WO2004035131A2

WO2004035131A2 - Method and cover for protecting crops

Info

Publication number: WO2004035131A2
Application number: PCT/IL2003/000842
Authority: WO
Inventors: Avner Barazani
Original assignee: Makhteshim Chemical Works Ltd.
Priority date: 2002-10-18
Filing date: 2003-10-16
Publication date: 2004-04-29
Also published as: AU2003274638A8; IL152367A0; AU2003274638A1; WO2004035131A3; PA8586701A1; AR041665A1

Abstract

A polymeric protective cover for controlling fungi diseases in crops which is impregnated with at least one fungicide and optionally additional fungicides or insecticides. A futher aspect of the invention is a method for preharvest and/or postharvest protection of crops. Another aspect of the invention is a polymeric composition comprising a polymer and a fungicide which is suitable for the preparation of a protective cover.

Description

Method and Cover for Protecting Crops

Field of the Invention

The present invention relates to the field of pest control in crops. Particularly, the present invention relates to a method and a cover for protecting crops.

Background of the Invention

There are known methods and covers for protecting crops from pests such as insects, wherein said covering is a plastic bag of polymeric material which is wrapped around the crop in need of protection. This method is predominantly employed in the cultivation of bananas and plantains. Such a bag impregnated with an insecticide chlorpyrifos is sold by Makhteshim-Agan Industries Ltd. under the name Pyritilene®. Said bag provides improved protection to the crop by creating an atmosphere of chlorpyrifos vapor in the bag and around the crop, hence exterminating insects on the crop and in the vicinity thereof. Said coverings additionally protect the crop against mechanical damage which may result for example from strong winds and leaves of the tree brushing against the crop. The covering further provides protection against ultra violet radiation and further elemental hazards such as extreme weather conditions including strong winds and hail.

WO 02/35930 in the name of the present applicant, discloses a sheet for pest control, which is constructed of multi-layers and contains at least an herbicide. Said sheet cannot be used in accordance to the present invention due to the herbicidal content of said sheet.

The addition of active compounds to plastics in order to provide protection to the plastic is known in the art. U.S. Patent No. 5,326,777 discloses a method of protecting plastics from fungi by the blending of a synergistic mixture of tebuconazole and carbendazim with the starting materials required for polymerization. However, said method is intended for protecting plastic and does not provide for protection of crop.

U.S. Patent No. 4,888,175 discloses a package made of a plastic sheet having a biocidal agent, 10,10-oxybisphenoxarasine, dissolved or dispersed within the sheet so that the biocidal agent inhibits bacterial or viral activity in the soil and root structure which is wrapped by said plastic. However, said sheet is not suitable for protecting crops against fungal attack and insects.

The prior art provides an effective method and cover for protecting crops against insects. However, when the crop in need of protection is wrapped in the protective covering it is not protected from fungal attack which may occur and damage the crop. Methods for protecting crops against fungal attack include dusting or spraying the crop with effective fungicides. However, dusting or spraying the crop when it is protected with a cover such as a bag would require the removal of the cover prior to the application and then covering the crop after application. To treat the crop accordingly would be cumbersome and not practical. Thus said treatment is not practiced. The damages from various fungal pathogens to crops which are covered with a protective cover cause a reduction in yield which results in financial damage. There are fungicides which are effective against said fungal pathogens. However, applying said fungicides would require leaving the crop without the protective cover, hence exposing the crop to other hazards such as insects and mechanical damage. Furthermore, certain fungicides which are effective against the pathogenic fungi cannot be applied to certain crops for various reasons. For example Johnson spot, pitting disease (Pyricularia grisea) which attacks bananas and severely damages the fruit can be eradicated by applying the fungicide prochloraz. However, applying prochloraz to bananas and other crops with thin skins or peels was found to leave an undesired residual taste in the crop which makes the fruit unpalatable and inedible, as demonstrated by taint tests.

