JPH10152408A - Insect fumigant for timber pest and method of fumigating timber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new insect fumigant for timber pest which can treat on a large-scale at a small amount in a short time by dissolving methyl isothiocyanate which is solid at ordinary temperature into a specific gas. SOLUTION: This fumigant prepared by dissolving methyl isothiocyanate into a liquefied high pressure gas. As the liquefied high pressure gas, carbon dioxide, propane, 1,1,1,2-tetrafluoroethane and methyl bromide can be illustrated. Especially, mixed gases of liquefied carbon dioxide or carbon dioxide and other liquefied high pressure gases are preferable. When liquefied carbon dioxide is used, methyl isothiocyanate and liquefied carbon dioxide are mixed in proportions of 2-95wt.% and 98-5wt.%, respectively. Timbers are fumigated with this fumigant by jetting the active ingredients in the treating room by utilizing the pressure of the liquefied high pressure gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fumigant for wood insect pests and a method for fumigating wood. More specifically, the active ingredient methyl isothiocyanate (CH ₃ N = CS;
Hereinafter, it may be abbreviated as MITC. ) Is dissolved in a liquefied high-pressure gas, and a fumigant for insect pests of wood and a method of fumigating wood using the fumigant for insects.

[0002]

2. Description of the Related Art Agricultural and forestry products imported into Japan are always inspected from the viewpoint of plant protection, and it is obligatory to eliminate harmful flora and fauna by fumigation as necessary. Invasive breeding is being prevented. For imported timber, from the same point of view, the standards for disinfection methods are set forth in the Imported Wood Quarantine Guidelines, and disinfection is implemented. For this reason, imported wood treatment methods that are currently in practical use include treatment methods using chemicals such as methyl bromide, physical methods of submerging in water, and methods combining them. The most frequently used method is fumigation using methyl bromide. Since this method is extremely simple and has a certain effect, it is widely used in practice. However, methyl bromide is one of the substances causing ozone layer depletion, and in recent years there has been an increasing movement to restrict the use of methyl bromide from the viewpoint of protecting the global environment.

Further, as a technique related to the present invention, MI is decomposed by dispersing a
There are pesticides that generate TC. It is used as a fumigation treatment for pine wood infested with pine wilt insects (pine pine sawyer larvae and pine wood nematodes). The dosage in this case is 0.5-1.0 liters / m ³ and requires a coating period of 1-2 weeks. However, since it is different from the agent that administers the MITC gas itself, it takes a long time before the MITC gas is generated after the liquid is sprayed, and the covering period is long. Is considered unsuitable for processing. As described above, pesticides that utilize the excellent insecticidal effect of MITC are already on the market, but are not known at all as gas preparations intended for fumigation on a large scale and in a short time.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to eliminate the use of ozone depleting substances such as bromine-containing compounds or to reduce the amount of use, and to achieve a large-scale process in a short time in a small amount. It is an object of the present invention to provide a new fumigant for wood pests that can be treated and a method for fumigation of wood.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have studied various compounds which have not been used as a fumigant for imported wood so far. It was confirmed that MITC (melting point: 35 to 36 ° C., boiling point 119 ° C.), which was considered unsuitable as a fumigant because it was difficult to gasify in that case, dissolved well in a liquefied high-pressure gas such as carbon dioxide. When this solution is sprayed into a fumigation coating from a high-pressure container (gas cylinder) using the pressure of a liquefied high-pressure gas, MITC is sprayed as fine-grained crystals. The inside is filled with gas. As a result,
By fumigation for 48 hours, insects penetrating the subcutaneous wood and in the wood can be controlled, and it has been confirmed that they can be sufficiently used as a fumigant for imported wood, and the present invention has been completed. Was.

That is, the present invention provides 1) a fumigant for disinfesting wood pests obtained by dissolving methyl isothiocyanate in a liquefied high-pressure gas; 2) a liquefied high-pressure gas comprising carbon dioxide, propane, 1,1,
The fumigant for wood insect pests according to the above 1, which is selected from one or more of 1,2-tetrafluoroethane, methyl bromide, and sulfuryl fluoride; 3) The liquefied gas is liquefied carbon dioxide or other liquefied carbon dioxide. The fumigant for wood insect pests and insects according to the above 2, which is a mixed gas with a high-pressure gas, 4) the liquefied gas is liquefied carbon dioxide, and the mixing ratio of methyl isothiocyanate and liquefied carbon dioxide is 2 to 95% by weight of the former; The fumigant for killing wood pests according to the above 3, which is 98 to 5% by weight of the latter, 5) The mixing ratio of methyl isothiocyanate and liquefied carbon dioxide gas is 10 to 50% by weight of the former and 90 to 50% by weight of the latter. 4) A fumigant for insect pests and insects according to 4), and 6) Liquefied carbon dioxide gas or methyl isothiocyanate dissolved in liquefied carbon dioxide gas and other liquefied high-pressure gas using the pressure of the liquefied gas. A wood fumigation method is provided, wherein the wood is fumigated by being injected into a processing chamber.

