JPH0124764B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to 0,0-
Dimethyl 0-2,6-dichloro-4-methylphenyl phosphorothioate (hereinafter abbreviated as tolclofos-methyl) and 2-(4-thiazolyl)benzimidazole (hereinafter abbreviated as thiabendazole) or methyl-2-benzimidazole carbamate (hereinafter abbreviated as thiabendazole) To provide a novel agricultural and horticultural fungicide that exhibits remarkable synergism particularly against snow rot, which is characterized by containing as an active ingredient a mixture of two types of fungicides with carbendazine (abbreviated as carbendazine). It is something. Triclofos methyl

【formula】 Thiabendazole

【formula】 carbendazine

[Formula] Recently, with the change in Japan's basic agricultural policy to "reduce the overproduction of rice and increase the production of other crops," a movement to reduce rice paddies has been developed, and the crop rotation of wheat, soybeans, etc. has been rapid. is progressing. however,
In order to stabilize the cultivation of autumn-sown wheat in the Hokkaido and Tohoku regions, which are areas with winter snowfall, it is extremely important to control wheat snow rot, which is a soil-borne disease. In particular, this disease is associated with four types of diseases caused by different pathogens: red snow rot (Fusarium nivale), snow rot large-grained sclerotia (Sclerotinia borealis), snow rot black small-grained sclerotide (Typhula ishikariensis), and snow rot. In reality, there are almost no fungicides that are effective against these various diseases and are highly safe, since they include various diseases caused by brown small-grained sclerotia (Typhula incarnata). Therefore,
The development of new fungicides and control techniques that can simultaneously control this disease in a labor-saving manner is urgently needed to promote and stabilize wheat cultivation in paddy fields. In view of these circumstances, the present inventors tested a large number of drugs and conducted extensive studies at the indoor screening and field test level. As a result, it was found that a new fungicide prepared by blending tolclofos-methyl with the known thiabendazole or carbendazine is extremely effective against the above-mentioned diseases. Torclofos-methyl, one of the active ingredients of the present invention, is a soil fungicide disclosed in Japanese Patent Publication No. 51-20571, and is effective against cucumber seedling blight (Rhizoctonia solani) and radish yellowing (Fusarium oxysporum f. It is known to be effective against bacteria such as .sp. In addition, thiabenzole is
−23274 Publication, “Pesticide Handbook 1976 Edition”
(Published by Japan Plant Protection Association on October 18, 1975), pages 201 and 391, it is a known agricultural and horticultural fungicide. Carbendazine is also known as an agricultural and horticultural fungicide in Japanese Patent Publication No. 45-11319. The present inventors conducted various studies on the control properties of tolclofos-methyl for wheat snow rot, with the aim of developing an effective simultaneous control agent for wheat snow rot caused by the above four diseases. As a result, it was found that tolclofos-methyl has antibacterial activity against the above-mentioned large-grained sclerotia fungi, black-grained small-grained sclerotide fungi, and brown-grained small-grained sclerotide fungi, and also has control activity against wheat snow rot caused by these fungi. However, it has little effect on controlling red snow rot, which often causes damage in areas with heavy snowfall.
The practicality of using a single drug as a wheat snow rot control agent is low. In order to develop a practical agricultural and horticultural fungicide that takes advantage of the strengths of tolclofos-methyl and supplements its weaknesses, the present inventors tried mixing tolclofos-methyl with various chemicals and conducted various studies on the effects of the mixture. did. As a result, as mentioned above, it has been found that a novel fungicide prepared by mixing tolclofos-methyl with one of thiabendazole or carbendazine is an excellent fungicide that meets the above objectives. As is clear from the following test examples, the fungicide of the present invention has a control effect not only against wheat snow rot caused by any of the four plant pathogenic bacteria mentioned above, but also against rice blast and rice blast, which are important diseases of rice. It also exhibits an extremely high control effect against blight, and these effects are exerted with remarkable synergism that cannot be inferred from the use of each active ingredient alone. The present invention was made based on this new knowledge, and since the fungicide of the present invention can synergistically control the above-mentioned diseases, the amount of the active ingredient used is smaller than the usual amount used alone. Moreover, it is a labor-saving and economical pest control agent because it can control various diseases at the same time with one drug, and its practicality is high. To formulate the agricultural and horticultural fungicide of the present invention, the active ingredient and various carriers and various auxiliaries that are commonly used in the formulation of agricultural chemicals are added to form powders (including DL type powders), wettable powders, and liquids. , flowable, fine granules,
