JPS6124362B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a beet brown spot control agent characterized by containing diisopropyl 1,3-dithiolane-2-ylidenemalonate (hereinafter referred to as isoprothiolane) as an active ingredient. Beet brown spot is a disease that has been known for a long time and is caused by the beet brown spot fungus (Cercospora beticola), but it is still a concern as a common disease. Damage caused by the beet brown spot fungus causes brown circular lesions on the leaf blades, and the leaves in large numbers turn brown, dry, shrink, and die. When most of the adult leaves die,
Since the plant continues to grow by regenerating new leaves from the center of the root neck, this disease not only reduces root weight but also reduces sugar content. Traditionally, TPTH has been used as a control agent for beet brown spot disease.
(generic name), benomyl (generic name), and thiophanate methyl (generic name), but due to the emergence of drug-resistant bacteria to benomyl, cross-resistance to benomyl-resistant bacteria occurred with benomyl and drugs of the same family. The medicinal efficacy of methyl thiophanate and carventazole (generic name) has decreased, and as a result, the use of these drugs has been restricted, and currently only TPTH is used at concentrations of 200 to 300 ppm. . Recently, TPN (generic name) has also been used, but its concentration is 1000
It is not practical due to its high concentration of 1500 ppm. Therefore, it is desired to develop a drug that exhibits a high control effect against this disease, especially against drug-resistant bacteria such as benomyl. As a result of repeated research to solve this problem, the present inventors have found that isoprothiolane, which is highly effective against rice blast, is surprisingly effective against benomyl-resistant bacteria of beet brown spot at low concentrations. The present invention has been completed based on the discovery that it exhibits a high pesticidal effect. Furthermore, by using the isoprothiolane in combination with a conventionally used drug, it is possible to simultaneously control drug-resistant and susceptible bacteria of beet brown spot at a low dose. Isoprothiolane used in the present invention has a melting point of 51
It is a known compound that exhibits physical properties at ~52°C and is used as a rice blast agent, in which case the concentration used as a foliage treatment agent is 400 ppm. According to the present invention, isoprothiolane is more effective against beet brown spot disease caused by benomyl drug-resistant bacteria than benomyl drug-susceptible bacteria, and in pot tests, it was shown that isoprothiolane is more effective against beet brown spot disease caused by benomyl drug-resistant bacteria than at 100 ppm. Effective, but in actual use
It is fully effective in the range of 1000ppm. These things are completely unexpected based on conventional knowledge. In addition, drugs that can be used in combination with isoprothiolane include benomyl (generic name): methyl 1-(butylcarbamoyl)benzimidazol-2-ylcarbamate; thiophanate methyl (generic name): 1,2- Di-(3-methoxycarbonyl-2-thioureido)benzene; Carbendazole (generic name): Methylbenzimidazolo-
2-yl carbamate; TPTH (generic name): triphenyltin hydroxide; TPN (generic name): tetrachloroisophthalonitrile; maneb (generic name): Manganese ethylene bisdithiocarbamate; mancozeb (generic name): zinc ion Coordination Manganese ethylene bisdithiocarbamate; oxine copper (common name): 8-hydroxyquinoline copper; polyoxine (common name): polyoxine complex B, and the like. The pesticidal agent according to the present invention may be formulated in the same manner as ordinary agricultural chemicals, and examples of carriers include solid carriers such as talc, clay, kaolin, bentonite, diatomaceous earth, and white carbon; alcohol, dioxane, acetone, and cyclohexane. ,
Liquid carriers such as methylnaphthalene, DMF and DMSO; surfactants include alkyl sulfate esters, alkyl sulfonates, polyoxyethylene alkylaryl ethers, polyethylene sorbitan monoalkylate, carboxymethyl cellulose and Arabic gum; By appropriately blending additives with auxiliaries, granules,
It may be formulated into dosage forms such as wettable powders, powders, DL formulations, microgranules, emulsions, floor pull suspensions, etc., and used as is or after dilution. Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to the scope described in the Examples, and the compounding ratio and the types of carriers, surfactants, and auxiliary agents can be changed. (In the examples, parts indicate parts by weight) Example 1 Isoprothiolane 40 parts Diatomaceous earth/clay mixture 55 parts Polyoxyethylene nonyl phenyl ether 5 parts The above ingredients were uniformly mixed and pulverized to prepare a wettable powder. Example 2 Isoprothiolane 40 parts Tetrahydrofuran 20 parts Xylene 25 parts Mixture of polyoxyethylene nonylphenyl ether and alkylbenzene sulfonate 15 parts The above ingredients were uniformly mixed and dissolved to form an emulsion. Example 3 Isoprothiolane 4 parts Diatomaceous earth/clay/talc mixture 95 parts Calcium stearate 1 part The above ingredients were uniformly mixed and pulverized to form a powder. Example 4 Isoprothiolane 40 parts Benomyl 10 parts Polyoxyethylene nonyl phenyl ether 5 parts Diatomaceous earth/clay mixture Remaining part The above ingredients were mixed and pulverized uniformly to obtain a wettable powder. Example 5 Isoprothiolane 40 parts Methyl thiophanate 20 parts Polyoxyethylene nonyl phenyl ether 5 parts Diatomaceous earth/clay mixture Remainder The above ingredients were uniformly mixed and pulverized to obtain a wettable powder. Example 6 Isoprothiolane 40 parts Carbendazole 10 parts Polyoxyethylene nonyl phenyl ether 5 parts Diatomaceous earth/clay mixture Remaining part The above ingredients were uniformly mixed and ground to obtain a wettable powder. Example 7 Isoprothiolane 40 parts TPTH 7 parts Polyoxyethylene nonyl phenyl ether 5 parts Diatomaceous earth/clay mixture Remaining part The above ingredients were uniformly mixed and pulverized to obtain a wettable powder. Example 8 Isoprothiolane 30 parts TPN 30 parts Polyoxyethylene nonyl phenyl ether 5 parts Diatomaceous earth/clay mixture Remaining part The above ingredients were uniformly mixed and pulverized to obtain a wettable powder. Next, in order to prove the effectiveness of the drug of the present invention,
Some test examples are shown below. Test Example 1 Effect on beet brown spot disease Agar plates were prepared by containing the drug of the present invention at a predetermined concentration in a potato agar medium, and the pre-cultured beet brown spot bacteria were transplanted onto the plates and cultured at 25°C. The growth inhibitory effect was evaluated after 10 days. The bacterial growth inhibitory effect was evaluated by measuring the diameter of the bacterial flora and calculating it using the following formula. Growth inhibition rate (%) = A-B/A x 100 A: Diameter of bacterial flora in untreated area (mm) B: Diameter of bacterial flora in treated area (mm) The results are shown in Table 1 for easy understanding. Therefore, we adopted the following four-level standard scale. 4... 100% growth inhibition 3... Growth inhibition of 75% or more but less than 100% 2... Growth inhibition of 50% or more and less than 75% 1... Less than 50% growth inhibition A control test was also conducted, and the results are also listed.

