Abstract:
Composition for the treatment of plants, that is a structural combination of agro-materials and adjuvant formulations. A specific composition is a particulate material in which the agro-material particle constitutes the nucleus of each composition particle and adjuvant formulations constitute a coating of the composition particle. The adjuvant formulations comprise a plurality of components, which constitute substantially superimposed coating layers in each particle of the composition and preferably comprise a combination of lipophilic and hydrophilic cuticle surface active agents, wetting agents, thickening agents and fatty self-emulsified components. Special compositions are those in which different agro-materials are used. The agromaterials are chosen from fertilizers, trace elements, plant growth regulators, biostimulants, pesticides, herbicides and insecticides. The invention also relates to methods of treating plants by applying the agro-material compositions, and to methods of preparing the agro-material compositions.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to compositions for the treatment of plants, which combine agro-materials with adjuvants having a multi-layer structure, said adjuvants allowing a controlled penetration, and particularly a long-lasting penetration, of the agro-materials through the plant&#39;s skin, while lowering the application costs and the risk of damaging the plant&#39;s tissues.  
       BACKGROUND OF THE INVENTION  
       [0002]     The term “agro-materials”, as employed in this specification and claims, particularly includes any materials chosen from the group consisting of fertilizers, trace elements, plant growth regulators, biostimulants, pesticides, herbicides and insecticides. However, any materials affecting the growth of plants, or serving a desirable purpose in dealing with vegetable crops, are to be considered included in the said term. The term “plant” is used herein to designate any vegetable crop and involves no limitation of the kind of crop treated according to the invention.  
         [0003]     The plant&#39;s skin hereinafter “cuticle membrane” or “CM”) is the main barrier to the penetration of agro-materials into the plant&#39;s tissues. The CM network is made of alkanes, alkenes, fatty acids and fatty alcohols. It contains also an amorphous fraction made of terpenes and other aromatic compounds.  
         [0004]     Agro-materials are often applied in aqueous solution or suspension, that is preferably sprayed on the plants to be treated. The penetration of agro-materials into the plant&#39;s tissues occurs by diffusion through the CM. The molecular size of the applied agro-material and its electrolytic nature determine its ability to penetrate through the CM. In order to enable an efficient diffusion through the CM, surfactants containing wetting, sticking and spreading agents are usually included in the spraying solution. Surfactants are so selected as to address the cuticle surface properties. There are, for example, several formulations on the market based on organo-silicones that are good spreaders, but that, on the other hand, cause an irreversible damage to the plant&#39;s tissues.  
         [0005]     Environmental humidity, temperature and irradiation in the habitat of the sprayed plant control the rate of water evaporation from the sprayed solution and consequently determine the crystallization time of the applied agro-materials. Crystallization usually occurs between 0.5 and 2 hours subsequent to spraying. After crystallization, any further diffusion of the agro-material into the plant&#39;s tissues completely stops. In many cases, particularly under extremely high temperatures, high irradiation and low humidity conditions, fast crystallization occurs, resulting in a severe damage to the plant&#39;s tissues. Also, a too fast penetration rate can damage the plant&#39;s tissues, particularly when the sprayed solution is highly concentrated. Attempts to use polyethylene glycol to reduce the evaporation rate of the sprayed drops and thus to reduce the damage to the plant&#39;s tissues and delay crystallization, have not yielded satisfactory results.  
         [0006]     The prior art has attempted to facilitate and control the penetration into plants&#39; tissues, and generally to improve the action of agro-chemicals, by adding to them auxiliary compositions. Any such composition will be called hereinafter “adjuvant”. Thickening agents, such as polysaccharides, are included in some prior art adjuvant formulations, used for spray application of fertilizers and pesticides, for the purpose of extending the life span of the sprayed drops: see U.S. Pat. No. 5,389,386, U.S. Pat. No. 6,074,987, U.S. Pat. No. 6,093,682 and EP 0784040. However, the adjuvant formulations disclosed in said patents and in other prior art publications do not provide a significant control of the rate of penetration and particularly do not provide long-lasting penetration of agro-materials, as is desirable to minimize toxicity to the plant and to reduce the number of applications required for a desired biological result.  
         [0007]     It is known in the art that non-electrolytic compounds, such as urea, better penetrate through biological membranes, the plant&#39;s CM included, than species of a more electrolytic nature, such as mono-potassium phosphate (MKP). In many cases undesired anchoring of the electrolyte species onto the ionized CM occurs and said species do not reach the plant&#39;s tissues.  
         [0008]     In order to enhance the diffusion through the CM, mediators are required that function by partially saturating the binding sites in the CM and/or modifying its elasticity and plasticity, resulting in enhancing its permeability to ionized agro-materials.  
         [0009]     WO 00/05953 of the present inventors, the contents of which are incorporated herein by reference, discloses liquid adjuvant systems, comprising a wetting agent, a polysaccharide and a plasticizer, and demonstrates the ability to use a cocktail of adjuvants for obtaining better performance in foliar fertilization than that exhibited by other prior art. However, the said adjuvants have two drawbacks. One drawback is the separation from the adjuvant mixture, during shipping or storing, of the polysaccharide, which constitutes a critical ingredient. Thus, the adjuvants disclosed in WO 00/05953, while effective when freshly prepared, lack stability in shipping and storing. The other drawback is that the said adjuvants do not afford complete protection from the atmosphere of both the agro-material and of the polysaccharide, resulting in a diminished biological effectivity of the agro-materials. For example, Fe 2+  rapidly oxidizes to Fe 3+  and MKP crystallizes shortly after application due to fast evaporation.  
