JPH04173703A - Labor-saving control of rice disease injury - Google Patents

Abstract

PURPOSE:To accomplish the title effective, labor-saving control of both seed- infective and seedling damping-off disease injuries simultaneously by applying a dilute solution of a benzimidazole-based chemical agent or its mixture with thiuram or captan on the rice seeds immediately after seeding on raising seedling boxes. CONSTITUTION:A dilute solution of (A) a benzimidazole-based chemical agent or of its mixture with (B) bis(dimethylthiocarbamoyl)disulfide(thiuram) or N- trichloromethyl thiotetrahydrophthalimide(captan) is applied on the rice seeds immediately after seeding on raising seedling boxes as dosages of A=5-5000 (pref. 40-1000)mg and B=5-3000 (pref. 60-600)mg per box (60cmX30cmX3cm), thus accomplishing the objective control in a labor saving way of both seed- infective and seedling damping-off disease injuries simultaneously in a simple operation and with no concern for the need of waste liquor treatment or environmental pollution if compared to conventional seed sterilization techniques.

Description

[Detailed Description of the Invention] l) Purpose of the Invention Industrial Field of Application The present invention enables seed disinfection, which is essential for raising rice seedlings in rice seedling boxes, without performing operations such as soaking, powder coating, and spraying. The present invention relates to a disease control method for simultaneously controlling seed-borne diseases and seedling damping-off diseases by sowing seed rice and spraying the seeds immediately after sowing.

Conventional technology Until now, benzimidazole drugs, methyl! −
(n-butylcarbamoyl)-2-benzimidazole carbamate (benomyl), 2-(methoxycarbonylamino)benzimidazole (carpendazole), 2
-(4-thiazolyl)benzimidazole (TBZ)
, 1.2-bis(3-methoxycarbonyl-2-thioureido)benzene (thiophanate methyl), etc. are used as rice seed disinfectants, and one of these benzimidazole drugs and bis(dimethylthiocarbamoyl) disulfide. The use of a mixture with (thiuram) or N-)lichloromethylthiotetrahydrophthalimide (gialtan) as a rice seed disinfectant was published in the Pesticide Handbook 1989 Edition (Japan Plant Protection Association, 1989). No. 17 (published on November 20th)
7, page 157, pages 174-175, page 160, etc.).

In addition, 3-hydroxy-5-methylisoxazole (hereinafter referred to as "hymexazole") and methyl-N-(
2-methoxyacetyl)-N-(2,6xylyl)-D
A drug containing L-alanilate (hereinafter referred to as E-methaxyl j) as an active ingredient is mixed in advance with the rice seed before sowing, or
There is a method of irrigating immediately after sowing or after germination, and a method of mixing tetrachloroisophthalonitrile (hereinafter referred to as rTPNJ) with seedling growing soil or irrigating immediately after sowing or after germination.
1989 edition, p. 214, p. 164-165).

However, seed rice is sown without disinfecting it in advance, and seed disinfectants such as benomyl, benomyl/thiuram, thiophanate methyl, thio7anatemethyl/thiuram, and thiabendazole/xaltan are sprayed on the seed rice immediately after sowing. Until now, there have been no known methods for controlling seed-borne diseases and damping-off diseases.

Note that the benzimidazole drugs mentioned here are those that follow the classification of the pesticide handbook mentioned above, and include those that have a benzimidazole structure in terms of chemical structure.
It contains thiophanate methyl, which converts into benzimidazole compounds and exerts physiological effects after being sprayed on crops.

The invention tries to solve I! Conventionally, seed disinfection has been widely used to control seed-borne diseases of rice. In addition, to control seedling damping-off diseases, the seeds are sown after mixing the chemicals with seedling cultivation soil, or the chemicals are irrigated immediately after sowing or after germination. However, the work is complicated and time consuming, as it is necessary to soak the seeds in -. In addition, joint seedling raising is widely practiced as part of efforts to save labor in rice cultivation. Since the seed disinfection carried out here uses a large amount of chemical liquid, it is necessary to treat the residual liquid with lime or the like in order to prevent environmental pollution. Therefore, it is desired to establish a more labor-saving seed disinfection method in place of such conventional seed disinfection methods.

