JP2023174308A - Cedar and japanese cypress pollen spread inhibiting agent and pollen spread inhibiting method - Google Patents

Abstract

To provide a technique that inhibits the spread of pollen with high efficiency based on a new action mechanism.SOLUTION: The inventors discovered that treating pre-bloom male flowers of cedar and Japanese cypress with a compound that suppresses their elongation (blooming) leads to a significant reduction in pollen spread. This finding culminates in the completion of this invention.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cedar and cypress pollen scattering suppressant containing as an active ingredient a compound that inhibits the elongation (flowering) of male cedar and cypress flowers that carry pollen, and a method for suppressing cedar and cypress pollen scattering using the compound. .

Pollen, which is a particulate male reproductive cell formed in the anthers of stamens in angiosperms and in the pollen sacs of male flowers in gymnosperms, is dispersed into the outside world (air and water) or transported by other vectors. , pollination is accomplished by contact with ovules containing female reproductive cells of the same species. When a person inhales pollen scattered in the air and comes into contact with the mucous membranes of the nose or eyes, an allergic reaction to the pollen may occur, and this allergic reaction can cause symptoms such as sneezing, runny nose, stuffy nose, and itchy eyes. The disease that occurs is called hay fever.

Plants that cause hay fever are known to include cedar, cypress, ragweed, pine, grasses, mugwort, etc., but hay fever caused by cedar pollen in early spring is particularly noticeable in Japan. Approximately 80% of hay fever in Japan is cedar hay fever, and cedar hay fever is a national disease that affects 30% of the Japanese population.

BACKGROUND ART Various measures have been attempted to combat hay fever, which significantly impairs the quality of life of many hay fever patients during the pollen season. In order to alleviate the symptoms of hay fever, in addition to treatment for the cause, such as desensitization therapy to strengthen resistance to allergens and improve the constitution, protective measures such as administration of antihistamines and adrenocortical hormones, and use of eye drops and masks are taken. However, the most fundamental countermeasure is to reduce the amount of pollen dispersed into the air.

The Forestry Agency has set out ``three axes'' to control pollen sources in order to suppress the scattering of pollen in cedar forests. In other words, by promoting the first ax, ``cut down and use,'' the second ax, ``replant,'' and the third ax, ``don't allow it to come out,'' we will help ensure the healthy and prosperous lives and economic activities of the people in the spring. We are planning to make improvements.

With regard to the third ax, ``Keep it from coming out,'' efforts have been made to put into practical use technologies that suppress the generation of cedar pollen and prevent it from scattering, such as the development and dissemination of cedar pollen prevention agents. Various technological developments are being carried out in response to this.

For example, pollen formation inhibitors of coniferous trees such as Cedaraceae and Cupressaceae are known that contain maleic acid hydrazide or a salt thereof as an active ingredient (Patent Document 1). This drug is applied to the leaves and stems of coniferous trees during the flower bud formation period, and for Japanese cedar, it is applied during the summer months of June to September.

In Patent Document 2, which reports a pollen scattering prevention agent containing a surfactant emulsion of oleic acid and/or linoleic acid (vegetable oil) as an active ingredient, the production of ethylene, which acts as a plant hormone, is induced in Japanese cedar to which the agent is applied. It is thought that the generated ethylene rapidly promotes the respiration of pollen, or in other words, it quickly exhausts pollen, causing it to age rapidly and die. Regarding the timing of application, it is indicated that the agent should be sprayed on male flowers around October when the pollen has matured. In addition, Patent Documents 3 to 8 disclose various derivatives of oleic acid or linoleic acid as active ingredients of pollen scattering suppressants, and these are also used in the early stages of male Japanese cedar flower formation, from August to November, before pollen grains mature. It is recommended that it be applied over a month.

In Patent Document 9, which suppresses pollen scattering by infecting male flowers with the mycelium of Sydowia japonica and causing them to wither, the mycelium suspension is applied in the fall from October to November. In addition to the above, flower bud formation is performed using polyhydric alcohol esters of fatty acids having 2 to 12 carbon atoms (acetic acid, capric acid, caprylic acid, lauric acid, etc.), acetolactate synthase inhibitors, and gibberellin biosynthesis inhibitors. Techniques for suppressing pollen scattering by inhibiting pollen dispersion have been reported (Patent Documents 10 to 13).