Hereinafter, the present invention will be described in detail. In the present invention, methyl isothiocyanate used as an active ingredient of the fumigant has a melting point of 35 to 36 ° C., as described above.
A normally irritating substance which is solid at room temperature with a boiling point of 119 ° C,
It has a bactericidal and insecticidal action and is widely used as a soil treatment agent for agriculture. However, the vapor pressure is low for use as a fumigant. Then, the present inventors examined the solubility of MITC in various liquefied high-pressure gases. As a result, MIT
C is carbon dioxide gas (the pressure in the liquefied container is about 50 kg / c
m ² ), methyl bromide (also about 1 kg / cm ² ), propane (also about 10 kg / cm ² ), 1,1,1,2-
Dissolves well in tetrafluoroethane (also about 6 kg / cm ² ) and sulfuryl fluoride (also about 18 kg / cm ² ). Discharged MITC can be discharged at the pressure of liquefied high-pressure gas. It was sprayed and dispersed in the form of fine particles, facilitating rapid vaporization of MITC, and it was confirmed that it could be used for the purpose of quarantine fumigation. Among them, liquefied carbon dioxide is inexpensive, inactive, stable and has almost no toxicity, so it can be expected to exhibit only the medicinal properties inherent in the active ingredient, it is nonflammable, and it is used in large spaces with high pressure and high space It is very preferably used because it has features such as being sprayable.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to various test examples and examples. Test Example 1: Solubility of MITC for Various Gases After a certain amount of MITC was weighed into a pressure-resistant glass bottle, various high-pressure gases described in Table 1 below were filled, and the solubility was visually confirmed, and the following results were obtained. I got

[0009]

[Table 1] Types of high-pressure gas Soluble carbon dioxide Soluble Methyl bromide Soluble Propane Soluble 1,1,1,2-tetrafluoroethane Soluble Sulfuryl fluoride Soluble Soluble compressed nitrogen Insoluble

Test Example 2 The following tests were conducted to examine the effects of the discharge pressure and the MITC concentration on the particle size of the discharge MITC. MITC was dissolved in liquefied carbon dioxide by changing the concentration to a high-pressure cylinder, and MI was sprayed from a spray nozzle with a diameter of 0.5 mm.
The TC particle size was measured using a Malvern particle size measuring device. Table 2 shows the results.

[0011]

[Table 2] MITC concentration Pressure (kg / cm ² ) MITC particle size (%) (25 ° C.) (μm) 10 about 60 1-3 30 about 54 2-550 about 494-10

From Table 2, it can be seen that the lower the concentration of MITC (the higher the gas pressure), the more particulate MITC is produced. In practice, the MITC content is 2 to 98% by weight.
, But is preferably 10 to 50% by weight, more preferably 20 to 40% by weight. If the concentration is too high, a sufficient injection pressure cannot be obtained, the particle size of MITC increases, and the effect of volatile evaporation decreases. If the concentration is too low,
A large amount of carbon dioxide is required to obtain the desired effect, which is not efficient.

Test Example 3 The following test was conducted to determine the amount of a drug required to kill various insects using MITC. (i) Larval insecticidal test in pine sawyer wood: A preliminary test was carried out by the following method in order to know the amount of the chemical required when dissolved in carbon dioxide. In other words, pine wood (with bark, about 30
m, diameter 8 to 10 cm) in a 30 liter sealed container (desiccator), into which a beaker in which a predetermined amount of the MITC raw material is dissolved in 10 ml of ethanol is put, and 15 ± 1 ° C.
And left at 25 ± 1 ° C. for 24 hours, and 7 days after opening, the larvae were judged to be alive or dead. The results are shown in Table 3 together with the results of a control in which only 10 ml of ethanol was vaporized.