         [0010]     It is an object of the present invention to provide compositions of agro-materials and adjuvants, which allow a controlled penetration rate of the agro-materials into the plant&#39;s tissues, and particularly allow a long-lasting penetration.  
         [0011]     It is another object of the present invention to provide a particulate material combining agro-materials and adjuvants in a structure in which the agro-materials form the nuclei of the particles and the adjuvants form coatings of said nuclei.  
         [0012]     It is a further object of the present invention to provide such a particulate material wherein the adjuvants comprise a plurality of components, including solid and semi-solid components.  
         [0013]     It is a still further object of the present invention to provide a method for protecting agro-materials against atmospheric oxidation.  
         [0014]     It is a still further object of the present invention to provide protected agro-materials that are stable in shipping and storing.  
         [0015]     It is yet a further object of this invention to provide methods of treating plants by employing the said structural combinations of agro-materials.  
         [0016]     It is a still further object of the present invention to provide a method for applying agro-materials to vegetable crops, which improves the metabolism of the agro-materials in the plant, reduces the risk of damaging the plant&#39;s tissues and reduces the application costs.  
         [0017]     It is a still further object of the present invention to provide structural combinations of agro-materials and adjuvants, which causes an improved metabolism of the agro-materials when applied to vegetable crops.  
         [0018]     Other purposes and advantages of the invention will become apparent as the description proceeds.  
       SUMMARY OF THE INVENTION  
       [0019]     The present invention provides a novel composition, sometimes called hereinafter “agro-composition”, that is a structural combination of agro-materials and adjuvant formulations. Said composition forms a particulate material, wherein an agro-material particle constitutes the nucleus of each composition particle and the adjuvant formulations constitute a coating of the composition particle. Preferably, the adjuvant formulations comprise a plurality of components, and more preferably, said components constitute substantially superimposed coating layers in each particle of the composition. Preferably, the adjuvant formulations comprise a combination of lipophilic and hydrophilic cuticle surface active agents, wetting agents, thickening agents and fatty components. Cuticle surface active agents are sorbed into the CM, following which they enhance the penetration of the agro-material.  
         [0020]     In an embodiment of the invention, the agro-composition additionally comprises solid or semi-solid, preferably inert, materials with the same or different adjuvant formulation absorbed therein. These materials which are preferably semi-solid, particularly gel-like, can be applied to the naked or already coated core, creating an adjuvant layer thereon. Such additional layer/s increase the amount of adjuvant in the agro-composition.  
         [0021]     The preferred adjuvant formulations include wetting and surface active agents that optimize the spreading and sticking of the composition particles to the plant&#39;s CM. They also include thickening agents, such as polysaccharides, that delay crystallization of the agro-chemicals. The adjuvant&#39;s components may optionally be sorbed into a solid or semi-solid carrier made of such materials as fumed silica or clay, and the carrier sorbed with the adjuvant may be used to form a coating layer over the core particle. The addition of a solid or semi-solid adjuvant coating layer may contribute to preserving the integrity of the system, rendering it stable during storing and shipping.  
         [0022]     Unlike solid adjuvants of prior art, such as described in U.S. Pat. No. 4,874,423, U.S. Pat. No. 6,074,987 and in other publications, there are also included in the solid or semi-solid adjuvants of the present invention lipid components that can either enhance or retard the penetration rate of the agro-material. Determining the penetration rate of the agro-material serves two purposes: to optimize its metabolism in the plant and to reduce the risk of toxic effects. To the best of the inventors&#39; knowledge there have not been disclosed compositions that can exert a long-term effect on the mobilization of agro-materials through the plant&#39;s CM.  
         [0023]     The following Examples demonstrate some ranges of weight ratios between the different components of the agro-composition.  
         [0024]     In a preferred embodiment of the invention, the composition is a particulate material in which each particle has a core of an agro-material, as herein defined, coated by several, superimposed layers consisting of a polysaccharide, a solid fat (having a relatively high melting point), a fatty alcohol and an esterified vegetable oils containing self-emulsifier. The particles may have identical cores, i.e. all being of the same agro-material, or have core of different agro-materials.  
         [0025]     The polysaccharide component, due to its hydrophilic nature, sticks to the core and fully covers it. The polysaccharide layer is covered by a solid fat layer, which in turn is covered by a fatty alcohol layer. The top layer is made of a mixture of liquid vegetable oils. The order of layers is determined by the differences in the specific gravity of the lipid components. The said layers are substantially superimposed, by which expression is meant that the layers are not sharply separated, and any two adjacent layers are partially mixed at their interface.  
         [0026]     The multi-layer structure of the particles of the composition of the invention affords the following advantages: 
        a) A full and uniform covering of the core.     b) An improved spreading of the agro-material over the plant&#39;s CM.     c) The prevention of caking of the composition particles.     d) The prevention of the oxidation of oxidation-sensitive agro-materials.     e) The control of the penetration rate (and penetration duration) of the agro-material, particularly allowing a long-lasting penetration through the plant&#39;s cuticle membrane and internal membranes.     f) The adhesion of the sprayed material to the plant&#39;s CM, which reduces the amount lost during rainfall, and droplets rebound effect, off the leaf.     g) The reduction of the application costs.     h) The prevention, or at least reducing of any damage to the plant&#39;s tissues.        
 
