Deprecated: The each() function is deprecated. This message will be suppressed on further calls in /home/zhenxiangba/zhenxiangba.com/public_html/phproxy-improved-master/index.php on line 456
AU602792B2 - A sustained-release pheromone dispenser - Google Patents
[go: Go Back, main page]

AU602792B2 - A sustained-release pheromone dispenser - Google Patents

A sustained-release pheromone dispenser Download PDF

Info

Publication number
AU602792B2
AU602792B2 AU22297/88A AU2229788A AU602792B2 AU 602792 B2 AU602792 B2 AU 602792B2 AU 22297/88 A AU22297/88 A AU 22297/88A AU 2229788 A AU2229788 A AU 2229788A AU 602792 B2 AU602792 B2 AU 602792B2
Authority
AU
Australia
Prior art keywords
pheromone
liquid
compound
dispenser
length
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
AU22297/88A
Other versions
AU2229788A (en
Inventor
Noboru Aiba
Shigehiro Nagura
Ryuichi Saguchi
Akira Yamamoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shin Etsu Chemical Co Ltd
Original Assignee
Shin Etsu Chemical Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shin Etsu Chemical Co Ltd filed Critical Shin Etsu Chemical Co Ltd
Publication of AU2229788A publication Critical patent/AU2229788A/en
Application granted granted Critical
Publication of AU602792B2 publication Critical patent/AU602792B2/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • AHUMAN NECESSITIES
    • A01AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01GHORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
    • A01G13/00Protection of plants
    • A01G13/10Devices for affording protection against animals, birds or other pests
    • AHUMAN NECESSITIES
    • A01AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01NPRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N25/00Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
    • A01N25/18Vapour or smoke emitting compositions with delayed or sustained release

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Zoology (AREA)
  • Environmental Sciences (AREA)
  • Pest Control & Pesticides (AREA)
  • Plant Pathology (AREA)
  • Agronomy & Crop Science (AREA)
  • Engineering & Computer Science (AREA)
  • Dentistry (AREA)
  • Wood Science & Technology (AREA)
  • Birds (AREA)
  • Agricultural Chemicals And Associated Chemicals (AREA)
  • Catching Or Destruction (AREA)