[0014]

[Table 3] Active ingredient 15 ° C, 24 hours 25 ° C, 24 hours (g / 30l) Number of live insects Number of dead insects Number of live insects Number of dead insects 5.0 0 23 3.0 66 6 1.0 0 15 0.40 12 0.1 150 0 Control 110

From Table 3, the amount of MITC (amount of vaporization) required for fumigation differs depending on the temperature of the treatment area.
It can be seen that the larvae in the wood can be completely killed at a dosage of 1.0 g drug substance / 30 l when the temperature is around ° C.

(Ii) Tricholoma pine beetle ovicidal test: Three pine pine wood (with bark) having a length of 30 cm and a diameter of 6.7 to 7.4 cm are placed in a 30-liter sealed container (desiccator). Into a beaker prepared by dissolving a predetermined amount of the MITC drug substance in 10 ml of ethanol.
Leave at 1 ℃, 15 ± 1 ℃ and 25 ± 1 ℃ for 24 hours,
After fumigation, it was opened and stored at a constant temperature of 25 ° C. for 10 days, and then the presence or absence of hatching was examined. The result is ethanol 10
The results are shown in Table 4 together with the results of the control in which only ml was evaporated.

[0017]

[Table 4] Temperature Protozoa Live larvae Dead larvae Unhatched eggs Unknown Correction ^* (g / 30l) Mortality% 0.02 310 147 77 515 ° C 0.04 5 1 164 88 92 0.08 0 2 143 98 100 Control 685 118 86 00.02 64 0 79 147-15 ° C. 0.04 71 123 96 88 0.08 00 166 71 100 Control 56 0 73 89 0 0.02 6 2 110 69 92 25 ° C. 0.04 0 1 122 38 100 0.08 0 5 93 46 100 Control 58 0 30 100 100 0

* Adjusted mortality is the survival rate (%) of the drug-treated group (B) and the survival rate (%) of the drug-untreated control (A)
And was calculated from the following equation. Survival rate (%) = [(live larva) {(live larva) + (dead larva) + (unhatched egg)}] × 100 Corrected mortality (%) = [{(A)-(B)} (A)] ×
100

From Table 4, it can be seen that the amount of MITC required for fumigation of the eggs (amount of vaporization) is much smaller than that of the larvae, and that the effect of 0.1 g / 30 l at a low temperature of 5 ° C. is sufficient. It can be seen that it can be obtained.

(Iii) Fumigation test of weevil: Red pine wood which is left outdoors and in which weevil etc.
Put two bottles each in zero 20-liter containers (container numbers: 1 to 8, keeping the temperature in the container at 25 ° C.). A metal plate equipped with a device for electrically heating is installed at the lower part of the entrance of each 20-liter container, the temperature is set to 50 to 60 ° C., and a predetermined amount of the MITC raw material is placed in a beaker, and placed thereon. After complete vaporization, the temperature in the vessel was kept at 25 ° C. and kept for 24 hours and steamed. The results are shown in Table 5 together with the results of the control (container number 9 to 10) in which the MITC drug substance was not treated.

[0021]

[Table 5]

As is evident from Table 5, insects parasitic on the subcutaneous tree, such as weevil larvae and ants, all died in the treatment group at a dose of about 0.54 g to 1.00 g / 20 liters. Therefore, it can be seen that the insects under the tree are effective at a lower dose than the larvae of the pine sawyer wood. The weevil is a weevil weevil, a weevil weevil, a bark beetle is a grub beetle, and a beetle is a beetle beetle, etc.

(Iv) Fumigation test of the larvae of the weevil weevils: pine logs (approximately 3 in length) infested by larvae of the weevil weevil
(0 cm, diameter: 8 to 10 cm) are placed in a 20-liter container with the bark attached. In a 20-liter beaker, a predetermined amount of the original MITC is dissolved in ethanol, and a filter paper is set up and vaporized. This was put in a 25 ° C. constant temperature oven, and the effect was judged 24 hours later. Table 6 shows the results.

[0024]

[Table 6] MITC (g) Larva container number in the material Treatment amount Vaporization amount Life and death Total mortality% 1 0.27 0.25 0 20 20 100 2 0.31 0.28 0 17 17 100 1003 0.54 0.51 0 32 32 100 4 1.08 1.02 0 25 25 100 5 2.15 2.13 0 22 22 100

From the results of Tables 5 and 6, it can be seen that the method using methyl isothiocyanate according to the present invention is sufficiently effective as a method for fumigation treatment of imported wood.

