JPH0228562B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a labor-saving and effective method for controlling diseases that occur in rice seedlings after being transplanted to seedling boxes and rice fields by simply applying a small amount of chemicals to the seedling box when rice seeds are sown into the seedling box. and a method for promoting the growth of rice after transplanting to Honda. Specifically, the active ingredients are kasugamycin or its salts (hereinafter referred to as KSM) and 3-allyloxy-1,2-benziisothiazole-1,1.
- Add a granular or powdered agent containing a mixture with carbon dioxide (hereinafter referred to as probenazole) to a rice seedling box (length x width x height: 30cm x 60cm x
50mg of KSM as the active ingredient amount per 3cm)
or 2000mg, Probenazole 100mg or more
The present invention provides a labor-saving method for controlling rice diseases and a method for promoting rice growth by treatment at the time of sowing, characterized in that the method is applied at a rate of 1000 mg. The drug granules or powders may be applied to the seedling nursery box by any suitable method. From a practical standpoint, the following three methods can be cited. 1) Method of mixing with soil for covering soil in advance and covering with soil after sowing (method of mixing soil for covering soil) 2) Method of mixing with soil for raising seedlings (cultivating soil for bed soil and cultivation soil for covering soil) before sowing and covering with soil after sowing ( 3) Spraying after sowing and then covering with soil (pre-treatment method for covering with soil after sowing). According to the method of the present invention, rice seedling rot and rice seedling blast that occur during the seedling raising period can be prevented without causing chemical damage to rice, and rice seedlings can be transplanted into rice fields.
In addition to controlling rice leaf blast, which occurs after about 30 days, it also promotes rooting (promotes elongation of tap root length and increase in number of roots) and growth elongation (increases plant height) of rice seedlings after transplanting to Honda. ), etc., were found to be able to significantly promote the growth of rice seedlings. Conventionally, there is a known method for simultaneously controlling rice blast and rice seedling rot by treating seedling boxes with a granular agent containing KSM (see JP-A-56-75417 to JP-A-56-75420). ). There is also a known method for controlling rice blast that occurs in Honda by applying granules containing probenazole to seedling boxes from 3 days before transplanting to Honda to the day of transplanting. Furthermore, there is a known method for controlling rice blast disease by spraying powder or wettable powder containing a mixture of KSM and probenazole on rice (Japanese Patent Publication No. 18155/1973), but this method significantly reduces the growth of rice. It is not known how to promote this. In the present invention, known KSM and probenazole are mixed in a specific ratio as described above, and a granular or powdered agent containing the same is treated in a specific usage method, thereby improving seedling raising as described above. In addition to being able to control rice blast disease that occurs after transplanting to Honda for a long period of time,
Completely new knowledge is provided that KSM, probenazole, and a mixture of KSM and probenazole significantly promote rice growth, which could not be found with any of the techniques. In recent years, rice seedlings for mechanical transplantation of young seedlings, which have become popular nationwide, are sown densely and kept at a constant temperature of 28 to 35 degrees Celsius for two to three days to ensure uniform germination, and then heated to a high temperature. It is often cultivated under humid conditions. For this reason, rice seedling rot disease caused by rice blast disease (Pseudomonas glumae) occurs frequently and is becoming a problem. Until now, in order to control rice blast among these diseases in nursery box cultivation, grains containing isoprothiolane (chemical name: diisopropyl-1,3-dithiolane-2-ylidenemalonate) as an active ingredient have been used. A method in which 50 to 75 g (12% granules; 6,000 to 9,000 mg of active ingredient) is applied per box to seedling boxes several days after sowing to just before transplanting, and granules containing probenazole are applied to seedling boxes from 3 days before to immediately before transplanting. 20-30g per box (8%
Granules: 1,600mg to 2,400mg of the active ingredient) have been put into practical use. According to this method,
Although rice blast can be practically controlled at the usual application rate of each granule, it has no control effect at all on rice seedling rot. In addition, if these chemicals are applied in larger amounts than the usual usage, or if the usual usage is mixed with the seedling cultivation soil before and after sowing, or treated before covering with soil after sowing, as in the present invention, rice seedlings Not only is it not possible to increase the control effect against rot, but it only gives the undesirable result of stunting and suppressing the growth of rice. Therefore, there is a need to establish chemicals and control techniques that can practically control not only rice blast but also rice seedling rot in seedling box cultivation. The present inventors have conducted extensive research to develop a new pest control agent applied to seedling boxes and its pest control technology that meets these demands. As a result, we first applied KSM in the form of granules to a rice seedling box (length x width x height: 30 cm).
x 60cm x 3cm: An average of 16 to 18 boxes of young seedlings are used per 10 acres of Honda.