Description

X
II
-rrrrrCup~ -sE~ COMMONWEALTH OF AUSTRALIA Patent Act 1952 COMP E T E S PECIF I CATION
(ORIGINAL)
Class Int. Class Application Number Lodged Complete Specification Lodged Accepted Published This documennt contains the amendC:ents mndc und- r Section 49 anJ is correct for printing 602792 Priority 17 September 1987 Related Art Name of Applicant Address of Applicant Actual Inventor/s Address for Service SHIN-ETSU CHEMICAL CO., LTD.
6-1, uhtemachi 2-chome, Chiyoda-ku, Tokyo Japan Akira YAMAMOTO, Noboru AIBA, Shigehiro NAGURA, Ryuichi
SAGUCHI
SF.B. RICE CO., Patent Attorneys, 28A Montague Street, BALMAIN 2041.
,1 Complete Specification for the invention entitled: A SUSTAINED-RELEASE PHEROMONE DISPENSER The following statement is a full description of this invention including the best method of performing it known to us/im:- The present invention relates to a sustained-release pheromone dispenser or, more particularly, relates to a tubular dispenser filled with a sex pheromone of an insectan pest and capable of sus-tainedly emitting the pheromone to the atmosphere to serve oc.o ^for the purpose of controlling the population of the nest in the field.
o" °oo It is already under practice to control the population of an ino o° sectan pest by utilizing the sex pheromone of the particular species a* of the insects. An essential requirement in this technology is to have the pheromone compound emitted to the field at a controlled 'II rate or at a uniform rate over a length of. time. Various attempts a and proposals have been made hitherto in this regard. A preparation of the pheromone dispenser suitable for such a purpose is of the type in which the pheromone compound is enclosed in a small container designated to be capable of controlling the rate of vaporization and emission of the pheromone compound contained therein.
It is an economically desirable condition that the number of the pheromone dispensers installed per unit area of the field is as small as possible insofar as the effect of the pheromone as desired can be exhibited over the field and the overall amount of the pheromone compound contained in the dispensers is as close as possible to the minimum amount of the pheromone required for exhibiting the effect of the pheromone over a length of time. It is an empirical i ^K^wte; of t It! 0 o If It t f rt I; Of ii t 0* I 0 ft
I
I
-2estimation that 1000 to 3000 pheromone dispensers should be distributed over a fields of 1 hectare wide in order that an emission rate of the sex pheromone of 1.5 to 3.0 g per day is maintained for 100 days under average meteorological conditions. This estimation leads to a conclusion that each of the pheromone dispensers should contain the sex pheromone in an amount in the range from 40 mg to 500 mg. With an object to ensure sustained releasability of the pheromone dispensers and to improve the working efficiently in the works of distributing the dispensers over the field, several pro- 10 posals have already been made in connection with the design of the pheromone dispensers as described in Japanese Patent Kokai 56- S- a'168o% 142202, 56-9705, 57-45101, 57-72904, 57-156403, 8 215367 and 61-202643. The pheromone dispensers proposed above are in a tubular form made of a plastic resin and advantageous in respect of the weatherability, sustained releasability of the pheromone coipound and long serviceable life. A problem in these pheromone dispensers is that the rate of pheromone emission cannot be fully uniform over the whole length of the service period but is decreased somewhat in the latter half period of the service life, The inventors have continuad extensive investigations to solve the above mentioned problem in a tubular pheromone dispenser prepared by enclosing from 40 mg to 500 mg of a sex pheromone compound of insect in a plastic-made capillary tube. Namely, the investigations have been undertaken with an object to uniformize the rate of pheromone emission from such pheromone dispensers over a long period of time by obviating the gradual if Ii j -3decrease of the emission rate in the latter half period of the service life when the dispensers are used by hanging on tree twigs in an orchard, tea garden and the like. The investigations have led to an unexpected discovery that the rate of pheromone emission from a tubular pheromone dispenser can be stabilized when the capillary space of the tubular dispenser is divided into several partitioned sections filled with the pheromone compound and the length of the 0o oo capillary space in each partitioned section filled with the pheromone compound is 60 mm or shorter, the overall amount of S" 10 the pheromone compound in a single pheromone dispenser being 0o o t in the range from 40 mg to 500 mg, on the base of which the present invention has been completed.
The present invention provides a sustained-release dispenser of a pheromone compound formed of a capillary tube having an average inner diameter of 0.5 to 3 mm and made of a polyethylene 0 0 0 or a copolymer of ethylene and vinyl acetate having permeability to the vapor of the pheromone compound and a liquid pheromone 0 compound in an amount of 40 mg to 500 mg enclosed in the capilo .0 0 lary tube in at least three partitioned sections of liquid columns, each of the liquid columns in the partitioned sections having a Slength L not exceeding 60 mm.
In particular, it is a preferable condition that the ratio of L/S, in which L is the above defined length of the liquid column in a unit of mm and S is the cross sectional area of the capillary space in a unit of mm 2 calculated from the average inner diameter assuming a circular cross section, is not exceeding 100.
-4- In the following, the sustained-release dispenser of a pheromone compound according to the invention is described in more detail with reference to the accompanying drawing.
Figures 1(a) and l(b) each illustrate a sustained-release pheromone dispenser according to the invention by an axial cross section and the body of the capillary tube 1 is made of a polyethylene or a copolymer of ethylene and vinyl acetate having permeability to the vapor of the pheromone compound to be enclosed therein and I has an average inner diameter of 0.5 to 3 mm. The space inside the capillary tube 1 is partitioned into at least three sections 3 by a plurality of partitions 2, 2, along the length of the tube 1. Each of the partitioned sections 3, 3, is filled with a liquid pheromone compound to form a column 4 of the liquid having a length not ex- •ceeding 60 mm. The column length L is preferably selected such that the ratio of L in mm to the cross sectional area S in mm 2 calculated from the average inner diameter assuming a circular cross section is not exceeding 100.