Research and development efforts are underway in various places to try to suppress pollen dispersal by applying drugs that inhibit pollen formation in male Japanese cedar flowers, but so far no drug has been found that is sufficiently effective. This has not yet been achieved. Therefore, the development of a new technology that suppresses pollen dispersal with high efficiency based on a mechanism of action different from that previously known can greatly respond to the social demand for reducing the wide range of health damage caused by hay fever. , high demand is expected.

: Japanese Patent Application Publication No. 03-279305 : Japanese Patent Application Publication No. 05-238902 : Japanese Patent Application Publication No. 07-053307 : Japanese Patent Application Publication No. 2009-191053 : Japanese Patent Application Publication No. 2009-191052 : Japanese Patent Application Publication No. 2009-184991 : Japanese Patent Application Publication No. 2009-184990 : Japanese Patent Application Publication No. 2011-037735 : Japanese Patent Application Publication No. 2011-052039 : Japanese Patent Application Publication No. 2012-092174 : Japanese Patent Application Publication No. 2016-216450 : Japanese Patent Application Publication No. 6-024915 : Japanese Patent Application Publication No. 2004-339188

The present invention relates to a cedar and cypress pollen scattering suppressant containing as an active ingredient a compound that inhibits the elongation (flowering) of male cedar and cypress flowers that carry pollen, and a method for suppressing cedar and cypress pollen scattering using the compound. .

By applying (2-chloroethyl)phosphonic acid (also referred to as ethephon or Esler®) or jasmonic acid to male Japanese cedar flowers in early February just before their elongation (flowering), It has been found that the effect of suppressing pollen scattering can be obtained. The conventional cedar pollen scattering inhibitors exemplified above reduce the amount of pollen produced by exclusively inhibiting the flower bud formation and pollen formation process of male cedar flowers. Among the above-mentioned prior art documents, only 3-oxobutanoic acid ester of Patent Document 13 suppresses pollen scattering by inhibiting the flowering of already formed male flowers, but this is related to the present invention (2- chloroethyl)phosphonic acid and jasmonic acid.

In addition, the inventors have also found that the effect of suppressing pollen scattering can be obtained by similarly applying (2-chloroethyl)phosphonic acid or jasmonic acid to male cypress flowers in early March, just before they bloom. I found out. Both cedar and cypress belong to the Cupressaceae family, but they are distinct tree species that should not be grouped together. It is an advantageous feature of the present invention that the pollen grains also exhibit a similarly good pollen scattering suppressing effect.

The pollen scattering control of the present invention is based on the effect of inhibiting the flowering of male flowers immediately before flowering, as described above, and therefore, from summer to autumn, when the flower bud formation and pollen formation of male Japanese cedar flowers, which are the target of action of the conventional drug, occur. It is also applied late, from winter to early spring just before flowering. Furthermore, since the mechanism of action and timing of application are different from those of conventional inhibitors, when the drug of the present invention is applied in combination with those conventional drugs, the effects do not overlap and exhibit an additive or synergistic scattering suppressing effect. There is a possibility.

Therefore, the present application provides the following inventions.

1. A composition for suppressing the scattering of cedar and cypress pollen, which contains as an active ingredient a compound that inhibits the elongation (flowering) of male flowers that carry pollen, and the compound is (2-chloroethyl)phosphonic acid. , jasmonic acid, and phytophysiologically acceptable salts or esters thereof.
2. The composition according to item 1, which is formulated in a form suitable for being sprayed on the surface of male flowers of cedar and cypress.
3. A method for suppressing the scattering of pollen of Japanese cedar and Japanese cypress, the method comprising the step of applying an effective amount of an agent containing a compound that inhibits the elongation (flowering) of male flowers that carry pollen to the male flowers of Japanese Japanese cedar and Japanese cypress. A method, wherein the compound is selected from the group consisting of (2-chloroethyl)phosphonic acid, jasmonic acid, and phytophysiologically acceptable salts or esters thereof.
4. The method according to item 3, wherein the application of the agent to the male flowers of Japanese cedar and cypress is carried out by spraying the agent onto the surface of the male flowers.
5. The method according to any one of items 3 or 4, wherein the agent is applied to male flowers of cedar and cypress between 8 weeks and 1 week before the time when the male flowers start blooming.
6. The method according to any one of items 3 to 5, wherein the agent is applied to the male flower surface as a 0.5 to 10% by weight aqueous solution of (2-chloroethyl)phosphonic acid.
7. The method according to any one of items 3 to 5, wherein the agent is applied to the male flower surface as a 0.1 to 2% by weight aqueous jasmonic acid solution.

