Growth regulation process
United States Patent 1 Fritz et al.  
 [451 Apr. 22, 1975 1 GROWTH REGULATION PROCESS [75] Inventors: Charles D. Fritz. Philadelphia; Wilbur F. Evans, Springhouse; Anson R. Cooke, Horsham. all of Pa.  
 Related U.S. Application Data [63] Continuation of Ser. No. 869386. Oct. 24. 1969. which is a continuation-in-part of Ser. No. 693.698. Dec. 27. I967. abandoned. which is a continuation-in-part of Ser. No. 617.860. Feb. 23. 1967. abandoned.  
 Primary E.\&#39;uminer.lames 0. Thomas, Jr. Attorney, Agenl, or FirmCaesar, Revise. Bernstein &amp; Cohen [57] ABSTRACT A growth regulation process involving certain phos&#39; phonic acid compounds having the general formula:  
 The growth regulation process of the present invention relates mainly. though not entirely. to the inducement of an ethylene response or ethylene-type response in plants and part thereof including. but not limited to, stems. roots. leaves. flowers. buds. and harvested as well as unharvested fruit.  
 The method of the present invention produces a wide variety of plant growth responses including:  
 1. Increasing yields 2. Auxin activity 3. Inhibition of terminal growth. control of apical dominance, increase in branching and increase in tillering 4. Changing bi chemical composition of plant or portions thereof 5. Abscission of foliage. flowers and fruit 6. Hastening ripening and color promotion in fruit 7. Increasing flowering and fruiting 8. Abortion or inhibition of flowering and seed development 9. Prevention of lodging l0. Stimulation of seed germination and breaking of dormancy l 1. Resistance to freeze injury 12. Hormone or epinasty effects 13. Interaction with other growth regulators l4. Interaction with herbicides 15. Disease resistance.  
  65 Claims, No Drawings GROWTH REGULATION PROCESS This application is a continuation of U.S. application Ser. No. 869,386, filed Oct. 24. 1969, which is a Continuation-ln-Part application based on prior co-pending Application Ser. No. 693,698. filed Dec. 27. 1967 and entitled Phosphonic Compound Growth Regulation Process which in turn was a Continuation-ln-Part application based on prior copending application Ser. No. 617,860, filed Feb. 23, 1967 and entitled Growth Regulation Process Utilizing Phosphonic Compounds, both now abandoned.  
  The present invention relates to the use of certain phosphonic acid compounds in order to induce growth regulating responses exemplified. but not necessarily limited to ethylene response or ethylene-type responses.  
  The induction of an ethylene response in plant growth by other means has been known for some time in the art. See Plant Biochemistry by James Bonner and J. E. Varner (1965). pages 641 to 664.  
  A fairly well known ethylene response is the use of gaseous ethylene in the ripening of bananas which has been carried out on a commercial scale for many years. It is also known to employ ethylene in essentially gaseous form to stimulate flower initiation in pineapples. See Hormonal Control of Plant Growth&#34; by N. S. Parihar (1964), pages 69 to 79. Here, ethylene was applied on a commercial scale using cumbersome equipment to dreneh the pineapple plants with ethylene saturated liquid. Similar, but less powerful effects on plant tissues have been caused by other unsaturated hydrocarbic gases.  
  The mechanism by which ethylene and the other gases affect the growth cycle of plants is far from fully understood, but it is clear that they do play a role. It will be seen that the phosphonic acid compounds and derivatives used to practice the present invention contain in their structures molecular configurations which are capable of breaking down into ethylene or like compounds although there is no intention to limit the present invention to this theory or any other theory.  
  The use of certain other phosphonate compounds in the agricultural art is known for herbicidal purposes asset forth in U.S. Pat. Nos. 2,9 ,0l4 and 3,223,514. However, it will be seen that the compounds disclosed in the aforesaid two patents do not produce the growth regulating responses for ethylene-type response of the present invention.  
  Instead, the present invention involves the inducement ofa plant regulating response or an ethylene-type response through the application of compounds at the plant site having the following generic formula:  
 where R is selected from this group consisting of haloethyl and phosphono-ethyl; and  
 R and R are selected from the group consisting of l. Chlorine atom and a hydroxy group; 2. The group -OR,, and the group O-CH R where each R is one member of the group of unsubstituted aryl, substituted aryl and heteroeyclic groups;  
 (R4 and R are each connected to the phosphorous R atom by a separate single 6 bond) where one of R and R is O-- and the other is selected from the group of O-; -OCH COO and CONH and R represents a cyclic group selected from the group consisting of benzene, substituted benzene, heterocyclic ring and substituted heterocyclic ring;  
 5. One of R and R is -OR and the other is wherein each R is the same or different and is selected from the group of hydrogen, unsubstituted alkyl, substituted alkyl, unsubstituted aryl, substituted aryl and a heterocycle group, and wherein R is as defined hereinbefore.  
  Reference is hereby made to the following prior copending applications, the disclosures of which are hereby incorporated by reference:  
 1. Application Ser. No. 617,860 Filed: Feb. 23, 1967, now abandoned Inventors: Charles D. Fritz and Wilbur F. Evans Title: Growth Regulation Process Utilizing Phosphonic Compounds 2. Applications Ser. No. 617,820, now U.S. Pat. No. 3,531,549 and Ser. No. 617,819 now U.S. Pat. No. 3,551,528 Both Filed: Feb. 23, 1967 Inventor: David Randall Title of Both: Phosphonic Acid Esters and Method for Their Preparation Assignce: General Aniline and Film Corporation The foregoing applications specified hereinabove basically disclose preparation techniques for the compounds utilized in the method of the present invention.  
  Where the term halo&#34; is used, it is to be understood that this term means the familiar halogens, i.e., fluorine, chlorine, bromine and iodine, so long as an operative growth regulation compound is obtained.  
  With reference to the general formula utilized in the method of the present invention, preferred groups for substituent R are haloethyl, forexample, 2-chloroethyl, Z-bromoethyl and 2-iodoethyl. Preferred half-esters of the phosphonic acid moiety include the 2-ehloroethyl mono-ester and the o-hydroxyphenyl mono-ester. Preferred diesters include the diphenyl and the bis (2-oxo-l-pyrrolidinyl-methyl) esters and as mixed esters, the 2-hydroxyphenyl ester with an alkyl or alkenyl or aryl radical for example, ethyl, isopropyl, propynyl, butyl, octyl, hexadecyl or phenyl radicals. Aryl groups are preferably monocyclic, and bior polycyclic aryl groups may be used provided a group to render them soluble (e.g.. a sulphonate group), is present thereon.  
  The term *alkyl&#34; as used herein is intended to include the analogous compounds which have the same growth promotion properties and includes for example cycloalkyl groups, sucy as cyclohexyl. Preferred alkyl groups are those having up to preferably 18 carbon atoms because above this range. the derivatives are less soluble.  
  Preferred cyclic esters include those formed with pyrocatechol or monoor polyhalopyrocatechol derivatives, for example 4-chloropyrocatechol or tetrachloropyrocatechol; with salicyclic acid, with saligen; and with 2,3-pyridined. Another preferred derivative is the acid chloride.  
  It will be seen that the preferred phosphonie derivative to be used in connection with the present invention is 2-chloroethyl-phosphonic acid or its immediate derivatives as will be discussed in more detail hereinafter.  
  The phosphonic acid compound used in the process of the present invention have been found to display a wide variety of plant growth regulating properties or ethylenetype responses, depending upon the concentration used, the formulation employed and the type of plant species treated. While the compounds used in the present invention may be regarded as achieving an ethylene response or an ethylenetype response, the present invention is not necessarily limited thereto since it is recognized that certain growth regulating responses achieved through the practice of the present invention may not be regarded as being technically traditional or known or to be discovered ethylene responses or even ethylenetype responses. Hence, it is preferred to regard the results achieved in the practice of the present invention as growth regulating responses. I  
  In view of the foregoing, it can be seen that the term method for regulating plant growth&#34; or the term growth regulation process&#34; or the use of the words growth regulation or other terms using the word regulate as used in the specification and in the claims mean a variety of plant responses which attempt to improve some characteristic of the plant as distinguished from herbicidal action, the intention of which is to destroy or stunt a growth of a plant. For this reason the compounds used in the practice of this invention are used in amounts which are non-phytotoxic with respect to the plant being treated.  
  Nevertheless, the phosphonic acid derivatives connected with the present invention can sometimes be used in a herbicidal context, for instance, to stimulate the growth of dormant rhizomes in order to make such rhizomes more susceptible to a herbicide. However, even here the phosphonic acid derivatives used in the present invention are not themselves in any practical sense herbicides since they promote the growth of the unwanted plant or otherwise make it vary susceptible to a true herbicide. Thus, the present invention can be carried out in conjunction with or in the presence of other compounds or mixtures which are herbicides.  
  By virtue of the practice of the present invention a wide variety of plant growth responses, generally ethylene responses or ethylene-type responses have been achieved, including the following:  
 1. Increasing yields 2. Auxin activity 3. Inhibition of terminal growth, control of apical dominance, increase in branching and increase in tillering 4. Changing bio-chemical compositions of plant 5. Abscission of foliage, flowers and fruit 6. Hastening ripening and color promotion in fruit 7. Increasing flowering and fruiting 8. Abortion or inhibition of flowering and seed development 9. Prevention of lodging 10. Stimulation of seed germination and breaking of dormancy l 1. Resistance to freeze injury [2. Hormone or epinasty effects 13. Interactions with other growth regulators l4. Interactions with herbicides 15. Disease resistance It is intended that as used in the appended claims the term method for regulating plant growth&#34; or method for inducing an ethylene response or method of inducing an ethylene-type response means the achievement of any of the aforementioned fifteen categories of response as well as any other modification of plant, seed, fruit, vegetable (whether the fruit or vegetable is unharvested or have been harvested) so long as the net result is to increase growth or benefit any property of the plant, seed, fruit or vegetable as distinguished from herbicidal action (unless the present invention is practiced in conjunction with or in the presence of a herbicide). The term fruit as used herein and in the appended claims is to be understood as meaning anything of economic value that is produced by the plant.  