tThe above defined sustained-release pheromone dispenser of the present invention is characterized by the advantage that the rate of emission of the pheromone compound enclosed therein through the capillary walls can be maintained with stability over the whole length of the service life including the latter half thereof. Following is an explanation of the reason for the above mentioned advantageous characteristic with reference to Figure 2 illustrating a part of a conventional tubular pheromone dispenser by an axial cross section. As the volume of the liquid pheromone
A
C_ _IY_ U_ compound 14 in the capillary tube 11 is decreased by the emission of the pheromone compound 14 through the capillary walls, the ~j rate of pheromone emission is gradually decreased as a result of the decrease in the effective surface area available for the emission of the pheromone compound through the walls 15 because the concentration of the pheromone compound throughout the capillary walls 15 takes such a gradient that the concentration of the i pheromone compound is extremely low in the upper portion of the "j *empty space 13 not in direct contact with the liquid pheromone compound 14 even though the concentration gradient thereof in the vicinity of the liquid surface may remain unchanged.
i t In contrast thereto, the liquid pheromone compound 4 in the inventive sustained-release pheromone dispenser is enclosed in several partitioned sections 3, 3, so that, even when the overall volume of the pheromone compound remaining in the capillary I ;tube 1 is decreased by emission to the atmosphere, each of the liq- 'i uid columns 4 evenly remaining in bhe partitioned sections has its own liquid surface to keep a certain length of the capillary walls in the vicinity of the liquid surface where the concentration gradient of the pheromone compound within the capillary walls 5 remains constant. As a consequence, the effective surface area of the capillary walls available for emission of the pheromone compound Iis increased so much in proportion to the number of the partitioned sections 3, 3, contributing to the uaiformization of the rate of pheromone emission over the whole length of the service life.
-6- Accordingly, it is important in the sustained-release pheromone dispenser of the invention that the concentration gradient of the pheromone compound within the capillary walls is constant over an as long as possible length of the portion or portions of the capillary walls 5. In this regard, it is preferable that the inside space of the capillary tube 1 is partitioned along the length thereof into at least three partitioned sections and the liquid column formed of the pheromone compound enclosed therein has a length not exceeding 60 mm or, more preferably, not exceeding '50 mm.
On the other hand, it is also important that the capillary tube 1 has a limited surface area available for the emission of the pheromone compound in order to ensure sustained releasability of the pheromone compound over a long period of time. In this regard, the capillary tube 1 of the inventive tubular pheromone dispenser should have an average diameter in the range from 0.5 to 3 mm.
*Further, the overall amount of the pheromone compound enclosed in a single dispenser should be in the range from 40 mg to 500 mg in consideration of the requirements for the overall amount of pheromone emission and the number of the installed dispensers per unit area of the field.
The decrement in the column length of the liquid pheromone compound by the emission of the compound out of the dispenser is j i inversely proportional to the cross sectional area S of the capillary tube. In other words, the decrease in the length of the liquid column is larger when the cross sectional area S of the capillary tube is smaller assuming that the volume of the pheromone compound i 1d i enclosed in the capillary tube is the same. In this regard, iL is preferable in order to ensure uniformity in the rate of pheromone emission that the liquid column of the pheromone compound enclosed in each partitioned section has such a dimension that the ratio L/S of the length L in mm of the liquid column to the cross sectional area S in mm 2 does not exceed 100 or, more preferably, does not exceed The overall length of a single dispenser of the invention is preferably in the range from 80 mm to 300 mm. When the, length is too small, the effective surface area of a dispenser available for emission of the pheromone compound cannot be sufficiently large to ensure a desirable overall emission rate by distributing a number of the pheromone dispensers over unit area of the field if not to mention the problem that a tubular dispenser of a too small length can hardly be hung on a tree twig by bending. When the length is too large, on the other hand, a problem of workability is caused due to the inconvenience of handling in the hanging works of the phea 41tromone dispensers on twigs.
The capillary tube as the body of the inventive pheromone dispenser is shaped from a polyethylene or a copolymer of ethylene and vinyl acetate with optional admixture of a plasticizer, lubricant, stabilizer and the like by a conventional method of extrusion g 'j 'molding. It is also optional, if desired, to admix the resin with coloring agents, ultraviolet absorbers and the like. Further, the capillary tube prepared by extrusion molding can be subjected to a crosslinking reaction of the resin to have a network structure.
T[he wall thickness of the capillary tube also greatly influences the emission rate of the pheromone compound through i
~L
i i i
I
i i iB d )f 3 i i I i -8the wall so that the thickness should be appropriately selected in consideration of various factors. Usually, the wall thickness should preferably be in the range from 0.1 mm to 2 mm. Capillary tubes having a wall thickness smaller than above can be molded only with an extreme difficulty. Capillary tubes having a too large wall thickness are undersirable due to economical disadvantages.
