METHOD OF PREVENTING PREMATURE FRUIT DROP FROM APPLE TREES

Abstract: A method of preventing fruit drop in apple trees by application of cyclanilide to the tree. A method of improving the quality of apples.

Description: Method of Preventing Premature Fruit Drop from Apple Trees The present invention provides a new method of preventing fruit drop from apples trees and a method of improving apple quality. A known problem in the production of apples is the premature loss of fruit from trees due to maturation of fruit before the fruit can be harvested. Fruit that matures more rapidly than the majority of fruit on a tree has a tendency to drop off the tree, thus lowering the yield of fruit per tree. This problem has substantial adverse implications to apple growers since the growers wish to harvest apples generally one time per growing season. To harvest fruit at multiple intervals to prevent loss of prematurely dropped fruit during the ripening period adds to the cost of production and is undesirable. Thus there exists a need for controlling premature fruit drop in apple trees. An object of the present invention is to provide a method of preventing fruit drop in apple trees. Another object of the present invention is to provide a method of improving the quality of apples on apple trees and/or when harvested. These objects are met in whole or in part by the present invention. The present invention provides a method of preventing premature fruit loss from an apple tree, e.g. a tree in need of prevention of fruit drop, which method comprises applying a composition comprising cyclanilide or an agriculturally acceptable salt thereof to the tree. Cyclanilide is also known as l-(2,4-dichloroanilinocarbonyl)cyclopropane carboxylic acid. It and salts thereof may be prepared by methods described in US Patent 4736056 or other references known to the skilled addressee. In a preferred embodiment, cyclanilide is applied to the tree by spraying a liquid composition on the leaves of the tree and/or on the fruit. The compositions according to the instant invention generally comprise from about 0.5 to about 95% cyclanilide The remainder of the composition up to 100% generally comprises a carrier as well as various additives such as those hereafter indicated. The composition also may comprise a surfactant, preferably a non-ionic surfactant. "carrier", there is meant herein an organic or inorganic material, which can be natural or synthetic, and which is associated with the active ingredient and which facilitates its application to the locus to be treated. This carrier is thus generally inert and should be agriculturally acceptable, especially on the contemplated or treated locus or crop. The carrier can be solid (clay, silicates, silica, resins, wax, fertilizers, etc.) or liquid (water, alcohols, ketones, oil solvents, saturated or unsaturated hydrocarbons, chlorinated hydrocarbons, liquified petroleum gas, etc.). Among the many additives, the compositions of the invention can comprise surfactants as well as other ingredients such as dispersants, stickers, antifoam agents, antifreezing agents, dyestuffs, thickeners, adhesives, protective colloids, penetrating agents, stabilizing agents, sequestering agents, antiflocculating agents, corrosion inhibitors, pigments and polymers. More generally, the compositions of the invention can comprise all kinds of solid or liquid additives which are known in the art. The surfactants can be of the emulsifying or wetting type, ionic or non-ionic. Possible surfactants are salts of polyacrylic or lignosulfonic acids; salts of phenolsulfonic or naphthalenesulfonic acids; polycondensates of ethylene oxide with fatty alcohols or fatty acids or fatty amines or substituted phenols (particularly alkylphenols or arylphenols); ester-salts of sulfosuccinic acids; taurine derivatives, such as alkyl taurates; phosphoric esters; or esters of alcohols or polyoxyethylated phenols. When the spraying vehicle is water, the use of at least one surfactant is generally required because the active ingredient is generally not water-soluble. The method of application of the compositions of the invention is generally the spraying of a mixture which has been previously made, by dilution of more concentrated formulations according to the invention. In another aspect of the present invention, application of the composition to the tree is preferably made after the fruit has set, that is after flowers have been pollinated and fruit has formed on the tree. The application is preferably made when the fruit is from 2 to 6 cm in diameter, preferably from 3 to 5 cm in diameter. According to the present invention, it has been surprisingly found that the amount of fruit drop generally decreases as a function of the amount of cyclanilide applied. In general, cyclanilide is applied at a rate from 5 to 500 g ha, preferably from 10 to 200 g/ha, more preferably from 20 to 100 g/ha, most preferably from 25 to 50 g/ha. The present invention also relates to a method of improving the quality of apples, which method comprises applying a composition comprising cyclanilide to the trees on which the apples grow. It has been surprisingly found that apples treated by the method of the invention have a lower starch content than apples not treated by the method of the invention. Preferably the apples have a starch index of from 4.5 to 5 at harvest. The starch index is indicative of the ability of the fruit to be stored over a long period of time. The lower the number means that there is a lower amount of starch, and thus a better quality fruit. It also has been surprisingly found that apples treated by the method of the invention have a higher content of soluble solids than untreated fruit and than fruit treated by prior art compounds as measured by the BRIX index. Generally the amount of soluble solids is from 12.8 to 13 as measured in a BRIX test. In general a higher soluble solids measurement indicates an increase in the sweetness of the fruit. It also has been surprisingly found that apples treated by the method of the invention generally have a greater firmness than untreated fruit and than fruit treated by prior art compounds. The invention also provides a method of delaying fruit maturity in apples which method comprises applying a composition comprising cyclanilide to the trees on which the fruit grow. However, it has been surprisingly found that apples treated by the method of the invention generally have a better color characteristic than fruit treated by prior art compounds. Thus the method of the invention provides an improvement to the art of storage of fruit. The following Examples provide non-limiting illustrations of the invention. EXAMPLE 1 : An orchard of Mclntosh® Apple trees at a stage where the apples were approximately 4.5 cm in diameter were sprayed with an aqueous suspension comprising cyclanilide and Regulaid®, a non-ionic surfactant (0.25% v/v) at several rates. About two months later, the following observations were made: EXAMPLE 2: The process of Example 1 was repeated using an aqueous suspension comprising cyclanilide and a surfactant using an application rate of cyclanilide of 50g/ha. As a comparison, ReTain® ([S]-trans-2-amino-4-(2-aminoethoxy)-3-butenoic acid) was applied according to commercially acceptable methods on another plot of trees and another plot of trees were left untreated. Just before harvest, the following results were obtained: The overall quality of fruit obtained after treatment with cyclanilide was better than that of the untreated fruit and that obtained from treatment by the prior art compound ReTain®. The color of the fruit obtained after treatment with cyclanilide was better than that of the fruit treated by the prior art compound ReTain®.