         [0035]     The hydrophilic polysaccharide tends to absorb water produced during transpiration. The top-coated lipid layers inhibit water evaporation, enabling a moderate, long-lasting diffusion of the agro-material into the plant&#39;s tissues. The lipid components in the composition of the present invention also plasticize the cuticle membrane by inducing moderate (and reversible) disorder in it, which allows partial absorption of the polysaccharide into the plant&#39;s epicuticular wax layer (the main barrier to penetration). The agro-material, due to its strong adhesion to the polysaccharide, is thus afforded a pathway in the CM and can slowly diffuse through it.  
         [0036]     The compositions of the present invention allow the loading of high concentrations of agro-materials (up to 10% of salts) onto the plant without harming the tissues. As a result, fewer spray applications are needed to achieve desired biological effects, thereby improving the cost-effectiveness of agricultural spray applications.  
         [0037]     Surprisingly, the agro-compositions of the present invention are found to allow exceptionally long penetration duration of agro-nutrients, up to three weeks under common field conditions, without harmfully affecting the plant&#39;s foliage. By contrast, prior art compositions, in particular adjuvant formulations, provided only considerably shorter diffusion times, never exceeding 24 hours. Additionally, the compositions of this invention have improved spreading and sticking to the plant&#39;s CM surface. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0038]     As stated hereinbefore, the term “agro-materials”, as employed in this specification and claims, includes, but is not limited to, any materials chosen from the group consisting of fertilizers, trace elements, plant growth regulators, biostimulants, pesticides, herbicides and insecticides. In a preferred embodiment of the invention, the agro-material may comprise one or more material(s) of the following classes: 1) at least one fertilizer, preferably containing at least one element selected from the group consisting of potassium, nitrogen, phosphorous and mixtures thereof; 2) at least one micro-element, preferably selected from the group consisting of iron, zinc, boron, magnesium, manganese, copper, calcium and mixtures thereof, 3) at least one plant growth regulator, preferably selected from the group consisting of auxin, gibberelline, cytolinine, ethylene, abssicic acid, a growth retardant, jasmonic acid, polyamine, brassinolid, salicylic acid and mixtures thereof.  
         [0039]     The agro-material may be also 4) an insecticide, preferably selected from the group consisting of insect growth regulators, organo-phosphorus compounds, carbamides, thiocarbamides and mixtures thereof; 5) an herbicide, preferably selected from a group consisting of Bromasil, Dioron, Glyphosate, and mixtures thereof; 6) a biostimulant, preferably selected from the group consisting of humic acid, amino acids, sea weed, algae and mixtures thereof.  
         [0040]     The adjuvant formulations, which, combined with one or more of the said agro-materials, form preferred embodiments of the compositions of this invention, may include: a) at least one surface active agent; b) at least one thickening agent; c) at least one high melting point fat; d) at least one fatty alcohol; e) at least one esterified vegetable oil containing a self-emulsifier; f) at least one epoxified triglyceride.  
         [0041]     In a second preferred embodiment of the present invention, said solid or semi-solid substrate is a non-agro-material solid or semi solid, such as fumed silica, that functions as a carrier to the adjuvant mixture, which is absorbed therein, wherein a layer or layers of said solid or semi-solid carrier, absorbed with said adjuvant components, can be coated onto the said core of agro-material, or over a core which is already adjuvant-coated. Alternatively, said solid or semi-solid carrier is made of clay. Fumed silica and clay, which are very fine flowable powders and highly porisivic, are particularly suitable carriers, and can acquire gel-like properties when loaded beyond their absorption capacity. Thus, when loading these carriers with the “adjuvant cocktail”, that part of the cocktail which is not absorbed, particularly the polysaccharide-oil mixture, remains out of the powder pores and confers gel-like properties.  
         [0042]     The compositions of the present invention are preferably used contained in agrochemical formulations, preferably aerosol or spay formulations. Such formulations are prepared by suspending the composition in a suitable solvent, preferably water.  
         [0043]     Most preferred are the formulations Nos. 1 to 6 described in the Examples.  
         [0044]     In a further aspect, the invention relates to methods of treating plants by applying to the plants, preferably to the foliage, a composition of the invention or a formulation comprising the same. The methods of the invention are intended, but not limited to long-lasting foliar application of macroelements pre-blooming long-lasting foliar application of macro and trace elements, long-lasting foliar application of trace elements, particularly iron or other oxygen-sensitive elements, and improving mechanical harvesting of fruit bearing plants by reducing fruit retention force.  
         [0045]     The advantages of applying the compositions or formulations of the invention are demonstrated in the following Examples.  
         [0046]     Still further, the invention relates to a process for preparing the compositions of the invention, which comprises: 
        a) preparing a homogeneous mixture of adjuvant formulation components,     b) preparing a fine crystal powder of the agro-materials,     c) spraying said mixture on said powder while rotating and heating said powder, whereby to coat the particles of said powder,     d) cooling while rotating said coated powder particles, and     e) drying said coated powder particles.        
 