The pheromone liquid enclosed in the capillary tube of the inventive pheromone dispenser can be a single compound or a mixture of two kinds or more of compounds each having an activity as a sex pheromone of a particular species of insects. It is of course optional according to need that the pheromone liquid is admixed with an antioxidant, ultraviolet absorber, coloring agent and the like.
In the following, particular embodiments of the sustained-release pheromone dispenser of the present invention are described in more detail by way of examples and comparative examples which, however, should not be construed to limit the scope of the invention in any way.
Example 1.
A pheromone dispenser was prepared by filing a capillary tube of high-density polyethylene having a length of 200 mm, inner diameter of 0.9 mm and outer diameter of 1.6 mm with 75 mg of Z-11-tetradecenyl acetate in four portions each in a partitioned section. The liquid columns of the pheromone compound each had a length of 47 mm to give an overall column length of 188 mm I t 4.
Pt I ca 4a 4 -9and the ratio L/S (mm/mm 2 of 74. The thus prepared pheromone dispenser was suspended in an air stream of 0.5 meter/second velocity at 30 °C and the rate of emission per day of the pheromone compound was determined to give the results shown by the solid Sline curve I in Figure 3.
Comparative Example 1.
The same capillary tube as used in Example 1 was filled with 75 mg of Z-11-tetradecenyl acetate without dividing into liquid columns. The length of the liquid colur" was 187 mm to give a ratio L/S in mm/mm 2 of 290. The thus prepared pheromone dispenser was subjected to the determination of the emission rate of the pheromone compound in the same manner as in Example 1 to give the results shown by the broken line curve II in Figure 3. Comparison of the results obtained in Example 1 and Comparative Example 1 1 clearly supports the conclusion that the uniformity in the emission rate of the pheromone compound can be greatly improved in the j pheromone dispenser according to the invention described in Example 1 as compared with the conventional pheromone dispenser described in Comparative Example 1.
Example 2.
A phenomone dispenser was prepared by filling a capillary Stube of high-density polyethylene having a length of 120 mm, in- Ser diameter of 1.1 mm and outer diameter of 2.2 mm with 100 mg of Z,Z/E-hexadecadienyl acetate in four portions each in a partitioned section. The liquid columns of the pheromone compound each had a length of 30 mm to give an overall column length of S1 1 120 mm and the ratio L/S in mm/mm 2 of 32. The thus prepared pheromone dispenser was subjected to the determination of the emission rate of the pheromone compound in the same manner as in Examrple 1 to give the results shown by the solid line curve III in Figure 4.
Comparative Example 2.
The same capillary tube as used in Example 2 was filled with 100 mg of Z,Z/E-hexadecadienyl acetate without dividing into liquid columns enclosed each in a partitioned section. The length of the liquid column was 120 mm to give a ratio L/S in mm/mm 2 of 130. The thus prepared pheromone dispenser was subjected to the determination of the emission rate of the pheromone compound in the same manner as in Example 1 to give the results shown by the broken line curve IV in Figure 4, Comparative Example 3.
The same capillary tubes as used in Example 1 were each filled with 70 mg to 90 mg of Z-11-tetradecenyl acetate in several portions each contained in one of the partitioned sections inside the I capillary tube as indicated in Table 1 below. The thus prepared 29 pheromone dispensers were subjected to the determination of the emission rate of the pheromone compound in the same manner as Sin Example 1. The results obtained in the measurements were used to calculate the uniformity in the rate of pheromone emission expressed by B/A, in which A is the average amount of the emitted pheromone compound per day during the period in which the amount of the pheromone compound remaining in the capillary i IS w ll V-11tube was in the range from 80% to 50% of the initial amount and B is the same value during the period in which the amount of the pheromone compound remaining in the capillary tube was in the range from 50% to 30% of the initial amount. The results of the calculation are s,'own in Table 1 together with the overall length of the liquid columns of the pheromone compound EL, overall amount of the pheromone compound contained in a pheromone dispensor W, length of a single liquid column of the pheromone corpound in a partitioned section L, number of the liquid columns enclosed in partitioned sections n and the ratio of L/S, S being 0.64 mm 2 Table 1 also includes the data in Example 1 and Comparative Example 1.
The results summarized in Table 1 supports the conclusion that high unifomity in the emission rate of the pheromone compound can be obtained when the length of each of the liquid col- Sumns does not exceed 60 mm and the ratio of L/S does not exceed 100 mm 4 i l -12- Table 1 L, mm W, mg L, mm n L/S, B/A mm- 1 187 75 187 1 290 0.87 190 77 95 2 150 0.88 225 90 75 3 120 0.88 180 72 60 3 94 0,93 188 75 47 4 74 0.95 200 80 25 8 39 0.97 0 0 09 0B 0 0 1 4% 0'0 Comparative Example 4, Capillary tubes of high-density polyethylene having an inner diameter of 0.6 mm and outer diameter of 1.3 mm were filled each with 44 mg to 50 mg of Z-11-tetradecenyl acetate in several portions each contained in a partitioned section inside the capillary tube as indicated in Table 2 below. The thus prepared pheromone dispensers were subjected to th, determination of the emission rate of the pheromone compound to calculate the uniformity B/A of the emission rate in the same manner as in Comparative Example 3 described above. The results are shown in Table 2.
13- Table 2 EL, MM W,mg L, mm n L/S, B/A 284 50 284 1 1000 0.70 285 50 57 5 200 0,84 250 44 25 10 88 0.92 The results summarized in Table 2 ;v:.upports the conclusion that the ratio of L/S shou~ld not exceed 100 mm- 1 in order to obtain suifficient uniformity in the emission rate of the pheromone compound out of the c6ispenser.
A