In view of the current situation, the present invention aims to provide a labor-saving method for disinfecting seeds.

2) Structure of the invention Means to solve problems The present inventors have made extensive studies to solve the above problems.

As a result, the seedlings were sown in seedling boxes (length: width: height -60 cm: 30C1l:3C1+) using the usual method without performing the conventional operations such as soaking, dusting, and spraying. Immediately after that, seed-borne diseases and damping-off diseases can be effectively controlled by spraying a benzimidazole-based drug alone or a diluted solution of a mixture of a benzimidazole-based drug and thiuram or xaltan on the surface of the seed rice. I found out what I can do.

That is, a solution containing 5 to 5000+ mg of a benzimidazole drug alone, calculated from the amount per seedling box, or a solution containing 5 to 5000 mg of these drugs, calculated from the top of the pigeon-legged seed rice immediately after sowing. 500011g and thiuram or kisa l
It has been found that a mixture of 5 to 3000 mg of Tan and a mixture of the two species exhibits a seed disinfection effect superior to that of a solution containing 5 to 3000 mg of Tan, and also effectively controls scale. In addition, this spraying treatment does not cause chemical damage to the rice, and compared to conventional seed disinfection at the edges, it does not require work such as soaking and air-drying the chemical solution, so it saves labor and does not leave any residual liquid as is the case with seed disinfection. There is no need for waste liquid treatment.

Here, the benzimidazole-based drugs that can be used in the present invention may be those that are generally used as disinfectants for seeds of agricultural crops, such as benomyl and thio7 as mentioned above.
These include methyl anate and thiabendazole.

Examples (control method) Examples of drugs that can be used in the labor-saving control method for rice diseases of the present invention are as follows. Newly formulated drugs may be used, but commercially available drugs can be used as they are. You can also. In other words, examples of single-dose benzimidazole drugs include bemimyl hydrating agent, thio7-abutmethyl hydrating agent,
Thiabendazole irrigation agents can be used. Examples of mixtures of these benzimidazole drugs and thiuram or cabtan agents include benomyl thiuram hydrating agent, thiophanate methyl, thiuram hydrating agent, thiophaneate gyaltan hydrating agent, and thiabendazole carbane hydrating agent. Tan hydrating agents or these flowable agents can be used.

The active ingredients of these drugs can range from 5 to 70% and can be used alone or in combination. When using these drugs, mix them with water for 10 to 70%.
Dilute it 1,000 times and use an appropriate spraying device to spread it into one of the seedling boxes.
20-500 * Q, preferably 50-200 per box (length: width: height - 60c shoulder = 30ctn: 3cm)
It is sufficient to dilute it twice and spray it on top of the pigeon leg-shaped seeds that have been sown in an amount of 40 to roomQ per box.

In addition, in the treatment method of the present invention, benzimidazole drugs and their thiurams or carbs? It can be sprayed by mixing the mixture with tan and other fungicides, insecticides, plant growth regulators, fertilizers, etc.

Next, examples of formulations of drugs used in the labor-saving pest control method of the present invention will be shown. In addition, all parts in the examples are parts by weight.

Formulation example 1 Wettable powder Benomyl 5
0 parts polyoxyethylene nonylphenyl ether 2
Sodium ligninsulfonate 3
Part white carbon 1
Division clay 4
4 parts The above composition is mixed uniformly and ground to obtain a wettable powder.

Formulation Example 2 Wettable powder Thio-7-a-non-methyl 75 parts Sodium dodecylbenzenesulfonate 2 parts Sodium ligninsulfonate 3 parts White carbon 1 part Clay 9 parts The above composition is homogenized, mixed, and ground to form an irrigation agent. get.