Claims: CLAIMS 1. A method of improving the quality of apples which method comprises applying a composition comprising cyclanilide to the trees on which the apples grow. 2. A method of preventing premature fruit loss from an apple tree, which method comprises applying a composition comprising cyclanilide to the tree. 3. A method of delaying fruit maturity in apples which method comprises applying a composition comprising cyclanilide to the trees on which the fruit grow. 4. The method according to one of Claims 1-3 wherein the composition is applied after fruit has set. 5. The method according to any one of the foregoing claims wherein the leaves of the tree are sprayed. 6. The method according to any one of the foregoing claims wherein the fruit is sprayed. 7. The method according to any one of the foregoing claims wherein the tree is sprayed when the fruit is from 2 to 6 cm in diameter, preferably from 3 to 5 cm in diameter. 8. The method according to any one of the foregoing claims wherein the composition is an aqueous composition. 9. The method according to any one of the foregoing claims wherein cyclanilide is applied at a rate from 5 to 500 g/ha, preferably from 10 to 200 g/ha, more preferably from 20 to 100 g/ha, most preferably from 25 to 50 g/ha. 10. The method according to claim 1 wherein the apples have lower starch content at harvest, preferably such that the starch index is from 4.5 to 5 at harvest. 11. The method according to claim 1 wherein the amount of soluble solids is from 12.8 to 13 as measured in a Brix test.

Inventors: BALDWIN CHARLES HARRY JR, SZOEKE TIBOR, BALDWIN, CHARLES, HARRY, JR., SZOEKE, TIBOR
Applicants: BALDWIN CHARLES HARRY JR, RHONE POULENC AGROCHIMIE, SZOEKE TIBOR, BALDWIN, CHARLES, HARRY, JR., RHONE-POULENC AGRO, SZOEKE, TIBOR
Application year: 1999
Main classification: A01N53
IPC codes: A01G7, A01G17, A01N37, A01N53