FIG. 1 is a schematic diagram showing the male flower formation process of Japanese cedar and the stages at which the pollen scattering suppressants of the present invention and the prior art act.

FIG. 2 shows the results of the ethephon hydrochloric acid aqueous solution application test (Example 1) on Japanese cedar.

FIG. 3 shows the results of the ethephon hydrochloric acid aqueous solution application test (Example 2) on cypress.

FIG. 4 shows the results of the Esrel (registered trademark) treatment liquid application test (Example 3) on Japanese cedar.

FIG. 5 shows the results of the Esrel (registered trademark) treatment liquid application test (Example 4) on cypress.

FIG. 6 shows the results of the jasmonic acid treatment solution application test (Example 5) on Japanese cedar.

FIG. 7 shows the results of the jasmonic acid treatment solution application test (Example 6) on cypress.

FIG. 8 shows the results of a pollen scattering suppression test (Example 7) by applying Esrel (registered trademark) treatment solution to Japanese cedar at different times in December, January, and February.

The plants to which the pollen scattering suppressant of the present invention is applied are coniferous trees whose pollen causes pollen allergy, preferably cedar or cypress. Both cedar and cypress belong to the Cupressaceae family, but only cedar (Cryptomeria japonica) and cypress (Chamaecyparis obtusa) in the Cupressaceae family cause pollen allergy. Both have been used as lumber, garden trees, and street trees in Japan since ancient times.In particular, in response to the increased demand for lumber during the period of high economic growth after the war, cedar and cypress afforestation was actively carried out, and as demand subsequently decreased, felling became less common. As a result, artificial forests of cedar and cypress now account for nearly 30% of Japan's forest area.

However, please note that cedar and cypress are distinct tree species that should not be lumped together. Therefore, in the prior art exemplified above, those that report only suppression of pollen scattering of cedar and do not mention cypress should be considered to have no pollen suppression effect on cypress. In this regard, it is an advantageous feature of the present invention that the pollen scattering suppressant of the present invention exhibits good pollen scattering suppressing effects in both two distinct tree species, Japanese cedar and Japanese cypress, as described below.

In addition, in cedar and cypress, there is a lag of several months between the time when flower buds form in male flowers and flowering occurs, so the timing of applying the pollen scattering suppressant of the present invention, which should be applied just before flowering, is different when the target is cedar and cypress. It differs between cases. For example, in areas where cedar flowers bloom in March and cypress trees bloom in April, the pollen scattering suppressant of the present invention is considered to be applied around February and March, respectively. Preferably, the pollen scattering suppressant of the present invention is applied 8 weeks before, 7 weeks before, 6 weeks before, 5 weeks before, 4 weeks before, 3 weeks before, or 2 weeks before the time when the target cedar or cypress male flowers start flowering. Applies a week in advance or a week in advance.

The cedar and cypress trees to which the pollen scattering inhibitor of the present invention is applied to suppress pollen scattering may be any cedar and cypress trees that form and release pollen, such as natural or artificial forests, street trees, garden trees, hedges, etc. . Furthermore, as shown in Examples, pollen scattering from cut branches collected from trees can also be suppressed.

The pollen scattering suppressant of the present invention contains as an active ingredient a compound that inhibits the elongation (flowering) of male flowers that carry pollen of Japanese cedar or Japanese cypress. The plant hormones ethylene, jasmonic acid, and methyl jasmonate have growth-inhibiting and aging-promoting effects on plants.

In one embodiment, the pollen scattering suppressant of the present invention contains (2-chloroethyl)phosphonic acid (also referred to as ethephon or Esrel (registered trademark)) as an active ingredient. (2-Chloroethyl)phosphonic acid itself is a known compound (CAS RN16672-87-0), and it is commercially available as a single compound (for example, Tokyo Chemical Industry Product Code: C1456) and commercially available ethephon preparations (for example, Ishihara Co., Ltd.). The pollen scattering suppressant of the present invention can be constituted by using Esrel (registered trademark) 10 (Ishihara Bioscience Co., Ltd.) or Nissan Esrel (registered trademark) 10 (Nissan Chemical Co., Ltd.) as an active ingredient. (2-Chloroethyl)phosphonic acid is a derivative of ethylene that acts as a plant hormone, causing various ethylene-induced physiological responses in target plants sprayed with liquid. Suppression of male flower flowering in the present invention is also considered to be a physiological response to ethylene. The pollen scattering suppressant of the present invention is applied in an amount sufficient for Japanese cedar and Japanese cypress to exhibit such a physiological response to ethylene.