Examples 1-2 Based on the results of the above test examples, an insecticidal test was performed on the larvae of the Japanese pine sawyer, Mantis beetle. The specific procedure is as follows. As shown in the perspective view in FIG. 1, the inner volume was about 0.7 m ³ using a vinyl-coated iron pipe (diameter 2.5 cm).
(100cm x 100cm x 70cm) Make a frame, store a certain number of lumber, and then put the outside to 0.2m thickness
m, and sealed. The timber to be stored in the test room has a diameter of 10 to 20 cm and a length of 9 as shown in FIG. 2 (Example 1) and FIG. 3 (Example 2).
The pine of 0 cm 18 present (Figure 2) and present 17 (Figure 3) and (covering the material volume of about 0.3 m ^3), a carbon dioxide gas formulation containing MITC 30% by weight piercing the nozzle of the gas cylinder in the coating The injection time was changed, and the injection port was sealed. The injection time and dose were as shown in Table 7. The temperature of the test room was generally kept at 25 ° C. (the maximum temperature difference was 6 to 7 ° C.). 1 to No. The survival of larvae was determined for 9 pine woods. Table 8 shows the results.
Table 9 shows the results obtained by summarizing the data.
Shown in

[0027]

[Table 7] Example Injection time Dosage amount MITC amount Larval larva Larvae mortality number sec g / m ³ g / m ³ life and death% Example 1 16 124.3 37.3 0 146 100 〃 2 31 251.4 75.4 0 148 100

[0028]

Table 8 Results of Example 1: Wood pine sawyer beetle larva No. Number of live insects Number of dead insects 209 220 430 440 225 250 156 0 770 168 0 199 0 20 Total 0 146

[0029]

Table 9 Results of Example 2: Wood pine sawyer beetle larva No. Number of live insects Number of dead insects 10 14 20 19 030 174 0 24 550 0 16 600 12 70 150 890 0 15 990 16 Total 0 148

From Tables 7-9, the 30% liquefied carbon dioxide formulation was
It can be seen that the larvae of the Japanese pine sawyer sword beetle were completely killed regardless of the location of the pine wood when spray fumigation treatment was performed in the test chamber at 37.3 g / m ³ or more.

Example 3 [Test Material] (1) Mizunara wood: A Mizunara wood which was collected in Yamagata prefecture just before the test (summer season) and in which parasitoid beetles and its close species, Parasitoid bark beetles are infested. In the following results, the two species are not distinguished and are tabulated as Pseudococcidae. (2) Scots pine I: Scots pine infested with file bark beetle. (3) Japanese red pine lumber II: Adult Japanese larch bark beetle collected from Japanese red pine wood was spawned on Japanese red pine wood, and it was confirmed that it had grown to the last instar larva and pupa. (4) Japanese cedar wood I: Japanese cedar wood that was left at the cedar forest edge in Ibaraki Prefecture and infested with Japanese cedar beetles. (5) Japanese cedar wood II: Spawning adult Japanese cedar beetles collected in Tochigi Prefecture, and hatching larvae on a 30 cm long Japanese cedar wood in May
Eight animals were inoculated and tested after confirming that they grew into terminal larvae and pupae.

The above five kinds of test materials 16 shown (timber volume Total: 0.11 m ³⁾ housed in fumigation of internal volume 0.5 m ³ and 30 the MITC insert the dosing nozzles of the gas cylinder to the fumigation upper dosing port The carbon dioxide formulation containing weight% was injected for 27 seconds. The dosage of the formulation is 89.0 g / 0.5 m ^3, which, as the MITC corresponds to a dose of 53.4 g / m ^3. Immediately after the chemical injection, white crystals of MITC were observed to adhere to the surface of the wood, but all of them sublimated 2 hours after the injection. Twenty-four hours after the injection, the gas in the fumigation chamber was exhausted outside using an exhaust device, and then the fumigation chamber was opened and allowed to stand until the next day. Thereafter, the wood was stored in the breeding room. Red pine lumber II
(Test insect: Japanese larch beetle)
At week 5, cedar wood I and II (test insects: test insects: file beetle) and red pine wood I (test insects: file bark beetle) at week 5
At eight weeks, the survival of larvae, pupae, and adults under the tree and in the timber was determined for eight weeks. Table 10 shows the results. In each case, the wood in which the insects were parasitized under the same conditions as the test material was kept untreated in the breeding room, and it was confirmed that the same kind of insects survived by splitting the wood. .