 Certain preliminary details connected with the foregoing fifteen categories should make for a better appreciation of the invention.  
 1. INCREASING YIELDS The phosphonic acid derivatives are capable of increasing yields of many plants, including, but not limited to small grains, particularly oats (Avena sativa), wheat (Triticum aestivum), and barley (Hordem spp.); and of increasing yields of other types of plants, such as beans and of cotton (Gossypium hirsurum);  
 2. AUXIN ACTIVITY When applied for instance as a lanolin paste, to one side of a decapitated sunflower hypocotyl the phosphonic acid derivatives are capable of inducing bending of the hypocotyl away from the side of the application; they are also capable of inducing sprouting of underground rhizomes of monocotyledonous and dicotyledonous plants; of causing cell proliferation; and of inducing rooting, as evidenced by the production of large numbers of root primordia over the entire stem length of tomato plants (Lycopersicon esculenlum) after these have been sprayed with an aqueous solution thereof this type of response makes it possible to root cuttings either when taken from treated plants or after treatment of their cut ends.  
  3. INHIBITION OF TERMINAL GROWTH, CONTROL OF APICAL DOMINANCE, INCREASE IN BRANCHING, AND INCREASE IN TILLERING These types of plants growth response can be produced on a variety of plant species when they are treated with the phosphonic acid derivatives including privet (Ligustrum ovalifolium), blueberry (Vaccinum corymhosum), azalea (Rhododendron ohrusum), soybeans (Glycine mas.), snapbeans (Plwseolus vulgaris), tomatoes (Lycopersion esculenrum), alligator weed (Alternanthua philoxeroides) and monocotyledons such as rice (Oryza sativa), johnsongrass (Sorghum halopense) and wild oats (Avena fatua). This type of response can also be of value in the control of roadside grasses. It has been suggested that the removal of the lead bud (e.g.. by pinching) should allow growth of auxiliary buds; but it is generally found that on removal of the lead bud one of the auxiliary buds takes over the activity and dominance of the lead bud. The use of the phosphonic acid derivatives, however, usually retards the activity of the lead bud for a while but then later restores the lead bud to normal growth, with production of normal flowers and normal fruit; and thus one avoids the permanent loss of buds inevitably associated with pinching. However. some plant species respond differently when treated with the phosphonic acid derivatives for control of apical dominance growth inhibition may extend to include not only the lead bud but also lateral buds along the stem. Examples of such plants are tobacco (Nicotiana tabacum) and Chrysanthemum (Chrysanthemum sp.) this type of response is useful for preventing sucker growth from lateral buds on tobacco.  
 4. CHANGING BIOCHEMICAL COMPOSITION OF PLANT The phosphonic acid derivatives are capable of measurably increasing the leaf area relative to the stem area in many plants, and the increased ratio of leaves to stem results in an increase in total protein on a per plant basis, and modification of the protein, carbohydrate, fat, nicotine and sugar within the treated plant.  
 5. ABSCISSION OF FOLIAGE, FLOWERS AND FRUIT The phosphonic acid derivatives have been found to accelerate abscission of mature foliage on both perennial and annual plant species. They are for instance quite active as defoliants on cotton, and defoliation properties have also been observed in other plant species such as roses, privet, apples, citrus, and brussel sprouts once the leaves have attained a mature state. Abscission of flowers and/or fruit following application of the phosphonic acid derivatives has been observed on a variety of plant species, including apples (Malus domestica), pears (Pyrus communis), cherries (Prunus avium), pecans (Carva illinoensis), grapes (Vitis vinifera), olives (Olen europaea), coffee (Coffea arahica) and snapbeans (Phaseolus vulgaris) these abscission responses can be used to regulate flower production and as an aid in harvesting fruit.  
 6. HASTENING RIPENING AND COLOR PROMOTION IN FRUIT The phosphonic acid derivatives have been shown to be capable of hastening the ripening of fruit (picked or unpicked) from a number of plant species, such as apples Malus domestica), pears (Pyrus communis), cherries (Primus avium), bananas and pineapples (Ananas comosus); and of removing the green color from harvestable fruit such as tomatoes (Lycopersicon esculentum) and regreened citrus such as oranges (Citrus sinensis) and lemons (Citrus limon).  
 7. INCREASING FLOWERING AND FRUITING Suitably applied. the phosphonic acid derivatives are capable of increasing flowering and fruiting in a number of economic crops, such as soybeans (Glycine max), snapbeans (Phaseolus vulgaris). kidney beans (Phaseolus vulgaris) and zinnias (Zinnia elegans).  
 8. ABORTION OR INHIBITION OF FLOWERING AND SEED DEVELOPMENT Suitably applied, the phosphonic acid derivatives will inhibit flowering and/or abort seed development, for example in johnson grass (Sorghum lzalepense).  
 9. PREVENTION OF LODGING 10. STIMULATION OF SEED GERMINATION AND BREAKING OF DORMANCY The phosphonic acid derivatives have been shown to stimulate the germination of for instance lettuce seed and to terminate the dormancy of tubers such as seed potatoes.  
 1 l. RESISTANCE TO FREEZE INJURY The phosphonic acid derivatives appear to increase the hardiness of various plant species, such as for example. lima beans (Phaseolus vulgaris).  
 l2. HORMONE OR EPINASTY EFFECTS The phosphonic acid derivatives have been shown to produce hormone or epinasty effects upon various plants, including notably tomatoes (Lycopersicon esculentum).  
  l3. INTERACTIONS WITH OTHER GROWTH REGULATORS The phosphonic acid derivatives may of course be used in conjunction with other plant growth regulators. such as maleic hydrazide, N-dimethyl-amino-succinic acid, gibberellic acid and naphthalene acetic acid, and interact therewith producing synergistic or antagonistic responses in various plants.  
 14. INTERACTIONS WITH HERBICIDES While the phosphonic acid derivatives seem to have essentially no phtyo-toxic activity of their own, they may be used in their capacity as plant growth regulators in conjunction with herbicides, for instance with aminotriazole in the herbicidal control of johnson grass (Sorghum halepense).  
 15. DISEASE RESISTANCE Disease resistance makes tissue resistant to invasion by plant pathogens by influencing the enzyme and plant processes which regulate growth nature disease immunity.  
  As previously stated, the phosphonic acid compounds usable in the practice of the present invention fall within the general formula:  
  Specific phosphonic derivatives usable in the method for&#39;regulating plant growth falling within the scope of the present invention include:  
 1. The bis(acid chloride) phosphonic acid.  
 2. The pyrocatechol cyclic ester of 2-chloroethylphosphonic acid.  
 3. The 4-chloropyrocatechol 2-chloroethylphosphonic acid.  
 4. The mixed ethyl and 2-hydroxyphenyl diester of 2-chloroethyl-phosphonic acid.  
 5. The mixed butyl and 2-hydroxyphenyl diester of 2-chloroethyl-phosphonic acid.  
 6. The mixed propynyl and 2-hydroxyphenyl diester of 2-chloroethyl-phosphonic acid.  
 7. The 2-chlorocthyl monoester of 2-chloroethylphosphonic acid.  
 8. 2-bromoethyl-phosphonic acid.  
 9. The bis (phenyl)-ester of Z-chloroethylphosphonic acid.  
 H). The tetrachloropyrocatcchol cyclic ester of 2-chloroethyl-phosphonic acid.  
 1 l. Z-iodoethyl-phosphonic acid.  
 l2. The saligen cyclic ester of 2-chloroethylphosphonic acid.  
 13. Salicyclic acid cyclic ester of 2-chloroethylphosphonic acid. I  
 14. Phosphonoethylsphosphonic acid.  
 15. Phosphonoethylthioethyl-phosphonic acid.  
 16. The 3-hydroxyphenyl monoester of 2-chloroethyl-phosphonic acid (which exists in polymeric form).  
 l7. The bist2-oxo-pyrrolidinylmethyl) 2-chloroethyl-phosphonic acid.  
 l8. The o-hydroxyphenyl monoester of 2-chloroethyl-phosphonic acid.  
 l9. The mixed isopropyl and 2-hydroxyphenyl diester of 2-chloroethyl-phosphonic acid.  
 20. 2-fluoroethyl-phosphonic acid.  
 21 The mixed octyl and 2-hydroxyphenyl diester of 2-chloroethyl-phosphonic acid.  
 22. The mixed hexadecyl and 2-hydroxyphenyl diester of 2-chloroethyl-phosphonic acid.  
 23. The mixed tridecyl and Z-hydroxyphenyl diester of 2-chloroethyl-phosphonic acid.  
 24. The anhydride of 2-chloroethyl-phosphonic acid.  
 25. 2-chloroethyl-phosphonic acid.  
 26. 2-chloroethyl-butylester, 2-hydroxyphenylester of phosphonic acid.  
 27. 2-chloroethyl-2-chloroethylester of phosphonic acid.  
  Other useful phosphonic derivatives of this invention are salicyclic acid cyclic ester of phosphonamidic acid, the mixed phenyl and 2-hydroxyphenyl diester of 2-chloroethylphosphonic acid, 2-chloroethyl-dichlorophosphine, the his (pentachlorophenyl) ester of 2-chloroethyl-phosphonic acid; 2-chloropropylphosphonic acid, 2-phenylthioethyl-phosphonic acid, the 2,3-pyridinedio cyclic ester of 2-chloroethylphosphonic acid, 2-chloroethyl-thiophosphonic acid (2- bromo, 2-fluoro and 2-iodo) and 2-chloroethyl- 2,3.dibromo-4-hydroxy-2-butyenyl ester polymer. Salts of the phosphonic derivatives of this invention may be of Z-chloroethylcyclic ester of ester of used. Examples of such salts include the sodium, aluminum, zine, potassium and lithium salts.  
