JPH024567B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a soil harmful nematode control agent. Controlling soil pests and diseases in perennial crops such as fruit trees and tea plants has traditionally been an important issue, but in recent years,
In Japan, with the progress of intensive use of fields, cultivation in facilities, and special production of vegetables, problems with continuous cropping caused by harmful soil nematodes and disease-causing bacteria are becoming a problem.
In addition, it is known that harmful soil nematodes are largely responsible for fields that are unsuitable for crop cultivation, known as "dead land." Damage caused by soil harmful nematodes occurs in various ways, but
Suppression of early growth or death, and associated yield loss are common. In addition, root vegetables may become deformed or have scratches on their surfaces, drastically reducing their commercial value. Furthermore, it is impossible to continue cropping a field that has been severely damaged by nematodes, and especially in intensive agriculture like Japan, there is no room for a crop rotation system. For this reason, there is a strong demand for nematicides that are safe and inexpensive to apply. Generally, nematocides are available in the following forms: emulsions, oils, and granules. Powders are rarely used because they have many problems such as scattering of the chemicals. When using nematicides in the form of granules, they can be treated manually in pre-planting treatment, and in large areas, they can be treated using a commonly used granulator. It is reasonable and does not require time, hard labor, or special machinery. In addition, furrow treatment is the usual method for mid-piling treatment, but if it is in the form of granules, chemical treatment is easily possible. As mentioned above, granule form is the ideal form of soil treatment agent. Conventionally, the main drugs known as nematicides are halogenohydrocarbon-based fumigants, such as chloropicrin, methyl bromide, DD (1,3-dichloropropene), EDB (ethylene dibromide),
DCIP (bischloroisopropyl ether),
Examples include DBCP (1,2-dibromo-3-chloropropane). These drugs are inconvenient in handling, such as mucous membrane irritation and metal corrosiveness. Also,
While DBCP and DCIP agents do not cause phytotoxicity to some crops, most agents do.
Furthermore, most of these agents are in liquid form, require special machinery and training to use, and when applied to soil, the soil surface must be sealed with water for a certain period of time in order to be effective. In addition, in order to avoid chemical damage, it is necessary to plow after a certain period of time to dissipate the chemical into the atmosphere (degassing), which is extremely inconvenient for work. It accompanies it. Furthermore, among the products that can be made into granules, DBCP agents have been discontinued due to their toxicity to the human body and their long-term persistence in soil and river water, while DCIP agents have the problem of low nematicidal efficacy. have. In addition, contact nematicides are also used in the United States. For example, fensulfothion [0,0-diethyl 0-(4-methylsulfinyl] phenyl phosphorothioate], ethoprop (o-ethyl s,
s-dipropyl phosphorodithioate),
In addition to organic phosphorus agents such as phenamiphos [ethyl 3-methyl-4-(methylthio)phenyl (1-methylethyl) phosphoroamidate], carfofuran
(2,3-dihydro-2,2-dimethyl-7-benzofuranylmethylcarbamate), aldicarb [2
-Methyl-2(methylthio)propionaldehyde o-(methylcarbamol)oxime] and other carbamate agents. However, these contact nematicides are extremely toxic and are only permitted to be used in granule form, and moreover, are only permitted to be applied by a professional. Therefore, it is desired to develop a soil nematode control agent that is safe, easy to use, and effective. In order to solve these problems, the present inventors conducted various studies, discovered a unique action of a certain pyrrolidine compound, and completed the present invention. The present invention is a soil harmful nematode control agent containing S-methyl-N,N-tetramethylene dithiocarbamate as an active ingredient. The compound according to the present invention can be easily and inexpensively synthesized by reacting pyrrolidine with carbon disulfide and reacting the resulting dithiocarbamate salt with methyl chloride or dimethyl sulfate. The boiling point of the target compound is 156℃/9mm
Hg, and its melting point is 85-87°C. The compound according to the present invention can be used in any form such as an emulsion, a wettable powder, a granule, or a powder by mixing it with various carriers depending on the intended use. The carrier used here may be either liquid or solid,
It may also be a combination of these. Examples of solid carriers include bentonite, talc, kaolin clay, and diatomaceous earth. Examples of liquid carriers include inert organic solvents such as xylene, orthochlorotoluene, methylnaphthalene, isophorone, and kerosene. At the time of formulation, a surfactant or the like may be added in order to impart emulsifying properties and dispersibility. The appropriate active ingredient content is 5 to 30% for granules and 5 to 90% for oils and emulsions. Furthermore, the compound according to the present invention can be used not only alone, but also in combination with other agricultural chemicals such as herbicides, fungicides, insecticides, etc., or in combination with fertilizers, etc. be able to. Next, the effect of controlling soil harmful nematodes of the present invention will be explained using test examples. Test Example 1 Test against sweet potato knot nematode using tomatoes as an indicator. Example 1: Sweet potato knot nematode (meloidogyne incognita) contaminated soil grown using sweet potatoes as a host was packed in a 1/10000a pot with a height of 14 cm.
A predetermined amount of granules prepared according to the method was mixed. For comparison, commercially available nematicide granules and other control chemicals were treated in the same manner. After each chemical treatment, the pots were left for 7 days, and 10 tomato seeds were sown per pot. The test was conducted in a glass greenhouse (25-30°C), and one month after sowing, the degree of root gall parasitism, chemical damage, and stem and leaf weight were investigated. The test was repeated three times. The average values of the results are shown in Table 1. The degree of root gall parasitism and chemical damage were expressed according to the following criteria. Degree of root gall parasitism Corresponding disease index Number of root galls 0... 0 None 1... 1-25% 1-8 2... 26-50% 9-20 3... 51-75% 21-30 4... 76-100% 30 or more chemicals Harm -...No chemical damage observed±...Minor chemical damage observed+...Harmful symptoms observed...Significant harmful symptoms observed...No germination or withering