Formulation example 370 Able drug Benomyl 2
Part 0 Thiuram 2
0 parts polyoxyethylene nonylphenyl ether 1
IIs Sodium naphthalene sulfonate
2 parts xanthan gum 1% solution
10 parts water
37 parts ethylene glycol
After uniformly dissolving the above ingredients except 10 parts of the active ingredient, then adding the active ingredient and stirring well,
Wet grind in a sand mill to obtain a flowable agent.

Formulation Example 470 Able Agent Thiophanate methyl 30 parts Thiuram 15 parts Polyoxyethylene nonylphenyl ether II!
+su7 Sodium talenesulfonate 2
xanthan gum 1% aqueous solution 10
Department water
32 parts ethylene glycol
The above ingredients except for 10 parts of the active ingredient are uniformly dissolved, then the active ingredient is added, the mixture is inserted, and then wet-pulverized in a sand mill to obtain a 70% ablative agent.

In order to carry out a labor-saving method for controlling rice diseases using a flowable agent formulated as described above or a commercially available irrigation agent, it is best to carry out the following method. That is, the pigeon-leg-shaped rice seeds are sown in a seedling box after germination treatment according to the usual box seedling raising method, and then the above-mentioned chemical is diluted with water to adjust the concentration of the benzimidazole-based chemical. Then 200ppm
-25000pI)01. Preferably 1000pp+n
-10,000 ppm+n, and in the case of thiurams or kyatans, 300-15,000 ppm, preferably 1,500-6,000 ppm. In this case, the amount of sprayed chemical solution depends on the concentration of the chemical solution, but it is 20 m (2 to 200 m4, preferably 40 tn) per box.
Q~loOm12, and converting this to the amount of drug per box, in the case of benzimidazole drugs, it is 5tag~50
00mg preferably 9-1o00+mg for 40 shoulders, 5 for thiuram, cabtan
″in-3000mg, preferably 60119-600
There is mgT.

3) Effects of the invention When the pest control method of the present invention is implemented, the following results are brought about. That is, according to the pest control method of the present invention, if a diluted solution of a mixture of a benzimidazole drug or a benzimidazogamma monol drug and thiuram or cabtan is first sprayed on the tops of rice seeds immediately after sowing, rice blight and sesame leaf blight are caused. It is possible to effectively control seed-borne diseases such as rice blast and rice blast, and to effectively control seedling damping-off caused by bacteria of the genus Fusarium, bacteria of the genus Rhizonus, and bacteria of the genus Trichoderma.

Furthermore, when the method of controlling seeds according to the present invention is carried out, a high control effect is observed against Inakanae disease caused by Inakanae disease fungi resistant to benzimidazole drugs, for which conventional seed disinfection methods have insufficient control effects. In addition, the pest control method of the present invention is simpler than conventional seed disinfection methods because it is sufficient to simply spray a chemical solution onto the seed rice after sowing. Furthermore, since no residual chemical solution is left when the seeds are soaked, the effort of disposing of the solution can be saved, and there is no need to worry about environmental pollution.

Next, a test example will be shown to demonstrate the usefulness of the labor-saving method for controlling rice diseases according to the present invention.

Test Example 1 Effect on Inaka Nae Disease Rice rice affected by Inaka Nae Disease (seed rice of the variety "Kenryoku" (infected paddy rate: 48
%, ratio of benzimidazole drug-resistant bacteria in diseased rice grains (63%)) was soaked in water at 20°C for 4 days, drained, and germinated overnight at 32°C. 1 box (length: width/height = 60cm: 30cm
: 1509 seeds were sown per 3 cm) in terms of dry paddy. After sowing, use an automatic sprayer R (nozzle used: flat fan nozzle SS 8806) to apply a chemical solution containing a commercially available benzimidazole drug (single agent or mixture) diluted to a predetermined concentration at 50 + wff per seedling box. Distributed to.