Claims (1)

14- THE CLAIMS "DEFINING THE INVEN'TON ARE AS FOLLOWS:- 1. A sustained-release dispenser of a liquid pheromone com- pound formed of a capillary tube having an average inner diam- eter in the range from 0.5 mm to 3 mm and made of a polyethylene or a copolymer of ethylene and vinyl acetate having permeability to the vapor of the pheromone compound and a liquid pheromone compound in an amount in the range from 40 mng to 500 mg en- closed in the capillary tube to form at least three liquid columns each contained in a partitioned section, each of the liquid coloumns in the partitioned section inside the capillary tube having a length not exceeding 60 mm. 2. The sustained-release dispenser of a liquid pheromone com- pound according to claim 1 wherein the ratic: the length of the liquid column of the pheromone compound a n to the cross sectional area S in mm 2 of the capillary tub( not exceed 100 mm-. 3. The sustained-release dispenser of a liquid pheromone com- pound according to claim 1 wherein the capillary tube has a length in the range from 80 mm to 300 mm. 4. The sustained-releast; dispenser of a liquid pheromone com- pound according to claim 1 wherein the capillary tube has a wall thickness in the range from 0.1 mm to 2.0 mm, Dated this 14th day of September 1988 SHIN-ETSU CHEMICAL CO., LTD. Patent Attorneys for the Applicant F.B. RICE CO. f It 4 t !L F
AU22297/88A 1987-09-17 1988-09-16 A sustained-release pheromone dispenser Ceased AU602792B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP23327987A JPH0780723B2 (en) 1987-09-17 1987-09-17 Sustained release pheromone dispenser
JP62-233279 1987-09-17

