus, thére isno material such as active ingrédients, adjuvant or carrier or the like in the spacebetween the inner bag or film and the outer layer of plastic film.

According to another feature, the instant invention provides a devicewherein the inner bag or film is adhering to the outer layer.

According to another feature, the instant invention provides a devicewherein the inner bag or film is coated on the outer layer.

According to another feature, the instant invention provides a devicewherein the inner bag or film is applied as an ink would be applied on the insidesurface of the outer layer. The ink-like water soluble or water dispersible materialwill seal off the small holes of the outer layer.

The size of the container may vary in a large range according to the sizeof the végétal to be treated and according to the amount of pesticide which is tobe delivered to the said végétal. Generally the container is smaller than 50 ml,preferably smaller than 20 ml. Typically, containers of the invention are from 1 to6 cm wide and from 4 to 15 cm long. Preferred containers are from 2 cm wideand 4 cm long to 5 cm wide and 15 cm long. More preferred is a container suchas a bag about 4 cm wide and about 7 cm long.

The shape of the container may also vary in relation to the prescribeddose. Generally it may hâve a cvlindrical, or cylinderlike shape in order to be ableto be introduced easily in a soft plant, the section of the cylinder being not limitedto a circle nor to a square or other polygonal form. The term cylindrical shape,indicates the general arrangement of the container, but some narrowing and/orsome broadening of the cross section is possible. It may also be advantageous tohâve at least one extremity of the container having a conic shape. This generalconic shape may hâve itself a round end, or a spike to aid in application to thevégétal. The container may also resemble a Ketchup packet, or a very smallpillow as mentioned above.

The shape of the container is advantageously such that the ratio longersize / smaller transverse size is in the range from 1 or 1.5 to 5, preferably 2 to 4.

The material which constitutes the inner film or bag, may be any water dispersible or, preferably, water soluble polymer, such as PVOH, gelatin, starch, etc.. Polyvinyl alcohol (PVOH) is particularly preferred for its mechanical properties which work well from a handling and machinability view. It is also easily available and has outstanding odour barrier properties. In the future, new 4 011609 films suitable for use in the invention mav also be developed. When it forms abag inside the device, said bag is generally closed by at least one water solubleheat seal. The thickness of the walls of the inner water soluble bag or film may bédetermined to provide appropriate release of the pesticidally active ingrédient in 5 the végétal. A thicker wall provides a slower release. A thinner wall may providea quicker release. This is also useful to influence the amount of pesticide residueremaining in the plant at the harvest time. The thickness is also important toinfluence the rate of solubility of a water soluble material constituting the innerfilm or bag. 10 The water solubi lity is generally such that the material constituting the inner water soluble film or bag may be dissolved at normal températures ofcultivation of plants, that it is to say at température higher than I0°C, preferablyhigher than 15°C. It is not really necessary that the dissolving takes place rapidlyin the plant. A lengthy dissolution due to a low solubility may be very convenient 15 as providing a slower release of the pesticidal compound.

The plastics film constituting the outer layer of the device according to the invention comprises at least one polymeric material, including polymers andcopolymers and is preferably water insoluble and optionally biodégradable. Apreferred polymer is polyethylene terephthlate (PET). The size and number of 2C small holes is determined according to the desired delivery or release time.Preferably, the size of each small hole is from 0.025 to 0.125 cm (0.01 to 0.05inches) and the number of small holes is at least 1 hole and no more than 25 persquare cm of the plastics film surface. More holes can be used, for example upto 150, eg up to about 100. Holes are not necessarilÿ identical as far as diameters 25 are concerned. The aim of the outer plastics film is also to prevent the inner filmor bag being dissolved, for instance by the user, and to prevent individual packetsfrom sticking together for example during storage..

Alternatively, the plastic film may be replaced by a degradable material,eg paper, su«.h as tcabag paper, made generally from a type ofbanana tree pulp, 30 which thertfore uhUfre very degradable in for instance a banana plant. In thiscase, it would not. require any holes. If desired holes could, of course be formed,eg stamped, in it.