By applying 2,000 mg of rice blast using either the soil-covering soil mixing method, the full-layer mixing method, or the post-seeding and pre-covering method, the rice blast disease will not be harmed at all and will not be controlled by conventional drugs. It was discovered that it was possible to simultaneously control rice seedling rot, which had been difficult. Especially for rice blast, 1000mg
Treatments below 1000 are effective against seedling blast;
It was discovered that when the concentration exceeds mg, it has an excellent effect on leaf blast that occurs after transplanting to Honda, and established a technology for simultaneous control of rice seedling rot and rice blast (Special Application No. 117025-1983, No. 55 -No. 117026,
55-117027). However, these methods
The duration of the leaf blast control effect after transplanting is
Even if 1000 mg or more of KSM is treated, it has the disadvantage that it is limited to the 3rd to 4th leaf stage of rice, which is about 10 days after transplantation. In order to overcome these drawbacks of KSM, the present inventors combined KSM with various drugs.
The present invention was achieved through intensive research on the control effects of rice seedling rot and rice blast.
That is, according to the present invention, by applying the above-described method to a seedling raising box, rice seedling rot and rice seedling blast that occur during the seedling raising period, and until about 30 days after transplanting the rice seedlings to Honda, can be prevented. In addition to controlling rice blast disease that occurs during this period, it can also significantly promote the growth of rice seedlings after transplanting to Honda. In contrast to the present invention, the conventional method of using probenazole granules as described above is not effective against rice seedling rot and rice seedling blast that occur during the early stage of seedling raising. In addition, if the same method of use as in the present invention is applied in the range of 1600 mg to 2400 mg, which is the usual amount used, although it shows control activity against rice seedling rot, it is not practical, and furthermore, it is not practical for rice seedling rot. This method cannot be used to significantly suppress Furthermore, even if the drug dose is reduced to 1000 mg or less, rice growth will still be suppressed within the range of 500 to 1000 mg, and if the drug dose is reduced to 500 mg or less,
Although it does not suppress the growth of rice, it is completely ineffective against rice seedling rot, and the control effect against rice seedling blast disease is also poor, making this method impractical. However, surprisingly, when 100 mg to 1000 mg of such probenazole and 50 mg to 2000 mg of KSM are used in combination, it has the effect of significantly promoting rice growth rather than suppressing it. I found out. in this case,
Probenazole has a significant growth promoting effect in the range of 100 to 500 mg. In addition, as a disease control effect, it synergistically exerts a control effect on rice seedling rot and rice seedling blast in seedling boxes, and the purpose of control can be fully achieved with a low dose of treatment. In addition, for leaf blast disease after transplanting to Honda, even if KSM and probenazole are mixed at a dose that does not show any residual effect when used as a single agent, the control is sufficient for practical use until about 30 days after transplantation. Effects can be obtained. The findings of the present invention are based on conventional rice blast control technology that involves spraying KSM-containing powders, wettable powders, emulsions, and liquids on Honda's rice stems and leaves, or applying granules alone to rice seedling boxes. , rice blast control technology by treating seedling boxes with a powder containing probenazole or isoprothiolane, or by spraying powders, wettable powders, emulsions, etc. containing a mixture of KSM and probenazole on Honda rice stems and leaves. This was something that no one could have predicted based on rice blast control technology, and was discovered for the first time by the present inventors. Therefore, the present invention not only provides a new application technology for KSM and probenazole, but also provides a completely new technology as a treatment agent for seedling boxes. In order to efficiently utilize the excellent effects of the present invention, it is necessary to simply process a granular or powdered agent containing KSM and probenazole in the ratios described above using the specific processing method described above. Otherwise, just follow the previous method of raising and cultivating seedlings. In this case, the term granular or pulverulent does not mean geometric granular or pulverulent, but the granular or pulverulent meaning commonly used in the field of agrochemical formulation technology. Therefore, as granules, granules, fine granules, fine granules F, and powders can be used, and as powders, powders, driftless (DL) powders, wettable powders, and coarse powders can be used. can. Below are examples of the production of granules and powders used in the present invention and examples of the method of the present invention.