  It is known that certain of the hereinabove mentioned phosphonic compounds will polymerize, but such compounds are usable to practice the present invention whether in monomeric or polymeric form so long effective growth regulation is achieved.  
  The phosphonic derivatives used in the method of the present invention are soluble in varying degrees in water and so they can be applied to plants in aqueous solutions composed wholly or partially of water. Partial solutions include those formed of water and. for instance. acetone or methyl ethyl ketone. Any liquid medium may be used provided that it is not toxic to the plant. Where any particular derivative is less watersoluble, it may be solubilized by the use of co-solvents and the like. However, an example of a phosphonic derivative which can be applied in organic solution is the bis (acid-chloride) of 2-chloroethyl-phosphonic acid. Other media, including solids, like talc, will occur to those skilled in the art.  
  It will be seen from all of the foregoing that the plant growth regulating activity of the phosphonic acid derivatives of the present invention resides in the 0 ll 0- P/ sired plant growth regulating activities. The phosphonic derivatives used in the practice of the present invention will include both compounds which hydrolyze very readily as well as compounds which hydrolyze only with difficulty, perhaps owing to steric hindrance.  
  Moreover, there are compounds which in the laboratory can be hydrolyzed only with difficulty, yetwhich apparently can be metabolized by the plant and hydrolyzed by its enzymatic systems quite readily.  
  The phosphonic acid derivatives employed in the practice of the present invention should normally be compounds known to be readily hydrolyzable, either in the laboratory or in the plant under treatment. The ability of any phosphonic derivative to be used in the practice of the present invention is initially determined in the greenhouse by testing such compound to determine their powers to produce epinasty in tomato plants, using the routine standard methods as set forth in the previously mentioned Bonner and Varner text.  
  It will be further seen that many of the phosphonic derivatives used in the practice of the present invention conform to the following general formula:  
 in which one ofx or y is 0 and the other is 0 or 1; R is haloethyl or phosphono-ethyl; R is a hydrogen atom or a substituted orunsubstituted phenyl group; and R is a hydrogen atom or a substituted or unsubstituted phenyl group or a halogen-substituted or unsubstituted, saturated or unsaturated hydrocarbon chain containing from 2 to 12 carbon atoms.  
  It can be seen from the foregoing that the dialkyl esters have been purposely excluded from the scope of compounds usable to practice the present invention because such dialkyl esters have not achieved any significant growth regulating results when used in the practice of the present invention. However, aryl diesters or even mixed alkyl and aryl diesters or even cyclo esters have proved to be effective in the growth regulating processes of the present invention.  
  It is preferred that the compounds falling within the scope of R in the general formula of compounds usable in the practice of the present invention be halo ethyl, with 2-chloroethylphosphonic acid embodying the preferred compound. Of course, R can also be phosphoneethyl as exemplified by a -PO(Y)Z group; wherein Y is a chlorine atom or an OR group; R is a hydrogen atom or a saltforming cation or a substituted or unsubstituted aryl, arylmethylene, heterocyclyl or heterocyclylmethylene group, or the X(CH .PO(Z) group wherein Z is defined as (but not necessarily identical to) Y or Z is a substituted or unsubstituted. saturated or unsaturated hydrocarbon chain wherein R and Z together form an O-d O.CH C0.0-- or Co.NH-- linkage, wherein (1) represents a divalent, substituted or unsubstituted benzene or heterocyclic ring.  
  It is to be understood that the term aryl refers especially to monocyclic aryl groups, whether substituted or not, but may extend also to bicyclic and polycyclic aryl groups provided that they hear one or more substituents capable of imparting water-solubility to the compound as a whole, such as sulphonate groups.  
  The substituted or unsubstituted, saturated or unsaturated hydrocarbon chains present in the phosphonic derivatives usable in the practice of the present invention, will normally be lower alkyl or cyclo-alkyl groups, such as ethyl, isopropyl, butyl and cyclohexyl groups. The hydrocarbon grouping should range from to to 18 carbon atoms, since above 18 carbon atoms it has been found that the water-solubility of the compound as a whole decreases undesirably,  
  As will be demonstrated in connection with certain examples in this specification, compounds used in the process of the present invention have been quite effective in regulating plant growth and development in connection with a wide variety of plant species at various concentrations of active phosphonic acid compounds. Amounts of as little as 0.1 lb./acre of compounds falling under the generic definition of the formula:  
 have been observed to cause marked increase in branching and lateral growth of several varieties of tomato plants. Moreover, compounds used in the process of this invention, when employed at concentrations ranging from 0.1 lb. to 16 lbs/acre (or from to 48,000 ppm) have demonstrated pronounced modifications in plant growth, including, but not limited to, increased fruiting and flowering and induction of sprouting as compared with similar untreated plants. The phosphonic derivatives may be stabilized against water or moisture incorporating an acid therein to insure that the pH is not greater than five, with the term acid&#34; being used to cover any material which will impart the desired pH value. Also, an appropriate buffering agent can be used to maintain the pH of the composition at five or less.  
  The precise amount of phosphonic acid compound will depend upon the particular plant species being treated. An amount of from about 0.1 lb. to as much as 25 to 30 lbs/acre of these compounds, when applied to plants, will result in varying plant responses depending upon the total amount of compound used, as well as the particular plant species which is being treated. Of course. the amount of phosphosphonic acid compound should be non-phytotoxic with respect to the plant being treated.  
  It is preferred that the compounds used in the process of the present invention be applied at rates of /2 to 4 lbs/acre in aqueous solution and that the application rate in terms of total volume varies from about 1 to gallons per acre.  
  The phosphonic acid compounds used in the process of this invention are generally soluble in &#39;water. In instances where these compounds are not appreciably water soluble, it has been found that contact with water frequently causes sufficient hydrolysis to result in a soluble product thereby obviating the necessity of utilizing sophisticated formulations containing surfactants, dispersing agents, extenders, etc. However, if desired, the compounds used in the process of this invention may be absorbed onto solid carriers such as vermiculite, attaclay, talc and the like for application via agranular vehicle. Application of water thin solutions or solids is accomplished using conventional equipment that is well known in the art.  
  Although the preferred method of application of the compounds used in the process of this invention is directly to the foliage and stems of plants, it has been found that such compounds may be applied to the soil in which the plants are growing, and that such compounds will be rootabsorbed to a sufficient extent so as to result in plant responses in accordance with the teachings of this invention.  
  The compounds used in the process of the present invention are preferably applied to growing plants as set forth in many of the examples in this specification. However, under certain circumstances, the compounds used in the process of the present invention are active in seed treatment, for instance, lettuce seeds and oat seeds.  
  Certain compounds which are usable in the process of the present invention may be prepared in accordance with said concurrently filed Application Serial No. 617,820 entitled Phosphonie Acid Esters and the Method for Their Preparation, (Case 1752) the entire disclosure of which is hereby incorporated by reference, now US. Pat. No. 3,531,541. The preparation techniques set forth in said copending application may be used to prepare other compounds falling within the scope of the present invention, and the preparation techniques of such compounds will readily occur to those skilled in the art. For instance, the preparation techniques of said copending application deal essentially with the situation in which R is haloalkyl but it should be quite clear that the same techniques may be utilized&#39;with the starting materials containing the desired R substituent.  
  As further set forth in said copending application, certain of the compounds falling within the scope of the present invention may be described as catechol or sub- I stituted catechol half esters of 2-haloethylphosphonic acid.  
  The hydrolysis of the cyclic ester, unlike hydroylsis of other phosphonate esters, proceeds rapidly at about room temperature with evolution of heat and consequently, there is no need to employ elevated temperatures, although temperatures up to about 60C. may be employed. Temperatures higher than about 60C. should be avoided since the phosphonic acid half esters of the invention hydrolyse at such temperatures.  
  The catechol cyclic esters employed as a starting material for producing the compounds used in the process of the invention may be prepared in accordance with the process disclosed by Kabaehnik et al, Izvest, Akak Nauk SSSP, o.k.h.n. 1947, 97 (Chem. Abstracts 42, 4132c) both hereby incorporated by reference. Thus, as disclosed by Kabachnik et al, the starting materials for producing the compounds used in the process of the invention are produced by reacting a 2-haloethylphosphonyl chloride with catechol or a substituted catechol, e.g., 2-chloroethylphosphonyl chloride is heated with catechol at l50l 60C. to produce the catechol cyclic ester of 2chloroethylphosphonic acid. Similarly, a sub stituted catechol, for example, a halo catechol, produced by adding chlorine or bromine to an acetic acid solution of catechol, may be reacted with 2-chloroethylphosphonyl chloride to produce the corresponding cyclic ester. As a further alternative, the catechol cyclic ester of 2 ehloroethylphosphonic acid may be treated to effect substitution thereof. Thus, for example. an O-dichlorobenzene solution of the catechol cyclic ester of 2-chloroethylphosphonic acid may be warmed with an excess of sulfonyl chloride to produce a tetrachloro substitute catechol cyclic ester of 2-chloroethylphosphonic acid.  
  The following examples are illustrative of methods of preparing compounds that are used in the process of the present invention.  