         [0052]     In another embodiment, the invention relates to a process for preparing a composition according to the invention, which comprises: 
        a) providing at least one agro-material in particulate form and a solid or semi-solid carrier;     b) preparing a homogeneous adjuvant mixture of adjuvant formulation components,     c) spraying said adjuvant mixture over said at least one agro-material,     d) sorbing said adjuvant mixture into said solid carrier,     e) applying the carrier sorbed with said adjuvant mixture obtained in step d) onto the particles obtained in step c),     f) optionally spraying the particles obtained in step e) with said adjuvant mixture,     g) cooling the particles obtained in step e) or step f), and     h) allowing the cooled agro-material obtained in step g) to dry.        
 
         [0061]     In a particular embodiment of this process more than one agro-material in particulate form is employed.  
         [0062]     Disclosed and described, it is to be understood that this invention is not limited to the particular examples, process steps, and materials disclosed herein as such process steps and materials may vary somewhat. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments only and not intended to be limiting since the scope of the present invention will be limited only by the appended claims and equivalents thereof.  
         [0063]     It must be noted that, as used in this specification and the appended claims, the singular forms “a”, “an” and “the” include plural referents unless the content clearly dictates otherwise.  
         [0064]     Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.  
         [0065]     The following Examples are representative of techniques employed by the inventors in carrying out aspects of the present invention. It should be appreciated that while these techniques are exemplary of preferred embodiments for the practice of the invention, those of skill in the art, in light of the present disclosure, will recognize that numerous modifications can be made without departing from the spirit and intended scope of the invention.  
       EXAMPLES  
       [heading-0066]     I—Adjuvant Ingredients  
         [0067]     Oils: 
        Vegeol SPO R , a vegetal oil plus emulsifier used as spreader and plasticizer (Aarhus, Denmark).     Castor oil, spreader and plasticizer.     Vernonia oil, epoxified triglyceride, plasticizer.        
 
         [0071]     Fats: 
        COATEX 21 R , stearin solid fat. Used for gum gels coatings (Aarhus, Denmark).        
 