The inner bag may be also such that it is separated by an additionalplastics sheet (either PVOH or PET or, in general, a water insoluble, water 35 dispersible or water soluble material) thus leading to an inner bag having two 5 011609 compartiments each of which having one different pesticide inside. The indîvidualpacket will therefore hâve a two cell unit that could hold two products. Forexample one part of the bag may contain a fungicide (such as fosetyl-AI) and thêother part an insecticide (such as aldicarb). The advantages are obvious : less 5 packaging material used, easier application (one device instead of two), lessexpensive to use in the method of the invention.

The pesticidally active formulation which is contained in the containermay be a solid or a gel. However, solid formulations are preferred because theyare more favourable in reducing the risk of exposure of the people who are io handling or manufacturing the said compositions or formulations. Still morepréférable are the substantially dustless formulations, for example those whoseparticle size is more than 0.1 mm, preferably from 0.4 to 8 mm.

The pesticidally active formulation which is contained in the device ofthe invention is preferably concentrated. The more concentrated the formulation 15 the smaller the water soluble container can be and the less damage made to thevégétal when the containerisation device of the invention is introduced therein.

Pure pesticidally active ingrédient may be used and enclosed in the device, but, itis often desired to hâve the said active ingrédient or pesticide incorporated in anappropriate formulation which may help the dissolving inside the végétal, and/or 20 the spreading of the said ingrédient in the whole végétal. It may also be désirableto hâve a formulation which itself Controls the release of the active ingrédient inthe végétal. Concentrations higher than 15 % (w/w) are thus generally used.Preferably the concentrations of these formulations are even higher than 20 % oreven better, higher than 40 %. However, the main criterion is the water solubility 25 of the pesticide rather than the concentration of the pesticide. In the case ofbanana treatment for instance, the release would not be intentionally delayedbecause there is only a short period of time before the mother plant will begin todie and as it dies, the ability to transfer the pesticide, as desired to the daughterplant will decrease. Fast release and transfer is desired. A phytotoxic response at 30 this time is not a great concem since the mother plant has already been harvestedand the release of the pesticide to the daughter plant will be somewhat graduai.

According to another feature, the instant invention provides a deliverydevice as already defined which contains one or more pesticides which arenaturally toxic at low dose for mammals, and/or which are at least partially 35 soluble in water. 011609

According to another feature, the instant invention provides a deliverydevice wherein the active ingrédient, or pesticidal substance, of the solid or gelcomposition is systemic. By systemic, is meant that the active ingrédient is ableto use the natural flow of material in the plant in order to move inside said plant. 5 Preferably, the active ingrédient is aldicarb. More advantageously, thecomposition is a composition comprising aldicarb and gypsum. Preferably,aldicarb is adsorbed on gypsum. However, other aldicarb formulations aresuitable, such as aldicarb adsorbed on corn cob grits.

The invention provides a method of treating a plant with a pesticideto which method comprises inserting into a plant a device according to the invention. The device may, for example, be inserted into a hole eut or bored intothe plant.

According to another feature, the instant invention provides a method forvégétai cultivation, in which the said végétal contains a soft part and at least one 15 device as defined above is inserted into the végétal by pressure and/or in a holepreviously made in, eg bored or eut in the végétal, eg the mother trunk in the caseof a banana.

In this cultivation method, the inner film or bag of the device issufficiently dissolved so as to release the pesticide included therein directly inside 20 the végétal. The végétal is soft enough so as to make possible the introduction ofthe said container inside the said végétal without a substantial damage to the saidplant.

The method of the instant invention is especially suitable for banana orplantain trees, especially banana or plantain trees which hâve been eut after 25 harvesting. The place of cutting is generally rather soft and well suited to theintroduction of a delivery device therein. The introduction of the delivery deviceinside a banana plant then protects the next génération of plant which grows fromthe bottom of the said eut mother plant. Other plants or trees may of c< arse betreated, eg date palms. Due to tht controlled Cclease which can be obuined by 30 variation of different characterislîcs of the centainer as indicaftd here aboie, it ispossible to hâve a variable release rate in the frt«- from very slow to a fajjîdrelease of product. Also, the method may involve more than one device per plant.Each device may be at separate locations in the plant, eg in bored or eut holes.Alternatively, for the method for treating banana or plantain plants one or more 35 device as described above may be inserted by pressure and/or in a hole previously 01 1 60-9 bored in the daughter trunk of a plant. This is particularlv suitable when pesticides either hâve a short half life and/or require a limited preharvest interval.