It can be used in any desired form such as granules or tablets. In the present invention, it is appropriate to mix the active ingredients in a weight ratio of 1 to 10 parts of thiabendazole or carbendazine to 1 part of tolclofos methyl, but the proportion may vary depending on the conditions at the time of application and the situation of disease occurrence. The ratio can be changed as appropriate. Furthermore, the agricultural and horticultural fungicide of the present invention may be used in combination with other fungicides, insecticides, herbicides, etc. Next, examples of the present invention will be shown. Example 1 (hydrating agent) 30 parts of tolclofos-methyl (parts by weight, the same applies hereinafter),
Thiabendazole 30 parts, white carbon 5 parts,
5 parts of alkylbenzene sulfonate and diatomaceous earth
Put 30 parts into a ribbon mixer, mix well, thoroughly crush with an atomizer, and mix again with the ribbon mixer to obtain a hydrating agent with a base ingredient content of 30% each. To control wheat snow rot with this wettable powder, dilute it 1,000 to 1,500 times with water, use an appropriate spraying device, and apply it at a rate of 100 to 150 per 10 ares before root snow and during snow melting. When sprayed on wheat during the growing season, various diseases caused by various snow rot fungi can be controlled individually or simultaneously. In addition, this hydrating agent can be added to 800 mL of water before or immediately after the outbreak of rice blast and rice sheath blight.
Dilute to ~1500 times and apply 10 times on rice plants using a suitable spraying device.
By spraying at a rate of 100 to 180 per area, these various diseases can be controlled singly or at the same time. Example 2 (Wettable powder) Torclofosmethyl 30 parts, carbendazine 30 parts
10 parts of white carbon, 5 parts of lauryl sulfate, 3 parts of sodium lignin sulfonate, and 22 parts of diatomaceous earth are mixed in the same manner as in Example 1 to obtain a wettable powder. The procedure for using this hydrating agent is the same as in Example 1. Example 3 (Powder) 3 parts of tolclofos-methyl, 2 parts of thiabendazole
1 part, 3 parts of white carbon, 0.5 parts of PAP (physical property improver), and 91.5 parts of diatomaceous earth are put into a ribbon mixer and mixed, and then thoroughly mixed with the ribbon mixer again to obtain a powder. This powder can be used to control various diseases caused by various snow rot fungi, either singly or simultaneously, by spraying it on wheat during the growing season before root snow or when the snow melts at a rate of 3 to 5 kg per 10 ares using an appropriate spraying device. In addition, this powder can be used to control rice blast and rice sheath blight individually or simultaneously if it is sprayed at a rate of 3 to 4 kg per 10 ares before or immediately after the outbreak of rice blast and rice sheath blight using an appropriate spraying device. Can be done. Example 4 (Powder) 3 parts of tolclofosmethyl, 2 parts of carbendazine
1 part, 3 parts of white carbon, 0.3 part of PAP (physical property improver) and 91.7 parts of diatomaceous earth are mixed and ground in the same manner as in Example 3 to obtain a powder. The procedure for using this powder is the same as in Example 3. Next, the effect of the agricultural and horticultural fungicide of the present invention on controlling crop diseases will be explained using test examples. Test example 1 Wheat snow rot control effect test In the field of a general farmer in Shiyubetsu, Shirataki Village, Monbetsu District, Hokkaido, 10.5 kg of N and P ₂ O ₅ of each component were added per 10 ares.
15 kg, and 10 kg of K ₂ O was applied and mixed in the entire layer. Then, on September 15th, 13 kg of autumn wheat (variety: Horosiriku wheat) seeds were sown per 10 ares by back-and-forth sowing in a furrow width of 30 cm. Each test plot was conducted using the randomized block method in three consecutive plots of 10 m ² each. The test chemicals were each wettable powder prepared according to Examples 1 and 2, diluted with water to a predetermined concentration, and then sprayed on November 15th using a small automatic sprayer at 120 doses per 10 ares. The disease onset investigation was conducted on April 25, after the snow melted, by determining the disease severity for each pathogen using the following disease investigation criteria, and then calculating the control value (%) of each test agent. Disease investigation criteria Index Severity of disease 0 Healthy 1 Less than half of the leaves are dead 2 More than half of the leaves are dead 3 Less than half of the stems are dead 4 More than half of the stems are dead Disease onset Degree = Σ (index × number of stocks by degree) / 4 × total number of research stocks ×
100 Control value (%) = (1-Severity of disease by each pathogen in the area where the chemical was sprayed/Intensity of the disease by each fungus in the area without spraying) x 100 The results are shown in Table 1.