         [0073]     Waxes: 
        Jojoba—liquid plant wax. Retarding the rate of penetration of materials through the plant&#39;s CM.     Plastinol R —mineral hydrocarbon wax replacer. Used for gum coating and retarding penetration (Loders Croklean, The Netherlands).        
 
         [0076]     Detergents: 
        Triton X-100 R , surfactant (Sigma, U.S.A.).     Tween 20 R , surfactant (Sigma, U.S.A.).     Optima R , surfactant and cuticle plasticizer (Helena, U.S.A.).     Induce, surfactant and cuticle plasticizer (Helena, U.S.A.).     Dehydol LT-6 R , plasticizer and accelerator of penetration (Henkel, Germany).        
 
         [0082]     Polysaccharides: 
        Derivatized guar gum, sticker and anti-evaporative agent (Economy Polymers, U.S.A.).     Glucopon HH/EC 600 R , plasticizer and penetration accelerator (Henkel, Germany).        
 
         [0085]     Absorbents: 
        Tixoseal R , fumed silica (Airosil 300 R , Airosil 380 R  and Airosil 972 R ).     clay (oil dry, U.S.A.).     calcium silicate.        
 
         [0089]     Fertilizers: 
        MKP and phosphoric acid were from Rotem Amfert Negev (Israel).     KNO 3  was from SQM, Chile 
 
 II—Adjuvant Formulations 
       
 
         [0093]     In all of the following formulations (1 to 6) water was used as the solvent (.  
         [0094]     Formulation 1:  
                                           Wide range   Preferred range           % w/w in   % w/w in spraying       MKP-Nutri-Vant   spraying formulation   formulation                   MKP   1-5   1-3       Vegeol SPO R     0.01-2     0.1-1         Vernonia oil   ″   0.05-0.2        Coatex 21 R     ″   0.05-0.2        Induce R     ″   0.1-0.3       Optima R     ″   0.1-0.3       Dehydrol LT-6   ″   0.1-0.3       Derivatized guar gum   ″   0.1-1                    
 
         [0095]     Formulation 2:  
                                           Wide range   Preferred range           % w/w in spraying   % w/w in spraying       MKP-Nutri-Vant II   formulation   formulation                   MKP   1-5   1-3       Vegeol SPO R     0.01-2     0.1-1         Tween 20 R     ″   0.1-0.3       Coatex 21 R     ″   0.05-0.2        Jojoba wax   ″   0.05-0.2        Induce R     ″   0.1-0.3       Derivatized guar gum   ″   0.1-1                    
 
         [0096]     Formulation 3:  
                                               Preferred range           Wide range % w/w   % w/w in       Nutri-Vant III   in spraying formulation   spraying formulation                   KNO 3     1-7   1-4       MKP   1-5   1-3       2,4-Dp   0.001-0.1    0.001-0.01        Vegeol SPO R     0.01-2     0.1-1         Tween 20 R     ″   0.1-0.3       Coatex 21 R     ″   0.05-0.2        Jojoba wax   ″   0.05-0.2        Induce   ″   0.1-0.3       Derivatized guar gum   ″   0.1-1                    
 
 2,4 dichlorophenoxy propionic acid (2,4-Dp) was from Sigma, USA. 
 
         [0098]     Formulation 4:  
                                               Preferred range           Wide range % w/w   % w/w in spraying       Olive-Nutri-Vant R     in spraying formulation   formulation                   Urea    0.5-3   0.5-1.5       MKP     1-5   0.1-3         Boric acid    0.5-4   0.5-2         Castor oil   0.01-2   0.1-1         Tween 20 R     0.01-2   0.1-0.3       Plastinol R     0.01-2   0.05-0.2        Coatex 21 R     0.01-2   0.05-0.2        Induce R     0.01-2   0.1-0.3       Optima   0.01-2   0.1-0.3       Derivatized guar gum   0.01-2   0.1-1                    
 
         [0099]     Formulation 5:  
                                           Wide range   Preferred range           % w/w in spraying   % w/w in spraying       Ferri-Vant R     formulation   formulation                   Fe 2 (SO 4 ) 3     0.01-1   0.1-0.8       Vegeol SPO R     0.01-1   0.1-0.3       Tween 20 R     ″   0.01-0.1        Jojoba wax   ″   0.01-0.1        Plastinol R     ″   0.01-0.1        Coatex 21 R     ″   0.01-0.1        Induce R     ″   0.01-0.1        Derivatized guar gum   ″   0.1-0.3       Tixoseal R     ″   0.01-0.05                  
 
