JPH0530802B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a soil treatment method for treating soil in and around a construction area of a building by spraying, mixing, etc. with a termiticide. Termites prefer sunny, humid, and relatively warm places, and they feed on the wood of kitchens, bathrooms, washrooms, and toilets, causing severe damage to buildings. In recent years, damage has also spread to building materials inside reinforced concrete buildings and underground communication cables. In our country, damage caused by Japanese termites and Japanese termites is especially significant. In general, house termites build their nests underground, and from there they search for wood to feed on, extending their ant trails. Also, since it has the property of trapping water, dry wood materials are also susceptible to feeding damage, causing severe damage. On the other hand, Yamato termites have the characteristic that they make their nests in places where they have suffered feeding damage.
Compared to the Japanese termite, the damage caused is slight, but the occurrence frequency is high and most termite damage is caused by the Japanese termite. Since both types of termites move through the soil, termite control involves applying termite control treatment directly to the damaged wood.
Soil treatment methods include spraying or mixing chemicals into the soil over a cm area. The amount of chemicals per unit treatment area used in this soil treatment is usually higher than in the case of wood treatment methods because the chemicals penetrate deep into the ground, and among soil treatment methods, the amount of chemicals used per unit treatment area is higher than in the case of wood treatment methods. The amount of the drug is larger in the mixing method in which the drug is added. Chlordane, which has traditionally been used in soil treatment methods, has a proven track record in long-term field tests. On the other hand, like DDT, γ-BHC, aldrin, and deirdrin, chlordane is an organochlorine agent, so when used in high concentrations, chlordane is highly toxic to humans and has an odor, which can lead to concerns about worker safety and rainfall. There were problems with environmental pollution due to runoff. An object of the present invention is to provide a soil treatment method that is highly safe for humans and livestock, does not cause problems of environmental pollution, and has a long-term termite prevention effect. The inventors proposed the following formula: A drug containing O,O-diethyl-O-2,3-dihydro-3-oxo-2-phenyl-6-pyridazinyl phosphorothioate (hereinafter abbreviated as phosphorothioate) as an active ingredient is applied to the soil. It has been found that by containing it, the effect of selectively repelling termites can be obtained for a long period of time. This phosphorothioate is known as a low toxicity organic agent effective as an agricultural insecticide. for example,
Breuil's U.S. Patent No. 2,759,937 states that it is effective as an insecticide and acaricide;
No. 14568 and Japanese Patent Publication No. 52-46288 describe its use for controlling the Japanese leafhopper and Japanese leafhopper. Conventionally used γ-BHC, DDT, Deildrin, etc. are highly toxic to humans and animals, such as accumulative, persistent, and carcinogenic, and are likely to cause environmental pollution, so their use is prohibited. In addition, the acute toxicity LD50 value of the currently used chlordane is 280-570 when administered orally.
mg/Kg (rat), dermal 530-700 mg/Kg (rat), and for fish toxicity, TLm is 48 hours.
High at 0.26ppm (carp) and 0.1ppm (himedaka). In contrast, the toxicity of the present phosphorothioate contained in the treatment agent used in the soil treatment method of the present invention is extremely low, for example, the acute toxicity LD50 value is 769 mg/orally.
Kg (rat), 2300 mg/Kg (rat) transdermally. No abnormalities were observed in subacute or chronic toxicity tests, and carcinogenicity and mutagenicity tests were also negative. Regarding fish toxicity, the TLm value at 48 hours
This phosphorothioate has extremely low toxicity to livestock and fish, with concentrations such as 12ppm (carp) and 10ppm (medaka). The treatment agent used in the soil treatment method of the present invention can be used in various liquid or solid formulations together with various carriers and adjuvants, as well as commonly used soil treatment agents.
For example, it can be used as an emulsion or powder. Other insecticides can also be added. When actually applying the soil treatment method of the present invention,
Mixing and spraying methods can be used as well as conventional soil treatment methods. The soil treatment method of the present invention takes different application forms depending on the type and nature of the soil, the characteristics of the climate of the region, the type of termites, etc. Regarding the application amount, if this phosphorothioate is used in the mixed method,
g/m ³ or more, preferably 5 g/m ³ or more; in the case of spraying, it is sufficient if the soil contains 1 g/m ² or more, preferably 5 g/m ^{2 or} more; there is no upper limit, but especially for large-scale application. Not necessary, and for health and safety reasons, the mixing method requires less than 100g/ ^m3 , and the spraying method requires less than 100g/m3.
m ² or less is preferable. Conventional soil treatment with chlordane requires 60 to 100 g/ ^m2 or more by spraying method,
The method of the present invention can achieve the same or better objectives with much lower doses. In addition, in soil treated with chlordane, other animals besides termites are killed indiscriminately;
Since the long-term effectiveness of the soil treatment method of the present invention is mainly due to its repellent action against termites, it is an excellent soil treatment method that has less impact on other animals and the ecosystem, and causes less environmental pollution. Examples will be described below, but the blending ratio of the present phosphorothioate, the auxiliary components, and the amount added thereof are not limited thereto. Example 1 A hole with a diameter of 15 cm and a depth of 30 cm was dug in an area where termites live outdoors, and the excavated soil was mixed with the present phosphorothioate 40% emulsion (mixture), the present phosphorothioate 50% powder (mixture), and Sumithion 50% emulsion ( (manufactured by Sumitomo Chemical Industries), Chlordane 50% emulsion (compound), Natsuku 15% emulsion (manufactured by Nissan Chemical Industries), Visit 50
% emulsion (manufactured by Nippon Tokushu Nogyo Co., Ltd.) and the diluted solutions of each of them were mixed, red pine sapwood (30 x 30 x 350 mm) was buried in each test plot (repeated 5 times), and one year later,
A survey was conducted five years later. The amount of drug was 5/m ² , and for powders it was 10 g, 4 g, and 2 g/m ² . In addition, the test areas were randomly arranged. In addition, the above diluted chemical solution was sprayed on the soil (15 cm in diameter), red pine sapwood (30 x 30 x 150 mm) was placed, and the same survey was conducted 1 year and 5 years later. The formulation example is as follows: Emulsion phosphorothioate 40 parts Surfactant 10 parts 40 parts Total 100 parts Examples of use are as follows: This phosphorothioate emulsion 400-fold dilution, 1000-fold dilution, 2000-fold dilution Sumithion emulsion 500 1250 Visituto emulsion 500 1250 Chlordane emulsion 50 125 Natsuk emulsion 150 375 The results are shown in Tables 1 and 2.