Publications (2)

Publication Number Publication Date
AU2229788A AU2229788A (en) 1989-03-23
AU602792B2 true AU602792B2 (en) 1990-10-25

Family

ID=16952601

Family Applications (1)

Application Number Title Priority Date Filing Date
AU22297/88A Ceased AU602792B2 (en) 1987-09-17 1988-09-16 A sustained-release pheromone dispenser

Country Status (3)

Country Link
JP (1) JPH0780723B2 (en)
AU (1) AU602792B2 (en)
FR (1) FR2620594B1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3927243A1 (en) * 1989-08-18 1991-02-21 Basf Ag DEVICE FOR COMBATING BORK BEETLES, IN PARTICULAR THE BOOK PRINTER
JP5567615B2 (en) * 2012-03-13 2014-08-06 信越化学工業株式会社 Crossed sustained release pheromone dispenser and method for producing the same
JP6561021B2 (en) * 2016-08-12 2019-08-14 信越化学工業株式会社 Rope pheromone preparation and communication disruption method using the same
USD1000579S1 (en) * 2021-05-28 2023-10-03 Shin-Etsu Chemical Co., Ltd. Insect pest control delivery device

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62122801U (en) * 1986-01-23 1987-08-04

Also Published As

Publication number Publication date
FR2620594A1 (en) 1989-03-24
AU2229788A (en) 1989-03-23
JPH0780723B2 (en) 1995-08-30
FR2620594B1 (en) 1992-05-22
JPS6475402A (en) 1989-03-22

Similar Documents

Publication Publication Date Title
EP0061192B1 (en) A sustained vapor-releasing body having excellent shape-retainability
US4017030A (en) Devices for controlled release of vapors
US4734281A (en) Method for concurrently emitting vapors of sex pheromones of different insects
KR101896743B1 (en) Structure containing volatile medicinal agent
US4527354A (en) Implantable reservoir for automatic watering of plants
US4834745A (en) Sustained-release dispenser of sex pheromone of insects
AU602792B2 (en) A sustained-release pheromone dispenser
ES2779300T3 (en) Sustained-release dispenser comprising two or more sex pheromone substances and a pest control method
US6383165B1 (en) System for achieving a controlled low emission rate for small volumes of liquid solutions
JP2915284B2 (en) Sustained release formulation
US20080011871A1 (en) Dispenser
EP0233109A2 (en) A vapor dispenser
FI60957C (en) ANORDNING FOER CONTROLS FRIGOERELSE AV ETT AVDUNSTBART MATERIAL
EP0243263B1 (en) A dispenser form for sustainedly releasing sex pheromone of insects
EP0160151A2 (en) A composite body for sustainedly releasing vapor of a vaporizable active substance and a method for the preparation thereof
JP4530804B2 (en) Sustained release pheromone formulation
EP0194934A1 (en) A tubular body for sustainedly releasing vapor of a vaporizable alcoholic substance
JPS5772904A (en) Releasing tube of sex pheromone substance
GB2042340A (en) Vapour dispensing devices
EP0537783B1 (en) Method for disruption of mating of pest insects using sustained-release sex pheromone dispenser
JPS63722Y2 (en)
JP6644516B2 (en) Fan-type volatile chemical vaporizer
JPH05201819A (en) Communication disruption method using pheromone drug
JP6146920B2 (en) Filbert worm control method
JPH065361Y2 (en) Sustained release body