JPS6340763B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an agricultural and horticultural fungicide characterized by containing kasugamycin or its salts and methyl 1-(n-butylcarbamoyl)benzimidazol-2-yl-carbamade (hereinafter referred to as benomyl) as active ingredients. Kasugamycin is an antibiotic produced by an actinomycete named Streptomyces kasugaensis, and has a specific therapeutic effect against rice blast fungus (Japanese Patent Publication No. 6818/1973 and Japanese Patent Publication No. 41/1989).
21757), has extremely low toxicity to human stock, fish and shellfish, and has no chemical toxicity to rice, making it widely used as a safe rice blast control agent. However, kasugamycin has a drawback of lacking residual efficacy against rice blast. The present inventors have developed a number of chemical compounds in order to develop a practical fungicide that can take advantage of the advantages of kasugamycin or its salts, which are currently used as a representative example of safe agricultural chemicals, and compensate for the drawbacks mentioned above. I tried it. As a result, by combining kasugamycin or its salts with benomyl (Japanese Patent Publication No. 23274/1974), which has been put into practical use as a fungicide for fruit trees, vegetable horticulture, and seed disinfection, it is possible to use it as a fungicide. It has been found that the above objectives can be fully achieved. The agricultural and horticultural fungicide of the present invention not only has a spraying effect against rice blast, but also has a water surface application effect on rice cultivated in seedling boxes for mechanical transplantation of young seedlings, which has recently become widespread, and on rice after transplanting to Honda. Fully usable. It can also be used as a control agent for beet brown spot and tomato leaf mold. Moreover, the control effect is more synergistic when used as a fungicide consisting of kasugamycin or its salts mixed with besomyl than when kasugamycin or its salts are applied as a single agent, and the effect is long-lasting. Has residual effect. The appropriate blending ratio of the active ingredients in the agricultural and horticultural fungicide of the present invention is to mix 1 part of kasugamycin or its salts with 10 to 100 parts of benomyl by weight. The blending ratio can be changed as appropriate depending on the occurrence situation. When formulating the agricultural and horticultural fungicide of the present invention,
By adding various carriers and auxiliary agents used in conventional methods, it can be made into desired forms such as powders, wettable powders, emulsions, granules, and tablets. Next, examples of the present invention will be shown. Example 1 (Wettable powder) 1 part of kasugamycin hydrochloride (parts by weight: the same below), 20 parts of benomyl, 27 parts of diatomaceous earth, 50 parts of clay, and 2 parts of Solpol 8048 (trade name of an emulsifier manufactured by Toho Chemical Industry Co., Ltd.) The mixture was uniformly mixed and ground to prepare a wettable powder. This hydrating powder can control rice blast if it is diluted 500 to 1000 times with water and sprayed on rice bodies at a rate of 100 to 150 per 10 ares before or immediately after the outbreak of rice blast. can. In addition, for rice grown in seedling boxes, this drug should be applied the day before transplanting to Honda.
If you irrigate 500x at a rate of 200 to 500ml per box,
It is possible to perform initial control against rice blast after transplantation. In addition, rice seed blight and rice blight can be controlled by sterilizing rice seeds by soaking them in a 100 times solution of this agent for 24 hours. Example 2 (Powder) Kasugamycin hydrochloride 0.1 part, Benomyl 20 parts,
74.9 parts of talc and 5.0 parts of white carbon are uniformly mixed and pulverized to make a powder, and using an appropriate scattering device, it is directly spread on rice plants at 1.5 to 4 kg per 10 ares.
Rice blast can be controlled by dusting at a ratio of . Example 3 (Granules) Kasugamycin hydrochloride 0.5 parts, Benomyl 5 parts,
After weighing 3 parts of sodium lignin sulfonate, 2 parts of sodium lauryl sulfate, and 89.5 parts of clay, water was added and the mixture was thoroughly kneaded, granulated, dried, and sieved to obtain 64 to 32 mesh granules. In order to control rice blast in the early stages after transplanting to Honda, apply this agent directly to rice grown in seedling boxes at a rate of 30g per box on the day before transplanting to Honda (at the 2.5 leaf stage of rice seedlings). do it. In addition, for Honda's leaf blast and ear blast, use this granule at 10%.
If applied to the water surface at a rate of 1.5 to 4 kg per area,
These rice blast diseases can be controlled. Next, the disease control effect of the agricultural and horticultural fungicide of the present invention will be explained using test examples. Test Example 1 (Rice blast control effect test: Field seedling) Dry rice (variety: Sasanishiki) was treated with a 200 times solution of Benlate T wettable powder 20 (commercially available seed disinfectant).
After being sterilized by soaking for a period of time, the paddy was soaked in a conventional manner and subjected to germination treatment.The paddy was then sown in rows in the field (June 5 day), when the third leaf unfolds,
Strips of diseased leaves prepared in advance were uniformly scattered over the entire surface of the test plot (June 30th) and covered with vinyl overnight to encourage disease onset. The diseased leaves used as inoculum sources were two strains of kasugamycin-susceptible and kasugamycin-resistant bacteria, isolated from rice blast disease affected panicles collected in 1971 from a paddy field in the Shonai region of Yamagata Prefecture, and incubated for 10 min each on an oatmeal agar medium. After culturing for 1 day, the aerial mycelium was removed by washing with water, and the spores of susceptible bacteria and resistant bacteria obtained by culturing for 2 days under a fluorescent light were collected.
It was obtained by suspending it in water at a ratio of 4:4 and inoculating it into rice seedlings (rice seedlings sown thickly in plant butts in a greenhouse). The chemical spraying was performed by spraying a predetermined concentration chemical solution of the test wettable powder prepared according to Example ¹ per 1 m2 of 1 area.
The mixture was sprayed three times using a small automatic sprayer to a volume of 100 ml (sprayed three times 1 day, 4 days, and 6 days after inoculation with the pathogen). The disease outbreak survey was conducted 15 days after the third chemical spraying, and the proportion of the area of the rotten lesions (%) was determined in accordance with the outbreak prediction survey standards (“Guidelines for Implementation of Pest Outbreak Prediction Project”, 1952, edited by the Agricultural Improvement Bureau, Ministry of Agriculture and Forestry). The control value (%) was determined using the following formula. This test was conducted in two consecutive sessions in one area, and the average control value (%)
was calculated. Control value (%) = (1 - ratio of dead area of blast lesions in sprayed area / ratio of dead area of blast lesions in non-sprayed area) x 100 In addition, in the present invention, by mixing two types of chemicals, synergy can be achieved. The expected value (PE) of the mixture was calculated using the following formula, and the presence or absence of a synergistic effect was determined from the relationship with the actual value (PC). PE (%)=Pa+Pb(100-Pa)/100 In this formula, Pa indicates the control value on the fruit side due to the use of kasugamycin, and Pb indicates the control value on the fruit side due to the use of benomyl. Judgment is based on the following criteria. PC>PE: Synergistic effect PC=PE: Additive effect PC<PE: Antagonistic effect The results are shown in Table 1.