In view of the aforementioned there is a need to develop a method and means for protecting crops against fungal diseases which provides a solution to the aforementioned disadvantages.

It is therefore an objective of the present invention to provide a protective cover which protects the crop against fungal diseases.

A further objective of the present invention is to provide a method for protecting crop against pests including phytotoxic fungi. It is another objective of the present invention to provide a composition comprising a polymer and a fungicide which are suitable for the preparation of polymeric covers for protecting crop.

It is yet another objective of the present invention to provide a method for fungi control and a protective cover for crops that overcome the disadvantages of the prior art.

Other objectives of the invention will become apparent as the description proceeds.

Summary of the Invention

The present invention provides a cover for crops which provides protection of the crop against fungi, wherein said cover is of polymeric material which is impregnated with at least one fungicide. Optionally, said covering may further be impregnated with additional pesticides selected from among fungicides and insecticides. According to a further option said cover may comprise of an inner and outer layer, wherein only the inner layer is impregnated with a fungicide, and optionally a further pesticide.

According to a further aspect of the present invention there is provided a method for protecting crops against pre-harvest and post-harvest attack of fungal diseases comprising of covering the crop with the protective covering of the present invention.

A further aspect of the present invention provides compositions comprising a polymer and a fungicide (hereinafter "master batch") which are suitable for the preparation of the polymeric covers of the present invention.

Detailed Description of a Preferred Embodiment of the Invention

The following description is illustrative of embodiments of the invention. The following description is not to be construed as limiting, it being understood that the skilled person may carry out many obvious variations to the invention. Throughout the description, percentages indicated are by weight. The term pesticides as used throughout the description includes fungicides and insecticides. By crop it is meant, vegetables, fruits or the plants on which they grow.

The method of the present invention is based on creating an atmosphere of pesticide vapor in the volume encompassed by the cover surrounding the crop. It has now been surprisingly found that certain pesticides which when applied by dusting or spraying may have phytotoxic effects on the crop or may affect the taste of the crop, are not phytotoxic and do not affect the crop when applied according to the method of the present invention.

According to a particular embodiment of the present invention there is provided a method for protecting crops against fungal diseases, comprising of covering the crop with the protective cover of the present invention so that the volume surrounding the crop in the cover is filled with vapor of the fungicide which is released from the impregnated polymeric material of the cover. According to a further embodiment of the present method, the crop is covered with a protective cover which is impregnated with at least one fungicide and at least one additional pesticide, said pesticide being an insecticide. Thus, the volume surrounding the crop in the protective cover contains fungicidal and insecticidal vapor which protects the crop from fungal diseases and insects. When the cover is applied to fruit or clusters of fruit, the cover may remain on the cluster of fruit or crop after it is harvested and during transportation to provide further protection of the crop.

According to a particular embodiment the blossoms on a banana tree from which the fruit develops are covered with a bag constructed of polymeric material which is impregnated with at least one fungicide. Fungicidal vapor which is slowly released from the bag, fills the bag and thus protects the fruit from fungal diseases. Impregnating the bag with prochloraz will particularly be effective for protecting bananas from Pyricularia grisea without affecting the taste of the fruit nor displaying any phytotoxic effects. According to a preferred embodiment of the present method, the bananas are wrapped with a bag which is impregnated with prochloraz and chlorpyrifos so that the bananas are protected from fungal diseases and insects. The present method can be applied for pre-harvest and post-harvest protection to a wide variety of crops. When applied for the purposes of pre-harvest protection, the crop, e.g. the fruit or cluster of fruit, is covered by a protective cover of the present invention, preferably from the blossom stage. Preferred crops for which the present method may be applied for pre-harvest protection include: bananas, plantains, dorians, dates, citrus fruit, mango, avocado and pawpaws.