In one embodiment, the pollen scattering suppressant of the present invention contains jasmonic acid as an active ingredient. Jasmonic acid itself is a known compound (CAS 221682-41-3) and is commercially available as a simple compound (for example, Tokyo Chemical Industry Product Code: J0004). Jasmonic acid, like ethylene, is a plant hormone that induces various physiological responses in plants. Like (2-chloroethyl)phosphonic acid, it inhibits male flower flowering in Japanese cedar and cypress, but such inhibition is caused by a different system than ethylene.

The amount of the pollen scattering inhibitor of the present invention to be applied that is sufficient to achieve pollen scattering suppression can be determined by those skilled in the art through routine examination of conditions. As will be described later, since the application of the pollen scattering suppressant of the present invention may cause phytotoxicity to other plants, the amount of the pollen scattering suppressant of the present invention to be applied may be determined in consideration of the effect on the surrounding environment. can be determined.

The pollen scattering suppressant of the present invention can be prepared as a composition in any suitable form, such as an aqueous solution or suspension, an oily solution or suspension, an emulsion, an aerosol, a powder, or a granule. The pollen scattering suppressant of the present invention can be used as a neat solution, or diluted, dissolved, or suspended in a predetermined liquid. How to prepare the pollen scattering suppressant of the present invention is a matter that can be appropriately determined by those skilled in the art, taking into consideration the conditions to be actually applied.

In a preferred embodiment, the pollen scattering inhibitor of the present invention is applied to the surface of male flowers as a 0.5 to 10% by weight aqueous solution of (2-chloroethyl)phosphonic acid. In another preferred embodiment, the pollen scattering inhibitor of the present invention is applied to the surface of male flowers as a 0.1 to 2% by weight aqueous jasmonic acid solution.

The pollen scattering inhibitor of the present invention suppresses the elongation (flowering) of male flowers of Japanese cedar or cypress to which it is applied, thereby suppressing the scattering of pollen from male flowers. Therefore, the application timing of the agent is set just before the male flowers bloom. For example, the agent may be applied 8 weeks, 7 weeks, 6 weeks, 5 weeks, 4 weeks, 3 weeks, 2 weeks, or 1 week before the expected date of pollen dispersal. . Since the pollen scattering period of cypress is later than that of cedar, the application of the agent to cypress in the same area may be later than that of cedar. For example, in a region where it is generally recognized that the pollen scattering season for cedar is March and the pollen scattering season for cypress is April, the agent of the present invention can be applied to cedar in January to February and to cypress in February to March. can be done.

Since the pollen scattering suppressant of the present invention is applied immediately before the male flowers bloom, it is applied later than the pollen scattering suppressant that suppresses flower bud formation and pollen maturation as in the prior art. For example, in Patent Document 4 (Japanese Unexamined Patent Application Publication No. 2009-191053), the application period is ``can be applied over a relatively long period from August when male flowers settle to October to November when pollen grains are produced.'' '', which does not overlap with the usual application period of the present invention from January to March (8 to 1 week before male Japanese cedar flowers start blooming in March).

The pollen scattering inhibitor of the present invention inhibits the scattering of pollen from bloomed male flowers by inhibiting the blooming of male flowers. By applying the inhibitor to the target cedar and cypress trees, the amount of pollen scattered is significantly reduced compared to when it is not applied. For example, the pollen scattering amount of Japanese cedar and cypress trees to which the pollen scattering suppressant of the present invention is applied decreases in a dose-dependent manner, and if an excessive amount is applied, male flowers may wither and pollen scattering may be suppressed by 100%. However, since the active ingredient of the present invention may cause phytotoxicity to various plant species as described below, application conditions may be set in consideration of the desired suppression of pollen scattering and the impact on the surrounding environment.