 EXAMPLE A 4.4 parts of the cyclic ester of pyrocateehol with 2-chloro-ethylphosphonic acid were added to 44 parts of water, with stirring at 27C. An exothermic heat of hydrolysis was noted in a 3 temperature rise to 30C. The slightly milky solution was heated briefly to 50C. and water removed at this temperature in a slash evaporator at a vacuum of about 30mm. 4.8 parts of the catechol half ester of 2-chloroethyl-phosphonic acid was recovered as a colorless liquid. The phosphonic acid half ester was soluble in water, had a titration curve typical of a strong monobasic acid and showed no tendency to hydrolyze in aqueous solutions at room temperature, even after standing for 3 weeks. The phosphonic acid half ester hydrolyzes rapidly in boiling water.  
 EXAMPLE B 3.4 parts of the cyclic ester of pyrocateehol with 2-chloro-ethylphosphonic acid were added to 0.28 part of water (the stoiciometric amount of water required for hydrolysis) at 30C. and there was a temperature rise to 80C. The mixture was cooled and 3.6 parts of the catechol half ester of 2-chloroethylphosphonic acid was recovered as a viscous liquid.  
  The above procedure is also employed to produce the catechol half ester of 2-brom0ethylphosphonic acid.  
  In order to illustrate the surprising results flowing from this invention there are presented below a series of experimental test results which are presented solely by way of illustration and are in no way intended to be construed in any way limiting the scope of this invention.  
  It has been theorized that with the practice of the present invention the phosphonic derivatives break down outside the plant while still in the aqueous solution in which they were applied, and that the ethylene thus released is assimilated by the plant in gaseous form. However, this seems unlikely since even when stabilized against hydrolytic breakdown, the phosphonic derivatives will to a greater or lesser extent exert plant growth regulating activity when applied to plants, as demonstrated for instance by the epinasty tests upon tomato plants. 7  
  It is therefore theorized that the phosphonic derivatives used in the practice of the present invention exert their growth regulating activity, at least in the great majority of cases, by assimilation into the metabolic system of the plant. Indeed, analytical investigations have shown that immediately following application to the plant, residues of these phosphonic derivatives are for a limited period of time to be found in plant tissues. Other investigations have shown that in many plants some time after the application of the phosphonic derivatives, the plant tissues contain detectable amounts of ethylene.  
  From the foregoing it can be concluded that the phosphonic derivatives are broken down within plant tissue to release ethylene, and that the ethylene thus released exerts its normal functions. One conclusion from this is that the ethylene causes the artificial acceleration of the plants natural life cycle, but it seems that the present invention does more than this because the plant growth regulating effects of the present invention occur to a greater degree than in nature. Indeed, it appears that the amount of ethylene released within the plant tissue is greater than that which could be derived from the phosphonic derivatives assimilated by the plant tissues. If this is correct, then it would seem to follow that the assimilation of the phosphonic derivatives by the plant tissues may trigger-off the enzymatic or other systems within the plant which in themselves generate ethylene.  
  The foregoing explanation is presented in an effort to promote a better understanding of the present invention, but since other investigations are still being carried out, it is quite possible that additional observations may necessitate a revision or even an abandonment of such a theory. In recognition of this it is again repeated that the reasons why the present invention has proved to be so successful have not as yet been determined with certainty, and this specification is to be so understood.  
  There will now be presented a large number of examples which primarily involve 2-chloroethylphosphonic acid as applied under a variety of application rates and concentrations to a wide variety of plant, seed, vegetable and fruit species. The other 33 compounds specifically disclosed hereinabove have shown sufficiently positive results in tomato epinasty tests as to warrant the conclusion that such compounds can be used in the flowers and late flower set will increase the number of ripe fruit in proportion to the amount of over-ripe fruit produced from early flower set and the percent of green fruit at harvest in relation to late flower set. This iompougid, such other compound sp gi reduces the amount of sorting required to separate t l i P l t p -f lf p i mt e over-ripe and green fruit from desirable ripe fruit at ma 0 p an epmas y es or a so s ow p ant growt harvest regulating characteristics of one or more of the other fourteen categories set forth hereinabove. EXAMPLE 2 The followin exam les are illustrative of the wide i range of plant siecies a be Subectcd to the lam \Tlllb evaluation demonstrates the use of a compound of the invention for inducing earlier flowering and ingrowth regulating process of the present invention, Cream] flower numberq using 2-chloroethylphosphonic acid, but in view of the i y fact that the other thirty-three compounds did show Tomato (L).(0IwrsIwn plants were hprilycd with positive results in the tomaw p epinusty test and aqueous solutions of 2-chloroethylphosphomc acid in as further confirmed in some additional examples set the ci to first true loaf stage The results are reforth hereinafter, it has been concluded that all 34 corde be phosphonic compounds as well as other compounds falling within the scope of the appended claims can be used. the pf of the present invention Treatment Number of open blossoms per No. of flowers it IS recognized that it is a virtually impossible task to rate plant 4 weeks after treatment 4 weeks after try to test even 2-chloroethylphosphonic acid on every existing plant species. However, as will be seen from an Comm] I 4 evaluation of more than one hundred examples to fol- 250 4 7 low, the Applicants have subjected 2-chloroethylphos- 2 2 phonic acid to tests involving an extremely wide variety of plant species. Nevertheless. there is no intention that the invention be limited to these compounds as in the Use of a compound of the invention to increase the future, workers in the art may find the process of the nurabcr of flower per mm and to increase carl&#39; present invention to be an effective growth regulant on n p 1 y other plants form blossom opening for fertilization is of economic However, it should readily occur to one skilled in the particularly Y with a 1 grqwmg art that the recognition 0f improved results using the Earlier flower pollination and uniform fruit set Wlll rccompounds of the present invention in connection with Sult camel harvest ty. Further, increased other plants, seeds, fruits and vegetables not specififlower numbcrh offer the potemml for mcreasmg crop cally set forth herein is readily within the abilities of W one skilled in the art. EXAMPLE 3 EXAMPLE l This evaluation demonstrates the use of a compound This evaluation demonstrates the use of a compound 40 of the invention as a Chemical ripening for accelof the invention for induction of flower abscission. eratlo&#34; and Concentration of harvest Tomato (Lyco ersicon sp.) plants were sprayed with T mato (Ly vp rsiwn p plant wer reated with aqueous solutions of 2-chloroethylphosphonic acid aqueous solutions of 2-chloroethylphosphonic acid during flowering. The results are recorded below. prior to harvest. The results are recorded below.  
  71 Flower ahscission 71 Yield of red ripe fruit Treatment Days after treatment Days after treatment rate ppm 7 14 Treatment Comm 0 0 rate ppm 7 14 21 24 2; Control 35 53 71 83 m0 68 250 51 69 x7 600 5 96 500 64 82 89 1000 100 r00 89 5000 72 90 Use of a compound of the invention was effective for inducing abscission of flower buds and flowers. Rates Acceleranon of harvebt matumy of 50 to 300 ppm of z chloroethylphosphonic acid all treatments. Concentration ofred ripe fruitis ofecowere most effective in abscising unpollinated flowers 6O nomlc v alue for mcfeasmg crop Y x of once&#39;over whereas those not abscised were pollinated at the time mechanical hal&#39;vestmg f for a reduction the number of treatment Rates of 600 and 1,000 ppm abscised of harvesting times required to collect the tomato crop both pollinated and unpollinated flowers and buds. y hand P Treatment rates of 300 to 1,000 ppm caused a tempo- Tl&#39;eatfnents&#39;of li f f 5,000 Plf mduced rary dwarfing of vegetative growth and leaf epinasty. defoliation. Defoliatron [8 important in late production The control of flowering on tomatoes through flower abscission is of economic value in relation to concentration of harvest maturity. Elimination of early set areas in order to provide exposure of the fruit to air and sunlight&#39;thereby reducing the incidence of disease and delayed ripening.  
 EXAMPLE 4 Treatment &#39;71 Red ripe fruit in days after treatment rate ppm 2 5 8 l Tomatoes ripened more rapidly and uniformly after treatment as a postharvest dip or spray with a compound of the invention. Very immature as well as nature green fruit were ripened. Significant color improvement was obtained in two days following treatment with 5.000 and 10,000 ppm. Acceleration of ripening was in proportion to concentration of 2-chloroethylphosphonic acid and internal as well as external red color developed more quickly in treated fruit. Variability in red color from fruit to fruit during the ripening period was markedly reduced in treated fruit. The greatest acceleration of ripening was observed when immature green or mature green fruit were dipped in aqueous solutions of 2-chloroethylphosphonic acid for 2 minutes and held at a temperature of 70F. Fruit which were pink or red in color were not accelerated to the same extent as immature or green mature fruit. however, uniformity of ripening and color development was increased.  
  Fruit ripening after treatment with a compound of the invention appears to be normal in every respect. Changes in color. pH, and firmness were similar to those occurring in untreated fruit, however. these changes occurred more rapdly and uniformly. Further, it appears that use of a compound of the invention as a chemical ripening agent will accelerate and induce the normal sequence of events occurring during ripening.  
  Treatment with a compound of the invention is of economic value particularly when tomatoes are harvested green in the Southern States during the winter and shipped North where they are held in ripening rooms until mature. Post-harvest treatment will reduce the time in storage and reduce costly sorting of tomatoes in ripening rooms as a result of better uniformity and acceleration of ripening. Treatment could be applied to detached fruit before shipment, with the fruit ripening enroute to market, thereby eliminating the need for ripening rooms.  
 EXAMPLE This evaluation demonstrates the use of a compound of the invention for concentration of fruit maturity.  
  Tomato (Lycopersicon sp.) plants were sprayed with aqueous solutions of 2-chloroethylphosphonic acid two weeks prior to harvest. The results are recorded below.  
  As the concentration of 2-chloroethylphosphonic acid increased the proportion of green fruit decreased with a corresponding increase in red ripe fruit. The percentage of over-ripe fruit was unaffected. Rates of 5,000 and 10,000 ppm caused some leaf chlorosis and epinasty of foliage but did not impair fruit appearance in any respect. Internal as well as external red color was increased in treated fruit.  