【table】

【table】

[Table] The phosphorothioate is effective in small amounts for at least 5 years. Pesticides such as Sumithion cause damage even after one year, and chlordane is only effective when used in large quantities (approximately 25 to 50 times more than this phosphorothioate), and the use of such large quantities causes ecological problems as described below. This is a systematic problem. Example 2 In the second year of Example 1, a portion of each chemically treated soil was placed in a glass jar, and three slugs, millipedes, and pill bugs were placed therein. 25℃±2
The test insects were left in a thermostat at 75% RH and the conditions of the test insects were observed after 48 hours. For comparison, we also conducted an experiment on termites (100 individuals) using soil immediately after treatment and two years later. The results are shown in Table 3.

[Table] As can be seen from this result, the soil containing this phosphorothioate has no killing effect on any animals and is considered harmless to the ecosystem, similar to pesticides such as Sumithion. Although chlordane-treated soil is effective against termites,
It also indiscriminately kills slugs, millipedes, and pill bugs, which has a negative impact on the ecosystem. Example 3 Using the chemical-mixed soil used in Example 1 that had been outdoors for two years, an experiment was conducted to examine the termite repellent effect of each chemical-treated soil using the apparatus shown in FIGS. 1 and 2. As shown in Figs. 1 and 2, the termite repellent effect test device consists of a rectangular parallelepiped container 11, a partition plate 1 whose upper half is made of a glass plate, and whose lower half is made of a perforated acrylic plate.
2. Untreated soil is placed in a chamber 13 on one side of the partition plate, and treated soil is placed in a large chamber 14 on the other side. Red pine sapwood 15 in treated soil chamber 14
(50 x 50 x 150 mm) and put termites into the untreated soil chamber 13. The container 11 is covered with a glass plate 16. Chemically treated soil should be kept at 25℃±2℃ in advance.
It was kept in a thermostat at 75% RH for one week. 100 termites were placed in the untreated soil section of a termite repellent effect experimental device, and the device was heated to 25°C ± 2°C.
It was left in a thermostat at RH75% for 10 days. Thereafter, the untreated soil and the treated soil were taken out and sieved to observe whether termites were alive or dead in each treated area and whether they were damaging the red pine sapwood. The termites used were Yamato termites and Japanese termites collected in the field. The results are shown in Table 4.

[Table] Severe feeding damage The results show that the main effect of this phosphorothioate-treated soil against termites is its repellent effect. In other words, the main effect at the beginning is termite-killing effect, but this does not last long and termite-killing effect disappears after two years, and after that, the termite-repellent effect makes it possible to use wood for a long period of time. It has become clear that it protects people from damage. Example 4 Four houses in Yatojima, Isesaki City, Gunma Prefecture were divided alternately into soil treatment areas and non-treatment areas with the present phosphorothioate, and a damage survey was conducted four years later. The individual areas surveyed were the kitchen and bathroom. Figure 3 shows the layout and floor plan of the house. The results are shown below.

[Table] (Note) The denominator indicates the number of surveyed houses, and the numerator indicates the number of damaged houses.

[Brief explanation of the drawing]

FIGS. 1 and 2 are a schematic plan view and a cross-sectional view of the termite repellent effect experiment apparatus, respectively, and FIG. 3 is a layout and floor plan of the house where the soil treatment experiment was conducted.

Claims (1)

[Claims] 1 O,O-diethyl-O-2,3-dihydro-
A liquid or powdered drug containing 3-oxo-2-phenyl-6-pyridazinyl phosphorothioate as an active ingredient is applied to the soil under the floor of a house so that the active ingredient is 2 g/m ³ or more in the soil. A soil treatment method characterized by controlling termites through a mixed treatment. 2 O,O-diethyl-O-2,3-dihydro-
Apply a liquid or powdered drug containing 3-oxo-2-phenyl-6-pyridazinyl phosphorothioate as an active ingredient to the soil under the floors of houses so that the active ingredient is 1 g/m3 or ^more on the soil surface. A soil treatment method characterized by controlling termites by a mixed treatment.