Example 1: Application of ethephon hydrochloric acid aqueous solution to cedar 10%, 1%, and 0.1% ethephon solutions in which ethephon (manufactured by Tokyo Kasei Kogyo) was dissolved in hydrochloric acid aqueous solution (0.01 mol/l), and as a control, hydrochloric acid aqueous solution ( Cut branches collected on February 9, 2021, about two weeks before the flowering of male Japanese cedar flowers, were soaked in water, and the male flowers were soaked with 0.01 mol/l), and then left at room temperature. Flower foam for fresh flowers (DCM Holdings) was used for the water vase, and the pollen was held so that it would fall from the male flower spike into a 5 ml plastic container. After 18 days, the weight of pollen dispersed on each branch was measured and the number of male flowers was counted to determine the weight of pollen dispersed per male flower.

The amount of pollen scattered in the 1% ethephon treatment was 35.5% of the amount in the control, and an effect of suppressing cedar pollen scattering was obtained (FIG. 2). On the other hand, the effect of suppressing cedar pollen scattering was not obtained with 0.1% ethephon treatment. When treated with 10% ethephon, branches and male flowers withered and did not bloom. Furthermore, when treated with 1% ethephon in the field, there was no change in the appearance of the branches and leaves of cedar, and no chemical damage was observed.

Example 2: Treatment of cypress with ethephon hydrochloric acid aqueous solution 10%, 1%, and 0.1% ethephon solutions in which ethephon (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in a hydrochloric acid aqueous solution (0.01 mol/l), and as a control, a hydrochloric acid aqueous solution ( Cut branches collected on March 4, 2021, about two weeks before the flowering of male cypress flowers, were soaked in water, and the male flowers were soaked with 0.01 mol/l), and left at room temperature. Flower foam for fresh flowers (DCM Holdings) was used for the water vase, and fallen pollen was collected by covering the branches with paraffin paper bags. After 22 days, the weight of pollen scattered on each branch was measured and the number of male flowers was counted to determine the weight of pollen scattered per male flower.

The amount of pollen scattered in the 1% ethephon treatment was 29.5% of the amount in the control, demonstrating the effect of suppressing cypress pollen scattering (Figure 3). On the other hand, the treatment with 0.1% ethephon did not have the effect of suppressing cypress pollen scattering. When treated with 10% ethephon, branches and male flowers withered and did not bloom. Furthermore, when treated with 1% ethephon in the field, there was no change in the appearance of the branches and leaves of cypress, and no chemical damage was observed.

Example 3: Application of Esrel (registered trademark) treatment solution to Japanese cedar A commercially available plant growth regulator, Ishihara Esrel (registered trademark) 10 (manufactured by Ishihara Bioscience Co., Ltd., ethephon concentration 10%) was mixed with deionized water 10 times to 100%. 1%, 0.1%, 0.01%, 0.001% treatment solutions diluted 1-fold, 1000-fold, and 10000-fold, undiluted 10% treatment solution, and deionized water were applied to the flowering area of male Japanese cedar flowers. One month earlier, on January 11, 2018, male cedar flowers planted in the experimental forest of the Forestry and Forestry Research Institute's Kansai Branch were soaked. The treated branches with male flowers were collected on February 27, 2018, and placed in water indoors to bloom and collect pollen. Water was placed in a plastic container filled with water, and a plastic container was used to trap pollen on each branch. The pollen weight was measured and the number of male flowers was counted for each branch, and the weight of scattered pollen per male flower was determined.

The pollen scattering amount in the 1% treatment was 15.2% of the scattering amount in the water treatment, and the effect of suppressing cedar pollen scattering was obtained (Figure 4). On the other hand, 0.1%, 0.01%, and 0.001% treatment solutions did not have the effect of suppressing cedar pollen scattering. Furthermore, no change in appearance was observed in the branches and leaves of cedar with the 1% treatment, 0.1%, 0.01%, and 0.001% treatment solutions. In addition, with the 10% treatment solution, branches and male flowers died and did not bloom.

Example 4: Application of Esrel (registered trademark) treatment solution to cypress Cypress Ishihara Esrel (registered trademark) 10 (manufactured by Ishihara Bioscience Co., Ltd., ethephon concentration 10%), a commercially available plant growth regulator, was diluted 10 times with water to 1%. The treatment solution and water were dipped into male cypress flowers planted in the experimental forest of the Forestry and Forest Products Research Institute Kansai Branch on February 12, 2020, about one month before the male cypress flowers bloomed. The treated branches with male flowers were collected on March 22, 2020, and placed in water to bloom and collect pollen. Flower foam for fresh flowers (DCM Holdings) was used for the water vase, and fallen pollen was collected by covering the branches with paraffin paper bags. The pollen weight was measured and the number of male flowers was counted for each branch, and the weight of scattered pollen per male flower was determined.