         [0100]     Formulation 6:  
                                           Wide range   Preferred range           % w/w in spraying   % w/w in spraying       HarvestVant R     formulation   formulation                   MKP   1-5   1-3       DKP   0-3   0-2       Ethephon   0.01-1     0.05-0.15       Phosphoric acid   0.01-1     0.05-0.01       Humic acid   0.01-0.5    0.05-0.1        Vegeol SPO R     0.01-1     0.1-0.3       Tween 20 R     ″   0.01-0.1        Jojoba wax   ″   0.01-0.1        Plastinol R     ″   0.01-0.1        Coatex 21 R     ″   0.01-0.1        Induce R     ″   0.01-0.1        Derivatized guar gum   ″   0.1-0.3       Tixoseal R     ″   0.01-0.05                  
 
 III—Composition Preparation Procedures 
 
 Procedure A: 
 
         [0103]     Liquid adjuvant cocktail containing the specific list of oils, fats, waxes, detergents and polysaccharides for each formulation is preheated to 35-45° C. and mixed well for about 30 minutes until a homogenous solution is obtained. The cocktail is then poured into a sprayer atop a rotating pan heated to 35-45° C. in which a fine crystal powder of the agro-material or a mixture of agro-materials is placed. The cocktail is sprayed on the agro-material crystals during rotation, the heating is replaced with a cool air pan and the mixture is rotated for a further 30 minutes, after which the coated agro-material is dried for several hours.  
         [0104]     The above procedure is followed when a ratio in the range of 10:1 to 20:1 w/w between the agro-material crystals and the adjuvant cocktail is required.  
         [heading-0105]     Procedure B:  
         [0106]     When a ratio of between 1:2 and 1:5 w/w between the agro-material and the adjuvant cocktail is required (such as in the case of trace elements and more particularly of iron), a different procedure is followed (which will be described, by way of example, with reference to Fe 2 (SO 4 ) 3  as the agro-material, but can be carried out with any other agro-material).  
         [0107]     3 kg of Fe 2 (SO 4 ) 3  are initially sprayed with 0.75 kg pre-heated (35-45° C.) well-mixed liquid adjuvant cocktail (see Formulation 5, all ingredients but for the Fe 2 (SO 4 ) 3  and the Tixoseal R ). In a second step, 0.468 kg of the cocktail absorbed on 0.156 fumed silica (Tixoseal R ) are mixed with the initially sprayed Fe 2 (SO 4 ) 3 . The Tixoseal R  allows to load enough adjuvant cocktail onto the Fe 2 (SO 4 ) 3  crystals to reach a ratio of 3:1 w/w and to avoid separation of the components. Finally, another 0.281 kg of liquid adjuvant cocktail is sprayed on the crystals, already adsorbed with a layer of the adjuvant-sorbed Tixoseal R , to ensure a multi-layer uniform coating. The product is then cooled and permitted to dry.  
         [heading-0108]     Procedure C:  
         [0109]     When it is required to separate between various components of the agro-material mixture in the coated formulation to keep its activity and to prevent the release of one compound after long storage as a gas, such as in the case of “HarvestVant™”, containing of MKP, DKP, Humic acid and ethylene forming agent—Ethephon—specifically designed for loosening fruit retention force (Ethephon quickly decomposes to ethylene under alkaline and high temperature conditions), a three-envelope coating procedure is operated.  
         [0110]     In the initial step Ethephon is sorbed onto fumed silica (Tixoseal) and then pre-heated (35-45° C.). Well mixed liquid adjuvant cocktail (see Formulation 6 ) is sprayed to form the first envelope. A second envelope of the same adjuvant cocktail is formed on the other ingredients of the formulation (MKP, DKP, Phosphoric acid and Humic acid). The two coated batches are mixed together well and another pre-heated well mixed same liquid adjuvant cocktail is sprayed to form the third envelope coating of the final formulation. The product is then cooled and allowed to dry.  
         [heading-0111]     IV—Experimental Results  
       Example 1  
       [heading-0112]     Effect of MKP-Nutri-Vant R  I on the Percent of Penetration of Phosphorous ( 32 P) Through Citrus Grandis Isolated Cuticles  
         [0113]     The experiment was carried out for three weeks in a controlled shaking chamber set at 60% relative humidity and 25° C. The values are calculated from the transformation formula −ln(1−M t /M o ). M t  is the accumulation of radioactivity penetrated in each time period tested; M o  is the total radioactivity applied to the isolated cuticle, based on Schönherr and Riederer [Schonherr, J. and M. Riederer, Plant Cell Environ. 4:349-354 (1986)]. The values are the means of at least 20 replicates ±S.E.  
                                                                                             TABLE I                           % Penetration of  32 P                Treatment Hours                0   24   48   96   168   336   504                        (1) MK 32 P*   0   2.6 ± 0.8   3.4 ± 1.1   5.7 ± 1.4   6.3 ± 1.9   7.5 ± 1.6   7.9 ± 1.9       alone       (2) MK 32 P* + Nutri-   0   3.7 ± 0.9   21.2 ± 1.6    36.1 ± 2.2    42.0 ± 1.6    54.4 ± 1.9    67.2 ± 2.4        Vant I                 *MK 32 P: Monopotassium phosphate 1.0 mci, 3%, MBq specific activity, Biotec, Israel, coated with: Vegeol SPO R , Vernonia oil, Coatex 21 R , Indu ce R , Optima R , Dehydol LT-6 R  and derivatized guar gum 0.7%.             
 