The present invention is not limited only to these examples. In addition, parts in the production examples indicate parts by weight.
KSM also used hydrochloride. Production Example 1 Granules 1.15 parts of KSM, 0.15 parts of probenazole, 3 parts of calcium lignosulfonate and 95.7 parts of a talc-clay mixture were thoroughly kneaded and granulated, dried and sized to obtain granules. Production Example 2 Powder A powder was obtained by uniformly mixing 5.75 parts of KSM, 0.75 parts of probenazole, 0.5 parts of silicic anhydride fine powder, 0.5 parts of calcium stearate, and 92.5 parts of clay. Example 1 (Efficacy test for controlling rice seedling rot and seedling blast disease caused by rice bacterium) 1 Chemical treatment method (a) Mixing of culture soil for covering soil Commercially available granular culture soil (Kureha granule culture soil) was added to each seedling box. Filled with 1.8Kg as a bed soil,
The water from Step 2 was irrigated with fresh dew, and the rice seeds that had germinated and become pigeon-breasted were sown at an amount of 200 g (calculated as dry weight) per seedling raising box. Next, a certain amount of the granules prepared according to Production Example 1 and 0.6 kg of soil-covering soil were thoroughly mixed, and the seedling-raising box after sowing was covered with soil. (b) Sprinkling of grains after sowing and before covering with soil Fill a seedling box with commercially available granular culture soil to the capacity of 1.8 kg per box, and water with water from Step 2 using dew to germinate the seed rice, which has become pigeon-breasted. The seeds were sown in an amount of 200 g in terms of dry weight per seedling box. Then, a certain amount of the granules prepared according to Production Example 1 were dispersed and covered with 0.6 kg of culture soil for covering soil prepared in advance. (c) Mixing treatment of growing soil (full layer mixing treatment) A certain amount of granules prepared according to Production Example 1 and 2.4 kg of commercially available granular soil (Kureha granular soil) were thoroughly mixed, and 1.8 kg of the mixture was added to the bed soil. (The remaining 0.6 kg was used for covering soil.) Next, each seedling box was irrigated with water using dew, and 200 g of dry weight per seedling box was sown with germinated and pigeon-breasted rice seeds. Thereafter, the seeds were kept in a thermostat at 32°C for 2 days for germination, and after germination, they were cultivated in a plastic greenhouse. 2. Method for measuring control effectiveness (a) To investigate the onset of rice seedling rot, 10 days after sowing, examine the number of rotten and dead seedlings and the number of leaf sheath browning seedlings in one-fifth of the seedling boxes, and calculate the severity of the disease using the following formula. The rice seedling rot control value (%) was calculated from the comparison with the disease severity in the untreated area. Disease severity = Number of rotten and dead seedlings x 10 + Number of browned leaf sheaths x 3 / Total number of surveyed seedlings x 10
×100 (b) Regarding the effect of controlling seedling blast disease, 15 days after sowing, 15 ml of rice blast fungus spore suspension (spore concentration: 150 spores per field of view under a 150x optical microscope) was sprayed into each seedling box. in a humid chamber at ℃
It kept for 20 hours. After inoculation, they were transferred to the plastic greenhouse again, and 6 days after inoculation, the number of blast-spreading lesions on the second leaves of 300 seedlings per nursery box was investigated, and the blast control value (%) was calculated using the following formula. ) was calculated. Control value = (1-A/B) x 100 However, A indicates the total number of blast-spreading lesions on the 300 leaves surveyed (second leaves) in the treated plot, and B indicates the total number of blast disease expanding lesions on the surveyed 300 leaves (second leaf) in the non-treated plot. Second
Shows the total number of blast-spreading lesions on leaves). (c) The effect of controlling leaf blast after transplantation was investigated as follows. Pour 3.2 kg of air-dried paddy soil into Wadaner pots and add 3 g of ammonium sulfate per pot.