The present method, when applied for post-harvest protection of crops, comprises of covering the crop or the container in which the crop is stored, with a protective cover of the present invention. Preferred crops for the post-harvest application of the method of the present invention include: bananas, plantains, dorians, citrus fruit, papaya, mangos, stone fruit, pome fruit, avocados, grapes, melons, pineapples, pawpaws, strawberries, dates, mushrooms, eggplants and onions.

Non-limiting examples of phytopathogenic fungi which may controlled according to the present method include: pyricularia grisea, venturia inaequalis, colletotrichum gloeosporioides, glomerella cingulata, diplodia spp., monilinia laxa, colletrotichum spp., hypomyces tosellus, mycogone perniciose, verticillium fungicola, alternaria porri, botrytis allii, botrytis squamosa, alternaria alternate, dothiorella aromatica, botryodiplodia theobromae, penicillium expansum, penicillium spp., colletotrichum musae, trachyspaera fruitigena , botrytis cinera, diplodia, penicillium digitatum, penicillium italicum, ceratocystis paradoxa, botrytis.

Any of a wide variety of fungicides and insecticides may be employed in the present method in accordance to the particular fungi and pest which is to be controlled. Preferred fungicides include: N-propyl-N-[2-(2,4,6-trichlorophenoxy)ethyl] lH-imidazole- 1 - carboxamide (prochloraz); (±)-l-[2-(2,4-dichlorophenyl)-2-(2-propenyloxy)ethyl]-lH- imidazole (imazalil); (±)-α-butyl-α-(2,4-dichorophenyl)-lH-l,2,4-triazole-l-ethanol (hexaconazole); methyl[l-[(butylamino)carbonyl]-lH-benzimidazol-2-yl]carbamate (benomyl); (±)-α-[2-(4-chlorophenyl)ethyl]- -(l,l-dimethylethyl)-lH-l-l,2,4-triazole-l- ethanol (tebuconazole); α-[2-(4-chlorophenyl)ethyl)-α-phenyl-lH-l,2,4-triazole-l- propanenitrile (fenbuconazole); 2-(4-thiazolyl)-lH-benzimidazole (thiabendazole); α- butyl-α-(4-chlorophenyl)- \H- 1 ,2,4-triazole- 1 -propanenitrile (myclobutanil); and strobilurins. Preferred insecticides include: C,0-diethyl-O-3,5,6-trichloro-2- pyridinyl)phophorothioate (chlorpyrifos); 0, 0-diethyl-0-[6-methyl-2-(l-methylethyl)-4- pyrimidinyl) phosphorothioate (diazinon); pyrethroids; and neonicotinoids. For purposes of brevity the common names of chemical compounds will be used throughout the description and claims.

According to a particular embodiment of the present invention there is provided a protective cover for protecting crops against fungi, wherein said cover is constructed of polymeric material which is impregnated with at least one fungicide. The cover is constructed in the form of a bag, sleeve or sheet. The size of the cover and the contents of pesticides may be controlled in accordance to the crop in need of protection and the pest or fungi which are to be eradicated and against which protection is sought. According to a particular embodiment the material of which the protective cover is constructed contains

0.1% to 2% of at least one fungicide, yet a further embodiment the material of the protective cover contains 0.1% to 2%> of at least one fungicide and 0.1 % to 2% of at least one insecticide.

According to a preferred embodiment of the invention the protective cover is constructed of a single layer polymeric material in the form of a bag or sleeve, wherein said polymeric material is impregnated with at least one fungicide.

According to yet a further preferred embodiment the protective cover is constructed of a single layer polymeric material in the form of a bag or sleeve, wherein said polymeric material is impregnated with at least one fungicide and at least one insecticide.