【table】

[Table] Test Example 2 Rice blast disease field seedling control effect test Dried rice (cultivar Sasanishiki) was soaked and sterilized in a 200 times solution of Benlate T Wettable Dispersible 20 (commercially available seed disinfectant brand name) for 48 hours. Seed rice that had been immersed for germination using a conventional method was sown in rows in the field. Each test area is 1 area 1
It was performed as a trifecta of ^m2 . For chemical spraying, mix the wettable powder containing each single active ingredient with water to a final spray concentration of 2.
Add equal amounts of double solution and its chemical solution and spray 100 ml of each area three times with a small automatic sprayer (the first chemical spray was applied to rice seedlings at the 3.5 leaf stage, 2 days before inoculation with the disease, and the second spray was applied to rice seedlings at the 3.5 leaf stage,
The second chemical spraying was carried out 2 days after the inoculation, and the third chemical spraying was carried out 8 days after the second spraying). For inoculation, small pieces of rice blast diseased leaves prepared in advance were uniformly scattered over the entire surface of the test plot, and covered with plastic overnight to encourage the onset of rice blast disease. In the disease onset investigation, the ratio (%) of the dead area of rice blast lesions was investigated on the 15th day after the third chemical application, and the control value (%) was calculated using the following formula. Control value (%) = (1 - Average ratio of rice blast disease spot dead area in treated area/average ratio of rice blast lesion dead area in untreated area) x 100

【table】

【table】

[Table] Test Example 3 Rice sheath blight control effect test Seed rice (variety Koshihikari) whose seeds were sterilized in the same manner as Test Example 2 was raised in a box according to general practice.
The young petals were mechanically transplanted to Honda (at a cultivation density of 30 cm x 15 cm) on the 15th of May. Honda fertilizer amount is phosphorus reduction per 10 are.
30 kg of S550 (15-15-10), 10 kg of heavy calcined phosphorus, and 17 kg of NK chemical (17-0-17) as top dressing were applied on July 18th. The scale of the test was 15 m ² per section, using the randomized block method in triplicate. For chemical spraying, each test chemical prepared in the same manner as in Test Example 2 was applied during the panicle formation period (July 30th) and the heading period (August 30th).
On the 16th), using a backpack-type fully automatic sprayer, 150 particles were sprayed per 10 ares at a time. The disease onset survey was conducted on September 15th, and the disease severity was determined for 50 plants in each district using the following survey criteria for each disease index, and then the average control value (%) against rice sheath blight was calculated according to Test Example 2. Rice sheath blight disease onset investigation criteria Disease index 4: Plants in which the highest affected leaf sheath position in one plant reaches the flag leaf 3: Plants in which the highest affected leaf sheath position in one plant reaches the next leaf 2: Plants in one plant 1: A plant whose highest affected leaf sheath position has reached the 3rd leaf. 1: A plant whose highest affected leaf sheath position has reached the 4th leaf. 0: A plant whose highest affected leaf sheath position has reached the 5th leaf. Strains affected by disease severity = Σ (each disease index × number of applicable strains) / 4 × number of investigated strains × 100 The results are shown in Table 3.

[Table] Shows the severity of the disease.

Claims (1)

[Claims] 1 0,0-dimethyl0-2,6-dichloro-4
-methyl phenyl phosphorothioate and 2-(4
- Thiazolyl) benzimidazole or a mixture of the two with methyl-2-benzimidazole carbamate as an active ingredient.