[Table] Test Example 2 Test against sweet potato knot nematodes using tomatoes as an indicator A predetermined amount of the oil solution prepared according to Example 3 and the emulsion prepared according to Example 4 were mixed with water 4 times and 8 times
Dilute it 1x, 16x, adjust it to 15 and 20 per 10a, and place it in the center of the pot, 8cm deep.
One point was injected in the area. Furthermore, each pot was sealed with 50 ml of water. For comparison purposes, the commercially available nematicide D
-D, EDB was treated in the same way, plowed for degassing on the 5th day, tomatoes were sown according to Test Example 1 on the 8th day after each chemical treatment, and root galls were removed 1 month after sowing. We investigated the degree of parasitism and drug damage. The test was repeated three times. The average values of the results are shown in Table 2.

[Table] Test Example 3 Test against Pratylenchus penetrans using burdock as an indicator.
It was packed in a 1/10000a pot with a height of 14 cm, and a predetermined amount of the granules prepared in Example 2 was mixed therein. In addition,
Comparative control drugs were treated in the same manner. Seven days after the treatment, five burdock seeds were sown per pot. The test was conducted in a glass greenhouse (25-30℃).
Fifty days after sowing, the degree of root damage, chemical damage, and total weight were investigated. The test was repeated three times. The average values of the results are shown in Table 3. The degree of damage to the roots was determined as follows based on the number of browned parts of the roots. Further, regarding chemical damage, the same procedure as in Test Example 1 was conducted. Degree of damage Corresponding morbidity index Number of browning parts 0... 0 None 1... 1-25% 1-5 2... 26-50% 6-10 3... 51-75% 11-15 4... 76-100 % 16 or more

【table】

[Table] Test Example 4 Sweet potato knot nematode control test on cucumbers in the field A predetermined amount of granules prepared according to Example 1 was applied to the entire surface of a field contaminated with sweet potato knot nematodes, where sweet potatoes had been planted in the previous crop. The soil was then immediately plowed into a mixed layer. Comparative control drugs were treated in the same manner. On the 5th day after the chemical treatment, 10 cucumber seedlings with five true leaves were planted per 4 m ² area. The test was repeated twice. Subsequent irrigation and pest control were carried out according to customary practices. The test was conducted from July 26th to September 8th, and cucumbers were harvested every five days, and the number and weight of the cucumbers were measured. On September 8th, each plant was excavated and the extent of parasitic root galls and the weight of stems and leaves were investigated. The average values of the results are shown in Table 4.

【table】

[Table] As described above, S-methyl-N,N according to the present invention
- Tetramethylene dithiocarbamate exhibits high control effects against sweet potato knot nematodes and northern red cabbage nematodes, which cause severe damage to crops. Furthermore, it has the excellent feature of not causing chemical damage to tomatoes, cucumbers, burdock, etc. Formulation examples are shown below. Parts in the text are parts by weight. Example 1 Granules S-methyl-N,N-tetramethylene dithiocarbamate 10 parts Granular diatomaceous earth (10 to 16 mesh) 90 parts The above active ingredient was impregnated into granular diatomaceous earth to prepare the granules of the present invention. Example 2 Granular diatomaceous earth 70 parts Bentonite 25 parts Rapizole B-80 (dispersant, Nippon Oil & Fats Co., Ltd. trademark)
Water was added to 5 parts or more, mixed, and granulated using a conventional granulation method. For 85 parts of this granular carrier, S-methyl-
The pellets were impregnated with 15 parts of N,N-tetramethylene dithiocarbamate to prepare granules of the present invention. Example 3 Oil Agent 10 parts of S-methyl-N,N-tetramethylene dithiocarbamate and 90 parts of o-chlorotoluene were mixed and dissolved to prepare an oil agent of the present invention. Example 4 Emulsion S-methyl-N,N-tetramethylene dithiocarbamate 80 parts xylene 10 parts Solpol 800A (emulsifier, trademark of Toho Chemical Co., Ltd.)
At least 10 parts were mixed and dissolved to prepare the emulsion of the present invention.

Claims (1)

[Claims] 1. A soil harmful nematode control agent characterized by containing S-methyl-N,N-tetramethylene dithiocarbamate as an active ingredient.