  Use of a compound of the invention in the field prior to harvest is of economic value particularly for mechanical once-over harvest techniques since chemical treatment concentrates red ripe fruit maturity and thereby increases the proportion of ripe fruit recovered during a single harvest. Not only is the yield of usable red ripe fruit increased following a field application with a compound of the invention but there is also a saving in labor required to sort mechanical harvest green fruit. Treated fruit does not become over-ripe sooner than normal since the chemical accelerates green fruit to a greater extent than pink or red fruit following treatment.  
 EXAMPLE 6 This evaluation demonstrates the use of a compound of the invention for acceler&#39;ating fruit maturity.  
  Tomato (Lycopersicon sp.) plants were sprayed with aqueous solutions of 2-chloroethylphosphonic acid at various intervals after pollination. The results are recorded below.  
 Treatment Time of application in Days until fruit develrate ppm days after pollination oped full red color Control S5 250 0 49 250 2 48 250 2. 9 &amp; I6 40 250 39 47 500 0 48 500 2 47 500 I4 46 500 39 46 i000 I4 43 I000 39 46 17 EXAMPLE 7 This evaluation demonstrates the use of a compound of the invention for inducing disease resistance.  
  Tomato (Lyn-operation sp.) plants were sprayed with aqueous solutions of 2-chloroethylphosphonic acid alone and with a fungicide just prior to harvest. The results are recorded below.  
 Treatment 7! Anthracnose disease for 2 tomato varieties rate New Yorker New York 903 Control 342 47.0 Z-Chloroethylphosphonic acid at 5000 ppm 3L4 26.6 2ehloroethylphosphomc acid at 5000 ppm Fungicide (l) 4.7 7.4 Fungicide (l) 8.8 14.5  
 ( l) Dit&#39;olataa 4F applied at L2 lbs active per acre Use of a compound of the invention was effective for reducing the incidence of Anthracnose disease. Disease control was further increased when 2-chloroethylphosphonic acid was applied in conjunction with a fungicide such as Difolatan when compared to use of the fungicide alone.  
 EXAMPLE 8 This evaluation shows abscission effects in apple fruit. Apple trees (Malus domestica; variety McIntosh) oftissue. which indicates fruit maturity. The abscission and ripening acceleration demonstrates the effectiveness of the phosphonic derivatives in allowing earlier harvesting.  
 EXAMPLE 9 In another apple abscission Evaluation (Malus domestica: variety Rome Beauty) were sprayed with aqueous solutions of 2-chloroethylphosphonic acid, and the fruit then mechanically harvested 16 days later using a tree shaker (which will remove only those fruit which are loose). The following results were noted:  
  This evaluation again shows the increase in rate of harvesting of fruit on trees treated as opposed to trees untreated.  
  Apple trees (variety Gravenstein) were sprayed (when the fruit were beginning to mature) with aqueous solutions specified below. and the trees and fruit were examined two weeks later. The following results were obtained:  
 Treatment Rate Fruit Fruit Red colour Soluble ppm. drop 7r firmness 7r solids 7r lb/sq. in.-  
 Control l4.3 90.8 ll.8 2-ehloroethyl phosphonic 250 47.5 13.7 98.7 l2.0 acid NAA 250 8 12.5 97.9 11.8  
 were sprayed to run off with aqueous solutions of 2-ehloroethylphosphonic acid just prior to normal fruit harvest. Fruit abscission noted seven and eleven daysafter treatment was as follows:  
 Treatment Z Fruit abscission Maturity Index 7 days l 1 days lhl &#34;/1 maturity pressure increase Control (0 ppm.) 17 38 6.9 0 500 ppm. 66 100 4.1 34 1500 ppm. 85 l()() 4.5 35 4500 ppm. 89 100 4.0 42  
  The results show how early abscission is induced causing the fruit to drop off the tree percent abscission. for example, equals 50 percent fruit drop) and enabling harvesting of the fruit to be effected earlier.  
  Abseission was accompanied by ripening (maturing) of the fruit, as seen by the maturity index results.  
  The maturity index, based on fruit pressure tests, is expressed as a decrease in apple firmness or softening NAA naphthalene acetic acid It will be seen that the use of 2 chloroethylphosphonic acid stimulates both loosening and maturing of the fruit. The addition of NAA reversed the abscission promoting effect without interfering with the ripening process.  
  EXAMPLE 1 1 This evaluation also shows freeze damage resistance.  
  Apple seedlings (Malus domcstica) variety Red Delieious, two weeks old were sprayed with an aqueous solution of 2-chloroethyl-phosphonic acid. Eighteen days later the plants were pre-eoolcd at +2C for one hour and then kept at 6C for 2 hours and thirty minutes. The frozen plants were then cultured and the following data recorded.  
 Treatment 7: Plants surviving freeze Control 0 200 ppm [0O It is apparent from the results o f the foregoing evaluations that the phosphonic derivatives of this invention are capable of imparting a wide variety of plant growth regulating responses.  
 - 20 thylphosphonic acid afterharvest. The results are recorded below.  
 Treatment Tree spray Fruit dip Rate lbs Fruit firmness Yellow color lbs Fruit firmness Yellow color Control 7.2 50 6.9  
 EXAMPLE 12 This evaluation demonstrates the use of a compound of the invention as a growth regulator for accelerating fruit maturity and improving fruit color.  
  Apple (Malus sp.) variety Rome trees were sprayed just prior to normal harvest with aqueous solutions of Z-chloroethylphosphonic acid. Apples were also dipped in aqueous solutions of 2-chloroethylphosphonic acid after harvest. The results are recorded below.  
  As fruit matures to eatable quality the flesh softens. The reduction of fruit firmness on both pre and post harvest treated fruit demonstrates accelerated maturity. Further, use of a compound of the invention will remove green color from the fruit thereby increasing deisrable yellow color expression when treated on the tree of after picking. Often genetically yellow apples remain quite green and fail to obtain full yellow color under various growing conditions. Pre or post harvest treatments will be of economic value for increasing the Treatment Tree spray Fruit dip Rate lbs Fruit firmness red color lbs Fruit firmness red color Control 16.9 80 16.6 80 500 ppm 15.2 95 14.7 94 1000 ppm 14.3 92 13.9 96  
 expression of yellow color for marketing yellow apple varieties.  
 EXAMPLE 14 This evaluation demonstrates the use of a compound of the invention as a growth regulator for control of fruit set.  
 at full bloom and at several intervals after full bloom (see table for state of development at different application times) with aqueous solutions of 2-chloroethylphosphonic acid. The results are recorded below.  
 Treatment Date State of Fruit Increase rate ppm applied development set return bloom 0 May 1 Delayed dormant 36.2 0 200 May 1 Delayed dormant 4.6 20 2000 May 1 Delayed dormant 0 0 May 17 Pink 31.4 0 200 May 17 Pink 10.1 15 2000 May 17 Pink 0 0 May 23 Full bloom 28.3 0 1000 May 23 Full bloom 2.9 55 0 June 2 FB 10 days 28.0 0 50 June 2 FB 10 days 29.2 0 250 June 2 FB 10 days 10.6 20 300 June 2 FB 10 days 5.8 0 July 6 FB 44 days 31.7 0 July 6 FB 44 days 29.8 5 250 July 6 FB 44 days 33.6 5 1000 July 6 FB 44 days 1.6 10  
  Mature trees with 4 replication branches on separate trees per treatment. Fruit per 100 blossom cluster as determined August 1. FB Full bloom Apple (Malus sp.) variety Golden Delicious trees were sprayed prior to harvest with aqueous solutions of 2-chloroethylphosphonic acid. Apples of the same variety were also dipped in aqueous solutions of 2-chloroe- Reducing fruit set during the current year is a common grower practice known as thinning..&#34; Excellent thinning or reduction of fruit set was obtained following treatment with a compound of the invention Apple (Malus sp.) trees were sprayed prior to bloom,  
 when applied from the delayed dormant stage through 44 days after full-bloom. Compounds of the invention are also useful for increasing return bloom and fruit set the following year.  
 EXAMPLE 15 This evaluation demonstrates the use of a compound of the invention to induce freeze resistance.  
  Apricot (Prunus sp.) trees were sprayed with aqueous solutions of 2-chloroethylphosphonic acid. The results are recorded below.  
 Treatment 71 Fruit buds killed with l lF Control 94 200 22 300 32 500 1] Freeze resistance of fruit buds and flowers will insure economic crop production on trees treated with a compound of this invention whereas untreated trees in this trial subjected to 11F will not have sufficient live fruit buds to produce an economic crop for the grower.  
 EXAMPLE 16 Treatment &#34;A increase in shoots /r flower and fruit rate (spears) ahscission Control 0 500 ppm 75 1500 ppm 100 4500 ppm 52 100 9000 ppm 27 Hill Asparagus normally produces shoots or spears from rhizomes which must be harvested daily during the production period. With a compound of the invention, treatment of fall ferns (adult plant form). first emerging spring spears, or soil treatment of rhizomes would be of economic value for increasing yield by stimulating uniform spear emergence for a single harvest or reducing the number of daily harvests. Further, the ability of the asparagus plant to produce shoots may be increased by causing flower and fruit abscission on the female plant with a compound of the invention.  
  Elimination of summer fruit from the female plant removes the burden of maturing fruit enabling the plant to accumulate food reserves in the rhizomes for increased shoot production the following spring.  
 EXAMPLE 17 This evaluation demonstrates the use of a compound of the invention as a fruit ripening agent.  