[Table] Test Example 2 (Rice blast control effect test: Application of seedling boxes) For the test rice, seed rice (variety: Sasanishiki) was sterilized in the same manner as in Test Example 1, and after germination, seedlings were grown in boxes according to the usual method. (Seed amount: dry matter 200g/box),
At the 2.5 leaf stage, 30 g of granules prepared according to Example 3 were dispersed per box. After applying this granule to raise seedlings, water was applied to approximately 200 ml per box, and one day after application, six plants were planted (transplant spacing: 10 cm) and transplanted to Honda (June 10). The blast control effect on transplanted rice seedlings was evaluated twice, 10 days after transplantation and 18 days after transplantation.
The rice blast fungus spore suspension obtained according to Test Example 1 was inoculated by spraying, and each test plot was immediately covered with vinyl to promote the onset of the disease. In the disease onset investigation, 11 days after the second infestation, the ratio (%) of rice blast disease spot dead area was investigated on the top three leaves of each leaf, and the control value (%) was calculated using the following formula. The test was conducted in duplicate with 30 plants per area, and the average control value (%) was calculated.
The results are shown in Table 2. Control value (%) = (1 - percentage of area of rice blast disease and withered lesions in treated area / percentage of area of rice blast disease and withered area of non-treated area) x 100

[Table] Test Example 3 (Tomato leaf mold control effect test: open field) Tomatoes (variety: Beiju) were sown, and 30 days later, they were planted according to a conventional method (planting in 2 rows with a spacing of 45 cm).
Chemical spraying was carried out on June 20, at the time of the first appearance of tomato leaf mold.
On Sunday, June 25th, and July 1st, a predetermined concentration chemical solution of the sample hydrating powder prepared according to Example 1 was applied at 200 ml per 10 ares using a shoulder-type semi-automatic sprayer.
(However, for the third application, the number was 250). To investigate the onset of the disease, 10 days after the third spraying, three plants were arbitrarily selected from three locations in each district, and the ratio (%) of the tomato leaf mold disease onset area was investigated on each equidistant leaf on the node.
The control value (%) was calculated from the following formula. The test was conducted in duplicate with 10 plants per area, and the average control value (%) was calculated. The results are shown in Table 3. Control value (%) = (1 - ratio of area affected by tomato leaf mold in treated area / ratio of area affected by tomato leaf mold in non-treated area) x 100

【table】

[Table] Test Example 4 (Rice blast test: Pot) Using third-leaf stage seedlings of paddy rice (variety: Asahi) cultivated in clay pots with a diameter of 9 cm in a greenhouse, kasugamycin-susceptible blast fungus and kasugamycin-resistant blast fungus were tested. The effect on pathogens was investigated. A diluted solution of each drug at a predetermined concentration was sprayed onto the above rice seedlings using a spray gun at a volume of 20 ml per three pots. The next day, a spore suspension of rice blast fungus (Pyri-cularia oryzae) cultured in advance on an oatmilk agar medium was spray inoculated. After inoculation, the plants were kept in a humid room at 24°C for 5 days to investigate the later onset of disease. The investigation into the onset of the disease is the third step.
The number of lesions per leaf was examined, and the control value (%) was calculated using the following formula. Control value (%) = (1 - number of lesions in sprayed area/number of lesions in non-sprayed area) x 100 The results are shown in Table 4.

【table】

Claims (1)

[Claims] 1 Kasugamycin or its salts and methyl 1-
An agricultural and horticultural fungicide characterized by containing (n-butylcarbamoyl)benzimidazol-2-ylcarbamade as an active ingredient.