Fertilize with 3.6 g of lime superphosphate and 1 g of potassium chloride, add water, and stir thoroughly to form a paddy field. Then, 5 to 7 rice seedlings that had reached the 2.3 to 2.5 leaf stage 20 days after sowing were hand-planted, 3 plants per pot, with seedling growing soil still in place. 5 days, 10 days, 20 days, and 30 days after transplantation, a rice blast fungus spore suspension (approximately 150 spores per field under a 150x optical microscope) was added to each pot for each time. 3ml
were inoculated by spraying. After inoculation, the temperature is 24℃,
The plants were transferred to a controlled greenhouse with a relative humidity of 85 to 95%, and 6 days after inoculation, the number of blast-spreading lesions on the uppermost developed leaves at the time of inoculation was investigated, and the blast control value (%) was calculated using the following formula. Control value = (1-C/D) x 100, where C indicates the average number of blast-spreading lesions on one leaf examined in the treated area (the top expanded leaf at the time of inoculation), and D represents the number of lesions on one leaf examined in the untreated area. The average number of blast disease expansion lesions on (the uppermost expanded leaf at the time of inoculation) is shown. In addition, the diseased rice used in the rice seedling rot control effect test in this example was treated with a suspension of rice blight bacteria (bacterial concentration 10 ⁸
variety "Sasanishiki" obtained by spray inoculation of
It is the seed rice of In addition, the seed rice used in the rice blast control effect test in this example was the variety "Asahi" produced in Okayama Prefecture.
The test was conducted in three consecutive trials in one area, and the average control value was calculated. The results are shown in Tables 1 to 6.

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[Table] Example 2 (Rice growth promotion effect test) A certain amount of the granules prepared according to Production Example 1 were mixed with soil for covering soil in the same manner as in Example 1, sprinkled after sowing before covering, and mixed with soil for raising seedlings. The seeds were treated (full layer mixing treatment) and packed in seedling boxes, and then kept in a constant temperature chamber at 32℃ for 2 days for germination treatment.
The plants were greened in a greenhouse at 18 to 20°C, and 7 days before transplanting, normal cultivation management was carried out in a vinyl greenhouse to harden them and transplanted to a paddy field. On the day of transplantation and 14 days after transplantation, the growth status of the rice plants and leaf blight, which is a symptom of chemical damage caused by probenazole, were investigated. The seed rice used in the rice growth promoting effect test in this example was the variety Sasanishiki produced in Miyagi Prefecture. This test was conducted in three consecutive trials in each section, and the average value was calculated. In addition, the degree of leaf blight in rice was investigated using the following criteria. Large: Leaf withering occurs on 60% or more of the affected leaf area (second or third leaf) Medium: Leaves appear on more than 30% to less than 60% of the affected leaf area (second or third leaf) Small: Those with leaf withering occur on more than 1% to less than 30% of the relevant leaf area (second or third leaf) None: Those with no leaf withering The result is 7th As shown in Tables 1 to 12.

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[Table] Control agent test example (1) Test method KSM-probenazole powder corresponding to the composition of the powder composition described in Example 3 of Japanese Patent Publication No. 46-18155, namely 3-allyloxy-1,2-benzoiso A powder prepared by mixing 4 g of thiazole-1,1-dioxide, 0.5 g of kasugamycin, and 95.5 g of talc was applied to rice seedlings at the 5th true leaf stage at a rate equivalent to 3 kg per 10 ares according to the experimental example in the above publication. The presence or absence of growth promoting effect on rice was tested by spraying. The growth survey was conducted 4 days after the chemical spraying, and the numbers shown in the column for number of stems per plant and plant height are the number of stems (17.6 plants/plant) and plant height (53.4 cm) in the untreated area under the same conditions. It is a relative value when is set to 100. (2) Test results The results are shown in the table below.

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Claims (1)

[Claims] 1. When rice seeds are sown in seedling boxes, kasugamycin or its salts as active ingredients and 3-
Allyloxy-1,2-benziisothiazole-
Add a granular or powdered agent containing 1,1-dioxide to a seedling box (length x width x height; 30cm).
The former is 50 as the amount of active ingredient per cm x 60 cm x 3 cm)
A labor-saving method for controlling rice diseases and a method for promoting rice growth by treatment at the time of sowing, characterized in that the latter is applied at a rate of 100 mg to 1000 mg. 2. The method according to claim 1, wherein the granular or powdered agent is mixed in advance with the soil for covering the seedling box and applied by covering the seedlings with soil after sowing. 3. The method according to claim 1, wherein the granular agent or powder agent is applied by mixing the granular agent or powder agent with the soil for the bed of the seedling box and the soil for covering the seedlings in advance. 4. The method according to claim 1, wherein the granular agent or powder agent is applied by spraying the rice seeds after sowing them in seedling boxes and before covering with soil.