The pesticide of the instant invention may be for example a herbicide, a' fungicide, a nematocide, a bactéricide, an antibiotic, a plant growth regulator or 5 plant nutrient or an insecticide or combination thereof. The invention is especiallyadvantageous for pesticides having high acute or chronic toxicity for mammals atcertain rates and in certain conditions. The invention is especially of interest forinsecticides / nematocides.

Pesticides which are well suited for use in the invention hâve some water 10 solubility and systemic activity so as to be able to move inside the végétal.

Among the many pesticides which can be used, examples include methylcarbamates, such as aldicarb ; the l-arylpyrazoles such as fipronil ; imidacloprid ;fosetyl-Al ; carbofuran ; benomyl ; terbufos ; oxamyl ; fosthiazate ; these activeingrédients being well known to persons skilled in the art. 15 One of the advantages of the device and method of the invention is illustrated by its use to deliver aldicarb to bananas: it minimizes the residue ofaldicarb in the banana plant and contamination of the surrounding soil (more than99% of the active ingrédient goes into the plant and substantially no aldicarb goesinto the soil). Therefore îess material is needed and the speed of absorption by the 20 plant is greatly accelerated. The aldicarb flows from a mother plant to a daughterplant without being applied to the soil or to the daughter plant directly. Thislimits the contamination of the soil by aldicarb and provides thus a safe and novelmethod of applying aldicarb to the new plant. It may be that a minimal amount ofaldicarb may leave the plant through root exudates. 25 Substantially no pesticide is expected to be released into the soil.

However, depending on the nature of the active ingrédient, there is a possibilitythat as the pesticide may move from mother to daughter plant and into the rootSystem. A highly water soluble pesticide might partition into the soil if there wasa very high concentration of water in the soil (for example during heavy rain). 30

Example :

About 0.8 grams of aldicarb (as Temik ™ GG 15 % w/w on gypsumgranules) were placed in a packet that is approximately 8 cm long by 3 cm wide 35 and 1.5 cm thick. This packet was made of water soluble polyvinyl alcohol. 01160..9

The packet was filled and then sealed using a high température seaFer.This water soluble packet was itself put in a second packet made of a plastic filmwith several small size (about 0.075 cm (0.03 inches)) holes. The outer plastic "packet is a little larger than the inner polyvinyl alcohol packet so as to enclose it 5 without further substantial freedom of movement.

The packet was placed into a freshly eut banana plant and left for about aweek, after which time the granules were recovered. The percentage of aldicarbleft on the granules was less than 2% by weight.

Claims

1. A device for the controlled and/or altered release of pesticidal 5 substances contained in solid or gel compositions for delivery to a plantcomprising an inner water soluble or water dispersible film or bag to containthe composition and an outer protective layer which permits releasegradually in small doses of the pesticidal substance in use. io

2. A device according to claim 1 for the controlled and/or altered release delivery of pesticidal substances contained in solid or gelcompositions to a plant comprising an outer layer of perforated plastics filmand an inner water soluble or water dispersible film or bag within the saidouter layer. 15

3. A device according to claim 1 or 2 having no space betweenthe inner bag or film and the outer layer.

4. A device according to claim 3 wherein the inner . bag or film 20 adhères to the outer layer.

5. A device according to claim 4 wherein the inner bag or film iscoated on the outer layer. 25

6. A device according to claim 5 wherein the inner bag or film is applied like an ink on the inside surface of the outer layer.

7. A device according to any of one of the preceding claimshaving a cylinder shape or a pillow shape. 30

8. A device according to claim 7 wherein the cylinder has a roundor polygonal base at one end and a spike shape at the other end.

9. A device according to any one of the preceding claims wherein 35 the inner film forms a bag and has at least one water soluble heat seal. 10 011609

9 011609 Claims:

10. A device according to any one of the preceding daims whereinthe inner bag or film comprises polyvinylalcohol (PVOH). 5

11. A device according to any one of the preceding daims wherein the outer layer, optionally biodégradable, is preferably PET.

12. A device according to any one of the preceding daims whereinthe outer layer has perforations and the perforations are holes from 0.025 to îo 0.125 cm (0.01 to 0.05 inches) in size and the number of small holes is atleast 1 hole and no more than 25 per square cm of the outer layer surface.