The pollen scattering amount in the 1% treatment was 11.2% of the scattering amount in the water treatment, and the effect of suppressing cypress pollen scattering was obtained (Figure 5). In addition, no change in appearance was observed in the branches and leaves of cypress due to the 1% treatment.

Example 5: Application of jasmonic acid treatment solution to cedar 1%, 0.1%, and 0.01% jasmonic acid solutions prepared by dissolving jasmonic acid (manufactured by Tokyo Kasei Kogyo) in a small amount of ethanol and adding water, and a control. Male Japanese cedar flowers outdoors were immersed in water on January 17 and February 7, 2022. On March 2, 2022, just before the male cedar flowers bloomed, 10 branches containing male flowers from each treatment were collected, placed in water, and placed at room temperature. Flower foam for fresh flowers (DCM Holdings) was used for the water vase, and the pollen was held so that it would fall from the male flower spike into a 5 ml plastic container. After 11 days, the weight of pollen dispersed on each branch was measured and the number of male flowers was counted to determine the weight of pollen dispersed per male flower.

The amount of pollen scattered in the 1% jasmonic acid treatment was 19.8% in the January treatment and 9.9% in the February treatment compared to the amount in the control, indicating that a cedar pollen scattering suppressing effect was obtained. In addition, the amount of pollen scattered by the 0.1% jasmonic acid treatment was 45.8% of the amount scattered by the control in the February treatment, indicating a suppressive effect on cedar pollen scattering, but no effect was observed in the January treatment. I couldn't. With 0.01% jasmonic acid treatment, no effect of suppressing cedar pollen scattering was obtained in both January and February treatments (Figure 6).

Example 6: Application of jasmonic acid treatment solution to cypress A 1% jasmonic acid solution prepared by dissolving jasmonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) in a small amount of ethanol and adding water, and water as a control were prepared on February 9, 2022. It was applied to male cypress flowers outdoors using a brush. On March 28, 2022, just before the male cypress flowers bloom, eight branches containing treated male flowers were collected from each treatment, placed in water, and placed at room temperature. Flower foam for fresh flowers (DCM Holdings) was used for the water vase, and the pollen from the male flowers was held in a 5 ml plastic container. After 4 days, the weight of pollen dispersed on each branch was measured and the number of male flowers was counted to determine the weight of pollen dispersed per male flower.

The amount of pollen scattered in the 1% jasmonic acid treatment was 10.7% of the amount in the control, and an effect of suppressing cypress pollen scattering was obtained (FIG. 7).

Example 7: Examination of timing of application of Esrel (registered trademark) treatment solution to cedar. Esrel (registered trademark) (Nissan Esrel 10, ethephon concentration 10%), a commercially available plant growth regulator, was diluted 10 times with deionized water. % Esrel (registered trademark) treatment solution and deionized water on December 28, 2021, about two months before the flowering of male Japanese cedar flowers, on January 17, 2022, about one month before flowering, and on January 17, 2022, about two months before the flowering of male Japanese cedar flowers. A week ago, on February 7, 2022, male cedar flowers planted in the experimental forest of the Forestry and Forestry Research Institute's Kansai Branch were soaked in the water. On March 2, 2022, which was just before flowering, which was later than usual, 10 branches with male flowers were collected from each treatment and placed in water indoors to bloom and collect pollen. Flower foam for fresh flowers (DCM Holdings) was used for the water vase, and the pollen was held so that it would fall from the male flower spike into a 5 ml plastic container. The pollen weight was measured and the number of male flowers was counted for each branch, and the weight of scattered pollen per male flower was determined.

The amount of pollen scattered in the 1% Esrel (registered trademark) treatment was 66.1% in the December treatment, 46.5% in the January treatment, and 13.8% in the February treatment, compared to the amount in the control. The effect of suppressing cedar pollen scattering by less than 50% was obtained by the monthly treatment and the February treatment (Figure 8). Furthermore, there were no changes in the appearance of the branches and leaves of the cedar, and no chemical damage was observed.