  Avacado (Persea sp.) trees were sprayed with aqueous solutions of 2-chloroethylphosphonic acid just prior to normal harvest. Unripe fruits were also removed from the tree and dipped in aqueous solutions of 2-chloroethylphosphonic acid for one minute. The results are recorded below.  
 Treatment Control 0 3 250 20 27 500 73 82 Treatment with a compound of the invention accelerated fruit ripening of avacadoes when applied as a preharvest spray or as a postharvest solution dip.  
 EXAMPLE 18 In another branching evaluation an aqueous solution of 2-chloroethylphosphonic acid was sprayed to run-off on azalea plants.  
  Two months later the plants were inspected and the following noted.  
 Treatment rate Observation Bud formation was stimulated and there were many lateral shoots Very many lateral shoots close to plant top 30 l kg/ ha 2 lag/ha Evaluations preformed using lower rates gave good flower induction.  
 EXAMPLE l8-A This evaluation shows use of a compound of the invention to ripen bananas by stimulating metabolic processes associated with ripening.  
  Cut banana stalks bearing fruit were artificially ripened by being dipped in aqueous solutions of 2-chloroethylphosphonic acid at concentrations ranging from 100 to 4,500 ppm. This effect, which presumably results from the destruction of chlorophyll and stimulation of carotenoid development, is of economic importance as unripe fruit are imported into European and Scandinavian countries and then artificially ripened before distribution.  
 EXAMPLE 19 This evaluation demonstrates the use of a compound of the invention to increase stem formation (tillering) and reduce overall stem height. Summer barley (variety Impala) was sprayed with aqueous solutions of 2-chloroethylphosphonic acid, with or without urea, at the l 2 leaf stage and the plants inspected some 10 weeks later. The following results were obtained, from which it will be seen&#39;that the compound of this invention either alone or with the urea decreased the total plant height (thus decreasing any tendency towards lodging) while increasing the average number of stems per plant (thus increasing potential crop yield).  
  This evaluation demonstrates the use of a compound of this invention to increase crop yield. It shows that compounds of the invention can increase the fruit number and the weight of the aerial parts of Phaseolus vulgaris (varieties snapbean and kidney bean) when applied in aqueous solution at the first trifoliate stage at the rate of l.l2 kg/ha.  
 tions of Z-chloroethylphosphonic acid. Eleven days later the plants were pre-cooled at +2C for one hour and then kept at V2C for 2 hours and twenty minutes. The frozen plants were then cultured in a greenhouse and the following data was recorded.  
 Treatment &#34;/1 Plants surviving freeze Control (0) 0 200 ppm l00 no damage 2000 ppm 100 no damage EXAMPLE 23 French beans variety Dwarf bean the Prince&#34; were treated with aqueous solutions of 2-chloroethylphosphonic acid at the rates indicated at the 1 /2 2 true leaf flower bud stage. The following increases in total yield were noted.  
 Compound of the Plant variety Results (60 days after treatment) invention Pods/plant Plant Weight (grams) pyrocatechol cyclic ester of Snapbean 2-chloroethylphosphonic acid Control 6 29 treated 70 2chloroethyl- Kidney bean phosphonic acid Control 83 treated 134 lnthis evaluation the treated plants were also shorter, with heavier stems, and had appreciably more lateral shoots than the controls. The effects are desirable, in that they reduce lodging and give greater crop bearing vegetation respectively.  
 EXAMPLE 21 This evaluation also demonstrates the use of a compound of the invention to increase crop yield.  
  French beans, variety Dwarf bean (The Prince), were treated with aqueous solutions of 2-chloroethylphosphonic acid at a rate of 0.5 kg/ha at the l /2 2 true-leaf stage. The crop was harvested twice and, as the following results show, an increase in yield per plant over that of the control plants was noted at the second harvest.  
 Treatment Total yield per plant (gms) Control 4l 0.25 46 0.50 48 EXAMPLE 24 This evaluation demonstrates the use of a compound of the invention as a growth regulator for inducing fruit abscission as an aid to harvest of mature fruit.  
  Black currants (Ribes sp.) shrubs were sprayed prior to harvest with aqueous solutions of 2-chloroethylphosphonic acid. The results are recorded below.  
  Treatment 7! Fruit abscission Treatment Average yield per plant (gms) rate ppm following a hand shake at 2nd harvest Control 3 Control (0) 6 500 89 Z-ehloroethyl- 27 2000 9| phosphonic acid 5000 91 EXAMPLE 22 This evaluation demonstrates the use of a compound of the invention to impart freeze damage resistance.  
 Seedling beans (Phaseolus vulgaris); variety Blue Lake, 2 k weeks old, were sprayed with aqueous solu- Treatments loosened currants on the shrub and as a result of weakening the link between the stem and the fruit, black currant fruit was easily removed following a hand shake of the plant. Treatment rates of 2,000 and 5,000 ppm also induced leaf defoliation.  
  Further, fruit samples collected from treated bushes contained no green berries indicating uniform stimulation of ripening had occurred when treated with a compound of the invention. i A  
  Stimulating fruit abscission with a compound of the invention will be of economic value for crop harvest by reducing the labor and time required to pick the fruit.  
 EXAMPLE 25 Treatment 7! Fruit abscission xi ripe l&#39;ruit rate ppm following a hand shake Control 20 55 500 86 78 2000 95 85 5000 97 85 Treatments loosened blueberries on the bush and as a result of weakening the link between the stem and the fruit. blueberry fruit was easily removed following a hand shake of the plant. Treatment rates of 2,000 and 5,000 ppm also induced slight leaf defoliation.  
  Further, fruit samples collected from treated bushes contained no green berries indicating uniform stimulation of ripening had occurred when treated with a compound of the invention.  
  Stimulating fruit abscission with a compound of the invention will be of economic value for crop harvest as a result of increased crop recovery and ease of fruit removal.  
 EXAMPLE 26 This evaluation demonstrates the use of a compound of the invention to increase yields and reduce plant height. I  
  Soybean (Glycine max) plants were sprayed at the 9-l2 trifoliolate leaf stage with aqueous solutions of Z-chloroethylphosphonic acid. The results were recorded below.  
 Treatment 71 Height Rate lh/A &#34;/1 Yield inhibition Control 100 I52 23 l.() l l9 l4 EXAMPLE 27 ml portions of 2-chloroethylphosphonic acid in aqueous solution were applied at rates of up to 10,000 ppm to ornamental plants of the Bromiliadaceae family. and increases in flower induction were observed.  
 EXAMPLE 28 This evaluation demonstrates the use of a compound of the invention to induce freeze resistance.  
  Cherry (lrlmus sp.) trees were sprayed with aqueous solutions of Z-chloroethylphosphonic acid. The results are recorded below.  
  Fruit buds killed with l 1 F freeze four Treatment months after treatment on variety rate ppm BING CHlNOOK RAINIER AVERAGE Control 3 l 14 3| 500 6 3 Ill 6 1.000 s 2 5 2.000 0 4 3 Protection of fruit buds and subsequent flowers from freeze damage is economically valuable to the grower to insure annual crop production.  
 EXAMPLE 29 Treatment Avev number of Rate lb/A &#39;71 Yield kernels per car &#34;/1 Lodging Control l00 579 27 These results show that an increase in yield was obtained with fewer kernels per car indicating an increase in kernel size following treatment with a compound of this invention. Treatment also reduced lodging and increased the number of above-ground brace roots.  
 EXAMPLE This evaluation demonstrates the use of a compound of the invention to control growth.  
  Corn (Zea sp.) plants were sprayed at the eight-leaf stage with aqueous solutions of Z-chIoroethylphosphonic acid. The results were recorded below.  
 Treatment 3 Months after application Increase in number of brace rate lb/A height reduction roots reaching soil surface Control 0 O.25 13 O 0.50 14 l 1.0 17 3 2.0 23 3 4.0 39 4 The term height inhibition is a measure of reduction in stem height. The shorter plant showed less lodging.  
  Distance of ear from the soil surface to the ear tip was reduced with all treatments. Organ primordia (tissue in. the stem which develops into roots, leaves or fruit) was stimulated as evidenced by increased numbers of brace roots from the stem reaching the soil surface.  
 EXAMPLE 3] This increased yield of cotton is apparent. The reduction in plant height is useful, being indicative of a general reduction of non-useful vegetation.  
 EXAMPLE 33 This evaluation demonstrates use to give increased branching.  
  Ornamental shrubs were sprayed to run off with aqueous solutions of 2-chloroethylphosphonic acid and the plants were inspected 3 months later and the following noted:  
 Preharvest spray Preharvest and Postharvest increase in Treatment 7r increase in abscission rate flowers fruit leaves ripe berries Control 0 O 0 0 400 ppm 35 0 20 600 ppm 60 60 5 35 800 ppm 75 75 I0 50 1200 m 97 90 70 4000 m 100 I00 85 90 25 Both pre and post harvest treatments with a com- Shrub Treatment Branch Height pound of this invention were effective for increased rip- (cm) ni 5 e ng and reducing the number f immature green bcr Chrwnmhcmum Comm (0) m0 rles. Timely applications ot the compounds of this m- (variety vention to flowers. fruit and leaves on the tree will inw Gipsy) 100 m 2 7...- duce abscission. 500 ppm 3 v 1000 ppm 20 38 In many parts of the world coffee has a distinct num- Cunminn 0mm (0) 4 bcr of flowerings spread over a number of weeks. The (Pink) flowering is often closely related to periods of moisture. 2g; 5: Since different flowering s ripen at different times, a Fuchsia Comm (0) 21 21 number of selected fruit pickings are required. Further, 100 ppm 33 23 1000 ppm 31 26 fruit set from premature flowering is often lost to drought which lowers plant vigor as a result of supporting fruit which abort before maturity. By use of a growth regulator of this invention it will be possible to remove unwanted flowers thereby controlling harvest period and reducing the number of pickings required to harvest the crop. In addition application of a chemical of this invention will induce fruit abscission or decrease the&#39; pull-force required to remove the coffee from the tree. This effect should be of economic value to the development of mechanical harvesting techniques. Further, treatment of the fruit both pre and postharvest will accelerate maturity as evidenced by the increased number of red berries.  