13. A device according to any one of the preceding claims whereinthe active pesticidal ingrédient of the solid or gel composition is systemic.

14. A device according to any one of the preceding claims whereinthe active pesticidal ingrédient is aldicarb.

15. A device according to any one of the preceding claims wherein 20 the composition comprises aldicarb and gypsum.

16. A device according to claim 15 wherein the aldicarb isadsorbed on gypsum. 25

17. A method of treating a végétal with a pesticide which method comprises inserting into the végétal a device according to any one of thepreceding claims.

18. A method according to claim 17 for treating banana or plantain 30 plants wherein at least one device according to any one of the preceding claims is inserted by pressure and/or in a hole in the mother trunk of theplant.

19. A method according to claim 18 wherein the device is inserted 35 inside the mother trunk once its fruits are harvested and its head is eut. II 011609

20. A metbod according to claim 18 or 17 using more than onedevice per végétal or plant, each device being in a separate hole.

21. A method according to claim 17 fortreating banana or plantainplants wherein at least one device according to any one of daims 1 to 16 isinserted by pressure and/or in a hole in the daughter trunk of the plant.

22. A method according to claim 21 in which the pesticide eitherhas a short half life and/or requires limited preharvest interval.

23. A method according to claim 17 in which the végétal is a date palm.

24. A device according to any one of daims 1 to 10 wherein theouter layer comprises plastics film, and the inner bag or film comprisespolyvinylalcohol (PVOH) and adhères to the outer layer.

25. A device for the controlled and/or altered release of pesticidalsubstances contained in solid or gel compositions for delivery to a plantcomprising an inner water soluble or water dispersible film or bag ofpolyvinylalcohol (PVOH) to contain the composition and an outer protectivelayer of paper which permits release gradually in small doses of thepesticidal substance in use.

26. A device according to claim 25 for the controlled and/or alteredrelease delivery of pesticidal substances contained in solid or gelcompositions to a plant wherein the outer layer is perforated and an innerwater soluble or water dispersible film or bag is within the said outer layer.

27. A device according to claim 25 or 26 having no space betweenthe inner bag or film and the outer layer.

28. A device according to claim 27 wherein the inner bag or filmadhères to the outer layer. 12 011609

29. A device according to claim 28 wherein the inner bag or film is coated on the outer layer. 5

30. A device according to claim 29 wherein the inner bag or film is applied like an ink on the inside surface of the outer layer.

31. A device according to any one of daims 25 to 30 having acylinder shape or a pillow shape. 10

32. A device according to claim 31 wherein the cylinder has around or polygonal base at one end and a spike shape at the other end.

33. A device according to any one of daims 25 to 32 wherein the15 inner film forms a bag and has at least one water soluble heat seal.

34. A device according to any one of daims 25 to 33 wherein theouter paper layer has perforations and the perforations are holes from 0.025to 0.125 cm (0.01 to 0.05 inches) in size and the number of small holes is at 20 least 1 hole and no more than 25 per square cm of the paper surface.

35. A device according to any one of daims 25 to 34 wherein theactive pesticidal ingrédient of the solid or gel composition is systemic. 25

36. A device according to any one of daims 25 to 35 wherein the active pesticidal ingrédient is aldicarb,

37. A device according to any one of daims 25 to 36 wherein thecomposition comprises aldicarb and gypsum. 30

38. A device according to claim 37 wherein the aldicarb isadsorbed on gypsum. 35 13 011609

39. A method of treating a végétal with a pesticide which methodcomprises inserting into the végétal a device according to any one of daims 5 25 to 39.

40. A method according to claim 39 for treating banana or plantainplants wherein at least one device according to any one of daims 25 to 38 isinserted by pressure and/or in a hole in the mother trunk of the plant. 10

41. A method according to daim 40 wherein the device is insertedinside the mother trunk once its fruits are harvested and its head is eut.

42. A method according to claim 39 or 40 using more than one15 device per végétal or plant, each device being in a separate hole.

43. A method according to claim 39 for treating banana or plantainplants wherein at least one device according to any one of daims 25 to 38 isinserted by pressure and/or in a hole in the daughter trunk of the plant. 20

44. A method according to claim 43 in which the pesticide eitherhas a short half life and/or requires limited preharvest interval.

45. A method according to claim 39 in which the végétal is a date 25 palm.