According to a specific embodiment there is provided a bag constructed of polymeric material which is impregnated with prochloraz. According to yet a further specific embodiment said bag is impregnated with prochloraz and chlorpyrifos, such that said bag contains 0.1% to 2% and 0.1% to 2%> prochloraz and chlorpyrifos, respectively. According to a further embodiment of the invention there is provided a protective cover for crop which is constructed of polymeric material, comprising an inner and outer layer, wherein only the inner layer is impregnated with at least one fungicide. Optionally the inner layer may further be impregnated with additional pesticides. The outer layer functions as a protective layer so that the person coming in contact with the cover does not come in contact with the pesticides which are impregnated in the inner layer of the cover. The material of the inner layer may contain 0.1% to 2% of at least one fungicide and 0 to 2% of at least one insecticide.

The protective cover may be impregnated with various fungicides and insecticides in accordance to the particular fungi and pest which is to be controlled. Preferred fungicides include: prochloraz, imazalil, hexaconazole, benomyl, tebuconazole, fenbuconazole, thiabendazole, myclobutanil and strobilurins. Preferred insecticides include: chlorpyrifos, diazinon, pyrethroids and neonicotinoids.

The protective cover may be constructed of many types of polymeric material. Non- limiting examples of polymers suitable for the construction of the protective cover are homopolymers and copolymers of polyolefines selected from a group comprising of low density polyethylene (LDPE), low linear density polyethylene (LLDPE), high density polyethylene (HDPE), polypropylene (PP), ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA), derivatives or mixtures and blends thereof. Other polymeric materials can be used for the present invention, as may be appreciated by the skilled artisan.

By impregnation it is meant that the pesticide is included within the polymeric matrix.

Impregnation of the fungicide and pesticide in the polymeric material is accomplished by mixing the fungicide or pesticide with raw polymeric material, which is the raw material from which the polymeric cover is constructed (hereinafter "pre-mix"), prior to the final stage of constructing the cover. The pre-mix may come in the form of pellettes, melt, resin or solution. Mixing the pre-mix with a fungicide or pesticide provides the master batch, said master batch being a further aspect of the present invention. Processing the master batch to construct the protective cover provides a cover wherein the fungicide or pesticide is impregnated in the polymeric material of the cover. Processing of the master batch may be carried out according to various known methods in the art such as extrusion. Any of many known processing techniques may be employed in accordance to the type of polymer and form of construction of the protective cover, as may be appreciated by the skilled artisan. The master batch may be processed with additional resins in order to form the protective cover. The ratio between the master batch and additional resins may be controlled so that the desired percentage of pesticide in the protective cover is achieved.

The master batch of the present invention contains 5% to 50% of at least one fungicide. Optionally the master batch may contain at least one additional insecticide in the amount

5% to 50%. According to a particular embodiment the master batch contains 5% to 50% prochloraz. In yet a further embodiment the master batch contains 5% to 50% prochloraz, and 5% to 50% chlorpyrifos.

The pesticide impregnated in the protective cover is slowly released from the polymeric material. The rate of release of the pesticide from the polymeric material is controlled so that substantially most of the pesticide is released from the polymeric material by the end of the period of time for which protection is sought. Said period may be the growing season until the crop is harvested, the time of storage and transportation of the harvested crop, or a combination of both said periods. The rate of release of the pesticide from the polymeric material may be controlled by the amount and type of anti-block filler additives and type of polymer from which the polymeric material is prepared. Said additives described hereinafter. Other methods of controlling the rate of release may be employed as may appreciated by the skilled artisan.

The pre-mix and master batches of the present invention may further comprise additives that are intended for achieving the desired properties of the protective cover. The group of additives which are well known from the prior art comprises u.v. absorbents; anti-blocks which are based on amorphous and crystalline silicates; slip agents selected from among amides, oleamide, stearamide and derivatives thereof; lubricants selected from among polyolefine waxes, PE waxes and PP waxes and metal stearates; and anti-oxidants. Other additives may be applied as may be appreciated by the skilled artisan. The present invention presents the following advantages:

1. The cover provides constant fungi control after application of the cover without the need to reapply fungicides. 2. The method provides a safe mode of fungicide application. The fungicides are released slowly into the air surrounding the crop creating a cloud of fungicide vapor around the crop. Hence the exposure of people working in the field is minimal. This is in comparison to other application methods which involve handling, mixing of toxic chemicals and spraying or other methods of application of these chemicals. The spraying creates a hazardous mist which may be harmful to the person working in the field and to the environment.