Example 8: Phytotoxicity test of (2-chloroethyl)phosphonic acid Since ethylene produced by (2-chloroethyl)phosphonic acid has a wide range of physiological effects on plants in general, in carrying out the pollen scattering control of the present invention, Plant damage may occur to surrounding plants. We investigated the possibility of such drug damage occurring.

A 1% treatment solution (containing 1% ethephon) was prepared by diluting Nissan Esrel (registered trademark) 10 (manufactured by Nissan Chemical Co., Ltd., ethephon concentration 10%) 10 times with deionized water. On January 21, 2021, a 1% treatment solution was sprayed onto 38 types of plants in the experimental forest of the Kansai Branch of the Forestry and Forest Products Research Institute in Kyoto City. Thereafter, visual inspections were conducted on February 8th, March 8th, and April 2nd, and those that had some kind of chemical damage were determined to be poisonous. The results of this test are summarized in the table below.

Of the 38 types of plants investigated, 14 types (37%) were found to have chemical damage. Of the 4 types of evergreen coniferous trees, 25 types of evergreen broad-leaved trees, and 9 types of deciduous broad-leaved trees, 0%, 52%, and 11%, respectively, had some kind of chemical damage such as withered branches or fallen leaves. As a typical example of the observed chemical damage, the most severe branch die-off occurred in the evergreen broad-leaved trees Nandina, Cucumber, and Cinnamon. Defoliation also occurred in osmanthus, black osmanthus, and sasanquat. Among deciduous broad-leaved trees, only Japanese plum was observed to be damaged by chemicals, and its flowers fell off early after the buds had bloomed.

Example 9: Jasmonic acid phytotoxicity test After dissolving jasmonic acid (manufactured by Tokyo Kasei Kogyo) in a small amount of ethanol, water was added to prepare a 1% jasmonic acid solution. On February 9, 2022, a jasmonic acid solution was applied with a brush to 68 types of plants in the experimental forest of the Kansai Branch of the Forestry and Forest Products Research Institute in Kyoto City. Visual inspections were then conducted on February 28th, March 25th, and April 14th, and those that had some kind of drug damage by April 14th were judged to have drug damage. The results of this test are summarized in the table below.

Of the 68 types of plants investigated, seven types (10%) were found to have chemical damage. Of the 9 species of evergreen coniferous trees, 34 species of evergreen broad-leaved trees, and 25 species of deciduous broad-leaved trees, 11%, 15%, and 4%, respectively, had some kind of chemical damage such as withered branches or fallen leaves. Typical examples of plants where chemical damage was observed include the evergreen coniferous tree Konotegashiwa, and the evergreen broad-leaved trees such as Manryo and Blackberry. Among deciduous broad-leaved trees, only Japanese plum was found to have chemical damage, and flowering was slightly delayed.

Therefore, application of the pollen scattering suppressant of the present invention at a dose sufficient to suppress pollen scattering may cause phytotoxicity to other plants, so care must be taken to the surrounding environment when implementing it. could be.

Claims (7)

A composition for suppressing the scattering of cedar and cypress pollen, which contains as an active ingredient a compound that inhibits the elongation (flowering) of male flowers that carry pollen, and the compound is (2-chloroethyl)phosphonic acid. , jasmonic acid, and phytophysiologically acceptable salts or esters thereof. The composition according to claim 1, which is formulated in a form suitable for being sprayed on the surface of male flowers of Japanese cedar and Japanese cypress. A method for suppressing the scattering of pollen of Japanese cedar and Japanese cypress, the method comprising the step of applying an effective amount of an agent containing a compound that inhibits the elongation (flowering) of male flowers that carry pollen to the male flowers of Japanese Japanese cedar and Japanese cypress. A method, wherein the compound is selected from the group consisting of (2-chloroethyl)phosphonic acid, jasmonic acid, and phytophysiologically acceptable salts or esters thereof. 4. The method according to claim 3, wherein the application of the agent to the male flowers of Japanese cedar and cypress is carried out by spraying the agent onto the surface of the male flowers. 5. The method according to claim 3, wherein the application of the agent to male flowers of Japanese cedar and cypress is carried out between 8 weeks and 1 week before the time when the male flowers start blooming. A method according to any of claims 3 or 4, wherein the agent is applied to the male flower surface as a 0.5-10% by weight aqueous solution of (2-chloroethyl)phosphonic acid. A method according to any of claims 3 or 4, wherein the agent is applied to the male flower surface as a 0.1-2% by weight aqueous jasmonic acid solution.

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