 EXAMPLE 32 Treatment Rate kg/Ha Bolls/Plant Change in plant height Control (0) 19.1  
  It will be seen that in general the treated plants were more highly branched than the control plants, thus giving more potential flower sites. It will also be seen that the chrysanthemum plants heights were reduced.  
 EXAMPLE 34 Treatment &#34;/1 Defoliation 10 days rate ppm after treatment Abscission (means falling-of or being freed from the plant) is of economic benefit in cotton for machine harvesting efficiency. Leaf removal reduces green stain of cotton lint, permits earlier harvest, reduces boll rot, removes leaf insect problems and reduces lodging.  
 EXAMPLE 35 Treatment Fruit removal Soluble increase rate force in grams solids 71 red color Control 350 l3.6 250 ppm 250 15.5 20 500 ppm 2l0 l5.6 2l 1000 ppm I55 I69 30 2000 ppm 80 l6.4 37  
  Use of a compound of the invention will lower the pull-force of the fruit making it easier to pick. The link between the fruit and the stem is weakened and upon picking the fruit is separated from the stem. Separation of fruit from the stem is economically valuable since it reduces sorting and stem removal during processing. It is understood, however. that this effect would not be desirable for cherries which are processed with the stems attached. Treatment with 1,000 and 2.000 ppm caused sap flow, gum, to extrude from lenticils of treated twigs; leaf abscission was also recorded.  
  Acceleration of harvest maturity is apparent by the increase in red color expression and the increase in soluble solids. A spaced acceleration of fruit maturity, time-controlled by a compound of the invention will also be of economic value for extending the normal harvest period.  
 EXAMPLE 36 Treatment Fruit removal Ave time to &#34;/r Removed rate ppm force in grams harvest (seconds) without stems Control 352 28.7 50 250 273 l 1.5 90 500 237 l0.5 95  
  The reduction in fruit removal force following use of a compound of the invention is reflected in easier harvest. The harvest time was reduced 60 percent on treated trees.  
  Further, the reduction in shaking time required for harvesting a tree or a reduction in machine shaking force that is required to remove the fruit will lower the danger of tree injury and reduce fruit bruising. Reducing fruit removal force will increase the percentage of total crop removed.  
  The link between the fruit and the stem is weakened and when machine harvested or hand picked a high percentage of fruits on treated trees are removed without stems. Use of a compound of the invention results in a smoother separation of the fruit from the stem with a reduction in the proportion of fruits with torn flesh at the point of separation. This smooth separation of stem and fruit without tearing the skin is of importance in quality maintenance through postharvest handling operations of both sweet and tart cherries.  
 The trend is toward increased use of machines to mechanically harvest fruit. This fruit is often difficult to remove. however, use of a compound of the invention to hasten or promote the abscission process is of economic value to aid and improve harvest efficiency.  
 EXAMPLE 37 Cucumber plants were sprayed with an aqueous solution of 2-chloroethylphosphonic acid at the 1-3 true leaf stage. They were then inspected at the l3-true leaf stage. and the following noted.  
 Rate (ppm) No. female flowers The increase in flowers is to be noted at the low rates of treatment.  
 EXAMPLE 38 Treatment &#34;/1 Growth inhibition 7: lncrease red color rate ppm Spring treatment Preharvest Postharvest Control 0 0 0 500 I0 30 35 5.000 30 50 48 10,000 50 65 68 Vegetative shoots which develop after spring treatment with a compound of the invention had shorter internodes and were shorter in length when compared to untreated plants. Terminal runner growth was inhibited ten to fifty percent. This inhibition is of economic value for slowing down the normal excessive vegetation often produced in bog production. When excessive vegetative growth occurs, fruit set and yield are generally reduced the following year.  
  Treatment of cranberries prior to harvest or after picking with a compound of the invention increased the percent and uniformity of red color expressed by the fruit. Induction of fruit abscission was also recorded with a preharvest treatment of 10,000 ppm.  
  Color&#39;enhancement in fruit is an economic factor in fruit quality determinations.  
 EXAMPLE 38-A value for increasing fruit yields through early fruit set by female flowers.  
 EXAMPLE 39 This evaluation demonstrates the use of a compound of the invention for inducing disease resistance.  
  Mildew-susceptible cucumber (Cucurbits sp.) plants were sprayed with aqueous solutions of 2-chloroethylphosphonic acid. The results are recorded below.  
 Node of first Cultivar and normal Treatment Node of lst floral bud nonaborted flower Sex expression rate ppm Male Female or perfect Male Female or perfect Wisconsin SMR l8 1.0 4.0 3.5 4.0 (monoecious) 250 19.5 I0 I95 4.5 500 1.0 5.0 MSU 713- 0 1.0 2.0 (gynoecious) 250 l.0 4.5 500 1.0 5.0 Lemon 0 1.0 l3.5 1.0 13.5 (andromonoecious) 250 I50 1.0 15.0 4.0 500 1.0 4.5  
 &#34;No male flowers produced at the first nodes Most cucumber cultlvars and monoeclous WhlCh 1s a term meaning that one or more male flowers develop Treatment plants leaf area on the first few nodes followed by an occasional female flower developing at later nodes. The monoecious eul- Comm] 100 m0 tivar treated with 2-ehloroethylphosphomc acid pro- 2? pp duced several female but no male flowers at each of the 2; gy 7, 0  
 first eighteen nodes on the main stem, while untreated plants had several male flowers at each of these nodes.  
  Gynoecious cucumbers which normally produce female flowers except under environmental stress were not modified by chemical treatment since control as well as treated plants produced only female flowers.  
  The andromonoecious cultivar which normally develops many nodes with only male flowers on the main stem before producing single perfect flowers as well as several male flowers on some of the later nodes responded to chemical treatment of 2-chloroethylphosphonic acid by producing several perfect or female EXAMPLE 39-A This evaluation demonstrates the use of a compound flowers but no male flowers at each of the first fourteen of the invention for regulation of sex expression in nodes on the main stem. monocclous P Cucumber (Cucumis sp.) plants of the monoecious The flower buds at the first three nodes of treated variety Wis nsin MR 18 were sprayed with aqueous plants of each cultivar aborted before fertilization, Solution of 2-ehloroethylphosphonic acid at different however, flowers at subsequent nodes were normal d stages of development of vegetative growth. Seed treatdid not abort after fertilization. ments were also made by immersing seeds in 2-chloroethylphosphonic acid for two hours before planting. The Early induction of female flowers is of economic results are recorded below.  
  Node of Node of first Stage Treatment first floral bud nonaborated flower treated ppm male female male female Control 0 &#39;l .0 0.0 5.6 0.4 1.8 0.2 5.6 0.4 Seed 500 L0 0.0 6.0 0.3 1.6 0.2 6.0 0.3 1.000 1.0 10.0 7.3 :02 1.7 :0.2 7.3 10.3 2.000 1.0 0.0 6.8 0.3 L8 0.2 6.8 0.3 Cotyledon 3.0 0.4 L0 0.0 3.0 0.4 2.0 0.4 250 5.2 $0.7 l.0$0.0 5.2 $0.7 l.7 $0.3 500 9.0 $0.3 [.0 $0.0 9.0 $0.3 2.6 $0.4 lst leaf 125 10.0 0.4 1.0 0.0 10.0 0.4 1.6 0.2 250 1.0 0.0 3.0 1 0.4 500 [.0 0.0 ll.0 0.5 3rd leaf I25 l.0 0.0 3.0 0.5 2.5 0.4 6.5 0.4 250 l.0 0.0 6.5 0.7 500 1.0 0.0  
 No male floral huds produced at the first 10 nodes. All female flowers at the first l0 nodes aborted before anthesis.  
  Immersion of seeds in 2-chloroethylphosphonic acid for two hours before planting had no effect on sex expression. however, foliage applications in the cotyledon stage or later resulted in shortened internodes and earlier development of female floral buds. Application of 2-chloroethylphosphonic acid in the tree-leaf stage modified sex expression at the cotyledonary node even though floral initiation and differentiation at this node should have been completed at the time of treatment indicating that the chemical inhibited development of the stamen and stimulated pistil development.  
  Female flower induction with a compound of the invention was not limited to those flowers differentiated at the time of treatment. A single application had very persistent effects and influenced sex expression offlowers that were not yet initiated at the time of treatment.  
  The regulation of sex expression and growth habit of cucumber plants has important potential applications. Fruit set early will increase yield potential. Use of a compound of the invention has value for hybrid seed production which can be accomplished by treating the monoecious maternal parent to inhibit its formation of male flowers thereby eliminating or reducing normal hand removal of male flowers.  
  Further. the problem of fruit setting too close to the base of the plant to permit multiple mechanical harvests can be overcome by the aborting ofthe first flowers by treatment with a compound of the invention.  
 EXAMPLE 40 This evaluation demonstrates the use of a compound. of the invention for regulation of sex expression and control of vegetative growth.  
  Cucumber (Cucumis sp.) varieties Wisconsin SMR l8 (monoecious) and variety Lemon (andromonecious) were sprayed with aqueous solutions of 2-chloroethylphosphonic acid and gibberellic acid at the first to third true leaf stage of vegetative development. The results are recorded below.  
  2-chloroethylphosphonic acid on sex expression and growth could be explained on the basis of this antigibberellin activity. Gibberellic acid antagonizes the response of cucumbers with respect to female flower induction caused by 2-chloroethyl hosphonic acid. Further. the effects of Z-ehlorophosphonic acid on vegetative growth inhibition were also antagonized by gibberellic acid. Gibberellic acid is known to stimulate male sex expression and stimulate vegetative growth.  