3. The method provides post-harvest fungicidal protection during transportation of the crop. Thus post harvest reapplication of fungicides before transportation is reduced or eliminated. This is particularly important when residue levels of pesticides in the crop need to maintained very low.

The present invention provides a method of application of prochloraz to bananas and other sensitive crops that does not affect the taste of the crops while other methods of application of prochloraz does affect the taste of the banana and the crop and thus are not recommended.

While embodiments of the invention have been described by way of illustration, it will be apparent that the invention may be carried out with many modifications, variations and adaptations, without departing from its spirit or exceeding the scope of the claims

Claims

CLAΓMS

1. A protective cover for controlling fungi diseases in crops, wherein said cover is of polymeric material which is impregnated with at least one fungicide.

2. A cover according to claim 1 further impregnated with at least one additional pesticide selected from among fungicides and insecticides.

3. A cover according to claim 1 or 2 constructed of an inner and outer layer, wherein only the inner layer is impregnated with at least one fungicide.

4. A cover according to any of claims 1 to 3 wherein the fungicide is selected from among a group comprising of prochloraz, imazalil, hexaconazole, benomyl, tebuconazole, fenbuconazole, thiabendazole, myclobutanil and strobilurins.

5. A cover according to claims 2 wherein the additional pesticide is selected from among a group of insecticides including chlorpyrifos, diazinon, pyrethroids and neonicotinoids..

6. A cover according to claim 2 impregnated with prochloraz and chlorpyrifos.

7. A cover according to any of claims 1 to 6 wherein said cover is impregnated with 0.1% to 2% fungicide.

8. A cover according to any of claims 2, 3, 5 or 6 wherein said cover is impregnated with 0.1 % to 2% insecticide.

9. A cover according to any of claims 1 to 8 wherein said cover is in the form of a bag or sleeve.

10. A method for protecting crops against fungal diseases comprising of covering the crop with the protective covering of any of claims 1 to 9.

11. A method according to claim 10 for the protection of crops against fungal diseases wherein said fungal diseases are selected from among pyricularia grisea, venturia inaequalis, colletotrichum gloeosporioides, glomerella cingulata, diplodia spp., monilinia laxa, colletrotichum spp., hypomyces tosellus, mycogone perniciose, verticillium fungicola, alternaria porri, botrytis allii, botrytis squamosa, alternaria alternate, dothiorella aromatica, botryodiplodia theobromae, penicillium expansum, penicillium spp., colletotrichum musae, trachyspaera fruitigena ,botrytis cinera, diplodia, penicillium digitatum, penicillium italicum, ceratocystis paradoxa, botrytis.

12. A method according to claim 10 wherein the crop is selected from among a group comprising of bananas, plantains, dorians, citrus fruit, papaya, mangos, stone fruit, pome fruit, avocados, grapes, melons, pineapples, pawpaws, strawberries, dates, mushrooms, eggplants and onions.

13. A method according to claim 10 for pre-harvest and post-harvest protection of crops.

14. A polymeric composition comprising a polymer and a fungicide which is suitable for the preparation of the covers of claims 1 to 9.

15. A polymeric composition of claim 14 further comprising an insecticide.

16. A polymeric composition according to claims 14 and 15 wherein the fungicide is selected from among a group comprising of prochloraz, imazalil, hexaconazole, benomyl, tebuconazole, fenbuconazole, thiabendazole, myclobutanil and strobilurins.

17. A polymeric composition according to claims 15 wherein the insecticide is selected from among a group of insecticides including chlorpyrifos, diazinon, pyrethroids and neonicotinoids.

8. A polymeric composition according to any of claims 14 to 17 containing 5% to 50% fungicide, insecticide or mixture thereof.