       Example 2  
       [heading-0114]     Effect of MKP-Nutri-Vant II on the Percent of Penetration of Phosphorous ( 32 P) into Citrus Grandis Leaves  
         [0115]     The experiment was carried out for two weeks in a controlled shaking chamber set at 60% relative humidity and 25° C. All the details are similar to those in the previous table.  
                                                   TABLE II                           % penetration of  32 P                Treatment Hours                0   48   96   168   336               (1) MK 32 P*   0   3.1 ± 0.8   4.7 ± 0.6   5.5 ± 0.6   6.4 ± 0.4       alone       (2) MK 32 P +   0   4.4 ± 0.6   5.2 ± 0.4   6.9 ± 0.5   8.5 ± 0.6       Solvent L-77*       (3) MK 32 P** +   0   1.9 ± 1.2   5.4 ± 0.8   12.9 ± 0.8    18.3 ± 3.4        Nutri-Vant II                 *reference formulation (0.2% w/w).            **MKP (3% w/w) coated with: Vegeol SPO R , Tween 20 R , Coatex 21 R , Jojoba wax, Induce R , derivatized guar gum (0.2% w/w).             
 
       Example 3  
       [heading-0116]     Effect of Ferri-Vant (Multi-Layer Adjuvant Coated Fe 2 (SO 4 ) 3  on the Biological Activity of Iron Sprayed on Citrus Lemon Urika Chlorotic Foliage  
         [0117]     Changes in leaf color, chlorophyll level, iron content and leaf burns were examined ten days after application. The Ferri-Vant effect was compared with the untreated control, Fe 2 (SO 4 ) 3  sprayed alone and Fe 2 (SO 4 ) 3  treated with the surfactant Silwet R  L-77. Ten leaves from five trees sprayed for each treatment were sampled and scored for green color. The scoring was based as follows: 1—yellow leaves; 2—light green leaves; 3—vigorously green leaves. Chlorophyll level was determined spectrophotometrically as reported by Moran [Moran, R., Plant Physiol. 69:1376-1381 (1949)]. Iron content was obtained using the ICP system and leaf burns were visually detected.  
                                                                         TABLE III                                               Iron                   Chlorophyll level   Content           Leaf Color   at day 4*   at day4   Leaf Burns            Treatment/Day   0   2   4   10   Chl. A   Chl. B   (mg/g)   at Day 4               (1) control   1   1   1.1 ± 0.3   1 ± 0   2.6   1.1   0.60   −       (untreated)       (2) Fe 2 (SO 4 ) 3     1   1   1.3 ± 0.4   1.2 ± 0.4   2.8   1.2   0.61   −       alone       (3) Fe 2 (SO 4 ) 3  + Silwet   1   1.2 ± 0.4   1.5 ± 0.5   1.6 ± 0.5   5.1   2.1   0.64   +       L-77       (4) Ferri-Vant**   1   1.6 ± 0.5   2.0 ± 0.8   2.2 ± 0.8   9.2   4.6   0.69   −                 *mg/sq. cm leaf area.            **Ferri-Vant R : Fe 2 (SO) 4  (Deshanim and Chemical Compounds, Israel, 0.2% w/w) coated with: Vegeol SPO R , Tween 20 R , Jojoba wax, Plastinol R , Coatex 21 R , Induce R , Derivatized guar gum, Tixoseal R  (0.1% w/w).             
 