  The use of 2-chloroethylphosphonic acid to increase the number of female flowers produced early in the vegetative growth period can be utilized to increase the amount of fruit ripe at the same time, thereby improving adaption to mechanical harvest. Vegetative growth l5 inhibition as evidenced by shortening of the intcrnodes will allow closer spacing and higher populations and consequently higher yields per acre.  
 EXAMPLE 4] This evaluation demonstrates the use of a compound of the invention for regulation of sex expression.  
  Cucumber (Cucumis angilic&#39;us) plants were treated with aqueous solutions of 2-chloroethylphosphonic acid at various growth stages. The results are recorded below.  
 Treatment &#39;71 Male flowers produced in 25 nodes rate 13 leaf 3-5 leaf 5-8 leaf 1-3 3-5 +5-8 leaf Control 85 r 85 85 I, 85.  
  25 30 32 36 30- 50 l0 l4 l6 8 I25 0 4 6 .0 250 0 2 4 g 0 500 0 0 2 O Certain varieties of cucumbers set fruit without fertilization (parthenocarpic development). The English forcing cucumber used in this trial is an example of 4 such a cucumber which produces very few seeds. how- Node of first Number of flowers flower on first 10 nodes Rate Length of first Female or Male Female 0r Male Treatment ppm internode (cm) perfect perfect WISCONSIN SMR 18 Control 0 7.7 t 0.6 8 0 i 0 5 2.0 i 0.0 2.0 t 0.0 33.4 i 1.8 Gibberellic 2000 16.0 i 0.7 1.3 i 0.3 0.0 33.0 i 4.3 acid 2-chl0r0ethyl- 250 3.7 i 0.2 2.0 i 0 O l4.3 0.5 14 0 L7 0.0 phosphonic acid Gibberellic 2000 10.9 i 0.6 3.0 i 0.5 7.0 t 0.5 4.0 i 0.5 8.3 i 2.0 acid 2- 250 chloroethylphosphonic acid LEMON Control 0 4.6 1- 0.5 3.0 i 0.0 0.0 26.6 i 0.5 Gibberellic 2000 8.3 i 0.3 5.7 i 0.7 0.0 18.0 1 1.6 acid 2-chl0ro- 250 3 0 i 0.2 8.0 i 0.5 l 1.7 1 L9 4.0 t 0.8 2.3 I 4.1 ethylphosphonic acid Number of plants for internode length measurements 12 days after treatment.  
  Application of 2-chloroethylphosphonic acid increased the number of female flowers produced and induced expressionof female flowers earlier than on untreated plants. Use of a compound of the invention has anti-gibberellin activity. For example. the influence of ever. when pollen from male flowers is transferred to ,5 female flowers by natural or artificial means fertilization and seed set results. When these normally parthenocarpic cucumbers set seed as a result of pollination, the fruit is misshappen and the general taste quality is reduced usually as a result of a bitter flavor.  
  Use of the compound of the invention to reduce .or eliminate male flower production will remove the pollen source thereby insuring that the fruit set will be parthenocarpic and unfertilized.  
 EXAMPLE 42 This evaluation demonstrates the use of a compound of the invention for regulation of sex expression.  
  Gynoecious cucumber (Cucumis sp.) of the variety Piccadilly were treated with aqueous spray solutions of 2-chloroethylphosphonic at the first to third true leaf stage of vegetative growth. The results are recorded below.  
 Treatment rate ppm 71 Female flowers in first l5 nodes Control (13 )3 50 I00 I25 100 250 100 500 100 EXAMPLE 43 This evaluation demonstrates the use of a compound of the invention for accelerating fruit maturity and increasing fruit size of fruit characterized by a doublesigmold growth development pattern.  
  Fig (Ficus carnica) trees and fruit were sprayed with aqueous solutions of 2-chloroethylphosphonic acid during the second half of growth period II. The results are recorded below.  
 Treatment Days until Fresh weight Total soluble rate ppm ripening grams solids A Control 28 28.7 7.0  
  250 7 84.0 l7.4 I000 7 90.0 l7.0 4000 Abscissed before ripening Treatment with a compound of the invention during the second period of Stage II initiated the growth Period Ill characterized by rapid fruit enlargement of the pericarp and accelerated harvest maturity. A treatment of 4,000 ppm abscised the fruit before ripening. Treated fruits developed excellent flavor as evidenced by the increase in total soluble solids.  
  Use ofa compound of the invention offers a promising means of accelerating fig maturation and control of harvest maturity offruit.  
 EXAMPLE 44 This evaluation demonstrates the use of a compound of the invention as a fruit ripening agent.  
  Fig (Ficus c&#39;aricalfruit were sprayed and dipped in aqueous solutions of 2-chloroethylphosphonic acid after harvest from the tree. The results are recorded below.  
 Treatment rate ppm &#39;7! Ripe fruit 7 days after treatment Control 6 250 40 Certain fruit such as figs, bananas, pears, peaches, and tomatoes must be picked in the immature&#34; stage before they are fully ripened in order to reduce bruising which would occur during shipment to market if the fruit were soft and ripe. Use of a compound of the invention as a ripening agent to treat immature&#34; fruit just prior to shipment to market or treatment after arrival at market is of economic value for inducing edible maturity without loss of quality during shipment.  
 EXAMPLE 4 5 i This evaluation demonstrates the use of a compound of the invention for accelerating fruit maturity,  
  Fig (Ficus carn&#39;i ca) fruit were sprayed or &#39;in aqueous solutions of 2-chloroet hylphospho nic acid after picking. The resultsare recorded below.  
 Treatment rate ppm /r- Ripe fruit 7 days after treatment Control l0 S00 2000 l 00 5000 Control of edible fruit maturity is of economic value. Often fruits must be harvested before they are ripe in order to avoid bruising and subsequentloss of fruit quality during shipment to market. However, for&#39;maxi: mum consumer appeal fruit must be ripe when it arrives at the market or shortly thereafter, consequently, use of a compound of the invention to accelerate edible market quality of fruit is of economic importance.  
 EXAMPLE 46 This evaluation demonstrates the use of a compound of the invention for increasing fruit sizeof citrus.  
  Grapefruit (Citrus paradisi) treesspi ayed with aqueous solutions of 2-chloroethyl phosph&#39;onic acid when immature fruit were A to 1 meats results are recorded below. i v  
 Treatment rate ppm &#34;/1 Increase in fruit size at harvest Control 25 50 I00 21 Use of a compound of the invention as a sizing spray is of economic value for increasing the yield of citrus.  
 EXAMPLE 47 This evaluation demonstrates the use of a compound of the invention as a growth regulator for inducing abscission of nuts.  
 Treatment &#39;71 nut abscission &#39;7! increase in shuckrate following a tree shake split. postharvest Control 23 250 ppm 55 47 500 ppm 89 85 l000 ppm 94 96 2000 ppm 97 96 Treatments loosened nuts on the tree and induced shack-split. Shuck-split is a term used to designate abscission 0f the hull (exocarp) and opening or a loosening of the nut from the outer hull. Leaf abscission was recorded with a preharvest treatment of 2,000 ppm. Treated trees could be harvested 1 to 3 weeks earlier. This is of economic value since untreated nuts are often difficult to remove from the tree at optimum quality and when nuts remain on the trees for extended periods before they can be removed easily, quality of the nut isgenerally reduced. Postharvest dip treatments also induced abscission in the form of shuck-split enabling the nut to be removed easily from the hull.  
  Use of a compound of the invention as a growth regulator for inducing abscission of nuts is of economic value to harvest techniques, such as mechanical tree shaking, in order to remove the nuts at optimum harvest quality.  
  EXAMPLE 48 This evaluation demonstrates the use-of a compound of the invention as a growth regulator increasing fruit size.  
  Grape (Vitis sp.) vines were sprayed three to four weeks before flowering commenced with aqueous solutions of 2-chloroethylphosphonic acid. Similar treatments were also applied at flowering time using aqueous solutions of 2-chloroethylphosphonic acid. The results are recorded below.  
 Weight of berries in grams at harvest Use of a compound of the invention preflowering when the clusters of rudimentary flowers appear with the leaves in early spring will reduce the number of flowers developing resulting in improved nutrition for those remaining. As a result you increase or obtain a better set of berry fruit and increase berry size and cluster weight at harvest. Application at the flowering to shatter stage reduces the crop load so that the remaining fruit will develop and mature properly. Proper cluster thinning of fruit will insure or favor the nutrition of retained clusters and berries. thereby improving berry size, coloring and maturity. Berry thinning improves quality since an over-abundance of berries makes the clusters too compact and interferes with proper coloring and delayed maturity.  
  Use of a compound of the invention is of economic value for increasing berry size and fruit quality.  
 EXAMPLE 4) This evaluation demonstrates the use of a compound of the invention for controlling vegetative growth and inducing leaf senescence.  
  Grape (Vitis sp.) vines were sprayed during vegetative growth periods with aqueous solutions of 2-chloroethylphosphonic acid. The results were recorded below.  
  Inhibiting vegetative growth is of economic value to reduce the amount of vine pruning required and to allow sunlight to penetrate the vines which is important for quality fruit ripening. The September spray was of particular value for accelerating senescence. Senescence is a term used to describe the processing of aging or maturing of plant tissues on an annual basis. The September spray treatments accelerated the plant senesence which was expressed by a yellowing of leaves, leaf abscission, cessation of vegetative growth and a hardening of the stem tissue. Induction of scnescene in of economic value for reducing freeze damage which often occurs when grapes are allowed to continue vegetative growth into the fall or winter season.