[Table] *Benomyl-based drug-infected bacteria and resistant bacteria are
This is a strain obtained from beets in a garden.
Test Example 2 Preventive effect against beet brown spot disease A medicinal solution of the agent of the present invention prepared at a predetermined concentration was sufficiently sprayed on beets (cultivar Monohill) with 5 to 6 developed leaves. One day after the spraying, a spore suspension of brown spot fungus was sprayed and left in a humid room overnight. 20 days after inoculation, the lesion area ratio was investigated and the control value was calculated using the method below. Control value (%) = AB/A x 100 A: Percentage of lesion area in untreated area B: Percentage of lesion area in treated area The results are shown in Table 2. In addition, a control test was conducted and the results are also listed.

[Table] Test Example 3 Therapeutic effect on beet brown spot A spore suspension of the brown spot fungus was sprayed on beets (cultivar Monohill) with 5 to 6 developed leaves, and after being left in a humid room overnight, A chemical solution of the drug of the present invention adjusted to a predetermined concentration was sufficiently sprayed. Twenty days after inoculation, the lesion area ratio was investigated, and the control value was calculated in the same manner as in Test Example 2. The results are shown in Table 3. In addition, a control test was conducted and the results are also listed.

[Table] Test Example 4 Controlling effect of the mixture on benomyl-based drug-resistant bacteria The isoprothiolane and benomyl mixture was diluted to a predetermined dose and tested in the same manner as in Test Example 2. The results are shown in Table 4. In addition, a control test was conducted and the results are also listed.

【table】

[Table] As can be seen from the above results, the mixture of isoprothiolane and benomyl showed an extremely high pesticidal effect at a low dose.

Claims (1)

[Claims] 1 diisopropyl 1,3-dithiolane-2-
A beet brown spot control agent characterized by containing ylidene malonate as an active ingredient.