       Example 4  
       [heading-0118]     Effect of Spring Pre-Bloom Spraying with Olive-Nutri-Vant (Multi-Layer Adjuvant Coating Nutrient Mix Consisting of MKP, Urea and Boric Acid) on the Yield of Olive ‘Nabali’ as Determined Six Months Later, at Harvest  
         [0119]     This experiment was carried out in two consecutive years (1999 and 2000) at Givat Yo&#39;av orchard in northern Israel. The effect of Olive-Nutri-Vant R  was compared to an untreated control and to the same nutrient content tank mixed with a common surfactant.  
                                                                             TABLE IV                           No. of   Average yield ′99   Total yield ′99   Average yield ′00   Total yield ′00   Total yield ′99&amp;00   Percent       Treatment   Trees   (kg/tree)   (kg/10 3  sq · m.)   (kg/tree)   (kg/10 3  sq · m.)   (kg/10 3  sq · m.)   of control                                Control-untreated   23   1.2   45.0   51.8   1865.0   1910.0   100.0       Nutrients + Triton   45   2.3   82.0   51.9   1871.0   1953.0   102.2       X-100       Olive-Nutri-Vant   44   15.8   571.0   49.5   1872.0   2353.0   123.2                 *Olive-Nutri-Vant: MKP/urea/boric acid (3:1:05% w/w) coated with Castor oil, Tween 20, Plastinol, Coatex 21, Induce, Optima, Derivatized guar gum (0.2% w/w).             
 
       Example 5  
       [heading-0120]     Effect of the Three-Envelope Coating Procedure of HarvestVant on the Stability of the Product in Storage and its Activity on Loosening Olive Fruit Retention Force  
         [0121]     Ethylene-releasing compounds are known to stimulate abscission zone in the stem of olive fruits [Goren, et al., J. Amer. Soc. Hort. Sci. 123:545-549 (1998)]. Phosphorus compounds and mainly Ethephon release ethylene when decomposed and improve mechanical harvesting of fruits. This process is significantly catalyzed in alkaline conditions. Harvestvant™ contains a mixture of phosphorus compounds releasing ethylene, coated with Formulation 5 (without iron oxide). However, the stability of the product after storage is significantly reduced, due to decomposition of the Ethephon by the other relatively alkaline phosphorus compounds (mainly DKP and in less extent by MKP). To overcome this stability obstacle of the product, a three-envelope coating procedure was developed (see Procedure C).  
         [0122]     Using the Tseng et al, method for determination of Ethephon residue in agricultural products [Tseng et al, J. Food and Drug Analysis 8:213-217 (2000)], Ethephon was analysed by gas chromatography. As shown in Table V, after storage of the product for 45 days almost all (98%) of the Ethephon introduced to the original formulation was recovered in the three-envelope coating procedure. In the regular, one coating procedure, 65% of the Ethephon was recovered in comparison to 5% Ethephon recovery in the non-coated product that was based only on mixing the same ingredients.  
         [0123]     The activity of the three products on loosening olive fruit retention force was tested in commercial olive plantation and the results clearly indicated the differences in the stability of the products. The non-coated product did not make any difference in term of FRF value in comparison to unsprayed trees. The HarvestVant™ product with one regular coating reduced the FRF value in comparison to the control but was considerably lower than the FRF value of the three-envelope coated product. In order to improve mechanical harvesting of olives it is required to loosen FRF value under 200 gr, at least in the tested variety. Additionally, to keep the product active for long term it is essential to prevent the decomposition of Ethephon, since in the HarvestVant™ product the level of Ethephon that is applied to the tree is 2.5 fold lower than the recommended amount when using this product alone.  
                       TABLE V                           Ethephon recovery (%)   Activity of the       Treatment   after 45 days of storage   product FRF (gr)                   (1) Control (non-treated)       350       (2) Non coated mixture*    5%    350 ± 45**       (3) HarvestVant   65%   240 ± 30       one envelope procedure       (4) HarvestVant   98%   120 ± 40       three envelope procedure                 *The mixture of ingredients of all of treatments consisted of Ethephon (Rhone-Poulenc, 2.4% w/w), phosphoric acid (2.4% w/w), MKP (66% w/w), DKP (20% w/w), and humic Acid (1.2% w/w) and the remainder was based on the coating formulation.            **FRF—fruit retention force, measured by a portable digital FRF apparatus.            Note:            FRF value of untreated olive trees was the same as trees sprayed with non-coated product (350 gr).            The same materials used for Ethephon recovery analysis was sprayed (3% w/w) by a commercial sprayer on 20 ‘Barnea’ olive trees for each treatment. The values of FRF tests are mean of 20 replicates for each tree.