[0033]

[Table 10]

As shown in the results in Table 10, 53.4 g /
At a dose of m ³ , 100% of all subcutaneous borers were killed. When only subcutaneous insects are targeted, the dose can be further reduced. The reason why an eight-week period was set for the judgment of the cedar wood is that it is difficult to judge whether the pupae are dead or live for the cedar and the female cedar. Those that have not yet emerged after a period of 8 weeks can be determined to have died during the pupa stage. Also,
The wood beetle (Mizunara wood) has a very large number of individuals per timber volume, especially in the sapwood part of the test material, but some individuals extend to the deepest part (near the heartwood). I have. In the fumigation test with the MITC ethanol preparation performed in advance, it was found that the individual near the heartwood died after a lapse of some time from opening depending on the dose, so that accurate measurement was also performed in this example. Five weeks after opening, survival was judged.

The reason why the mortality rate of the wood beetle near the heartwood increases during storage after opening is considered to be that the drug adsorbed in the wood exhibits an effect during the storage period, but died with the passage of days. Larvae and the like discolor black and decay, which may be related to changes in environmental conditions in the wood. For example, since MITC is also known to have a bactericidal effect, it is considered that the nutritional status of larvae and the like is reduced by the action of MITC on ambrosia fungi that feed on larvae. In addition, since the adult beetle has a habit of taking care of larvae and the like, it is conceivable that when an adult in the wood dies, the growth of the larvae or the like is hindered and death occurs.

In the above examples, tests were conducted on wood-penetrating insects. However, if the treatment was carried out in the same manner as in these examples, control of pests as shown in Test Examples 3 (iii) and (iv) or other pests was carried out. The fumigant of the present invention is also effective.

[0037]

According to the present invention, in a closed room containing wood,
A method of fumigating wood by spraying a fumigant for disinfestation of wood pests obtained by dissolving methyl isothiocyanate in a liquefied high-pressure gas under the pressure of the liquefied high-pressure gas and introducing it in fine particles to efficiently vaporize the methyl isothiocyanate and fumigation the wood. The present invention provides a fumigation method and a fumigant for wood that does not use a substance causing ozone layer depletion in place of a bromine-containing compound or the like, or that reduces the amount of wood used.

[Brief description of the drawings]

FIG. 1 is a perspective view of a test chamber in which a medium-scale test using a fumigant for insect pest control of liquefied carbon dioxide gas-dissolved wood of the present invention was performed.

FIG. 2 is a diagram showing the arrangement of wood in a medium-scale test number 1 using the fumigant for harmful insect pests of liquefied carbon dioxide dissolved wood of the present invention.

FIG. 3 is a diagram showing the arrangement of wood in a medium-scale test No. 2 using the fumigant for insecticidal pests of liquefied carbon dioxide dissolved wood of the present invention.

[Explanation of symbols]

 1-9 Test material number

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Satoshi Itabashi 1-2-2 Kiyokucho, Kuki-shi, Saitama Liquefied Carbonated Inc. (72) Inventor Hiroyuki Miyachi 1-2-2 Kiyokucho, Kuki-shi, Saitama Liquefied Carbonated Inc. (72) Inventor Bunshiro Tomita 1-2-2 Kiyohakucho, Kuki-shi, Saitama

Claims (6)

[Claims] 1. A fumigant for disinfecting wood pests obtained by dissolving methyl isothiocyanate in a liquefied high-pressure gas. 2. The liquefied high-pressure gas is carbon dioxide, propane,
1,1,1,2-tetrafluoroethane, methyl bromide,
The fumigant according to claim 1, wherein the fumigant is selected from one or more of sulfuryl fluoride. 3. The fumigant of claim 2, wherein the liquefied gas is liquefied carbon dioxide or a mixture of carbon dioxide and another liquefied high-pressure gas. 4. The insect pest according to claim 3, wherein the liquefied gas is liquefied carbon dioxide, and the mixing ratio of methyl isothiocyanate and liquefied carbon dioxide is 2 to 95% by weight of the former and 98 to 5% by weight of the latter. For fumigants. 5. The mixing ratio of methyl isothiocyanate and liquefied carbon dioxide is 10 to 50% by weight of the former, and 90 to 5% by weight of the latter.
The fumigant for wood insect pests according to claim 4, which is 0% by weight. 6. A wood characterized in that liquefied carbon dioxide gas or methyl isothiocyanate dissolved in liquefied carbon dioxide gas and another liquefied high-pressure gas is injected into a processing chamber using the pressure of the liquefied gas, and the wood is fumigated. Fumigation method.