After spraying, cover with soil and perform germination treatment at 32℃ for 2 days.
The plants were placed in a semi-shaded place in a greenhouse for one day, shielded from light by cheesecloth, and then the cheesecloth was removed and cultivation was managed as usual.

As the blue-yellow culture soil, commercially available Kumiai granular culture soil K (manufactured by Guju Kagaku Co., Ltd.) was used.

30 days after sowing, one-third of the seedling nursery box was investigated for the number of pathogenic bacteria showing symptoms of baka-seedling disease such as elongation and withering, and the number of bacteria showing disease-free seedling symptoms, and the rate of diseased seedlings (%) was calculated using the following formula. The control value (%) was determined.

In addition, regarding phytotoxicity, germination rate, growth level, etc. were observed and expressed as the following phytotoxicity level.

Pharmaceuticals: 12 no one: Sales Ten: Little + Ten: Middle +++: The Omoto exam was performed in the three -ward triple system, and the average control price ( %) was determined. The results are shown in Table 1.

Test Example 2 Effect on rice sesame leaf blight Rice seed rice affected with rice sesame leaf blight (seed rice of the variety "Nipponbare" (disease yield rate 34%)) was soaked in water at 20°C for 4 days, drained and heated at 32°C. Sprout the rice overnight, and put the seed rice that has a pigeon-leg shape into a seedling box (length and width: height: 160cm: 30cm).
: 150 g of dry rice was sown per 3 cm). After sowing, as in Test Example 1, a chemical solution containing a commercially available benzimidazole drug (single agent and mixture) diluted to a predetermined concentration was added to each seedling box at 50+if2.
Distributed to. The seedling box was managed in the same manner as in Test Example 1 after spraying.

21 days after sowing, one-third of the seedling boxes were investigated for the number of pathogenic bacteria with lesions of sesame leaf blight on the stems and leaves, and the number of bacteria with no disease symptoms, and the control value (%) was determined in the same manner as in Test Example 1. I asked for it. In addition, regarding phytotoxicity, germination rate, growth level, etc. were observed in the same manner as in Test Example 1, and the degree of phytotoxicity was indicated.

This test was conducted in three consecutive trials in one section, and the average control value (%) was determined. The results are shown in Table 2.

Test Example 3 Effect on rice blast disease Rice blast disease-affected paddy (variety [Sasanishiki]) (morbidity rate 45
%))) Soaked in water for 4 days at 20℃, drained and soaked in water for 3 days.
Sprout the seeds overnight at 2°C, and place the seed grains in a seedling box (length x width x height = 60crs: 30cm).
150 g of dry rice was sown per 3 cm). After sowing, in the same manner as in Test Example 1, a commercially available benzimidazole drug diluted to a predetermined concentration was sprayed onto the seedlings in an area of 50 m12 per seedling box. The seedling box was managed in the same manner as in Test Example 1 after spraying.

14 days after sowing, one-third of the seedling boxes were investigated for the number of pathogenic bacteria and the number of disease-free microorganisms in which lesions of rice blast disease were observed on the stems and leaves, and the control value (%) was determined in the same manner as in Test Example 1. I asked for it.

In addition, as for phytotoxicity, germination rate, growth level, etc. were observed in the same manner as in Test Example 1, and the degree of phytotoxicity was indicated.

This test was conducted in three consecutive trials in one section, and the average control value (%) was determined. The results are shown in Table 3.

Trial M Example 4: Effect on rice stand blight caused by Trichoderma fungus. Paddy of the variety "Kyodo" that had fallen down due to wind and rain was soaked in water at 20°C for 4 days, drained, and germinated overnight at 32°C, resulting in pigeon-legged appearance. Seed rice in one box for raising seedlings (length: width: height - 60cm)
c+*: 30cm: 3cm) 150g of dry rice was sown per area. After sowing, as in Test Example 1, a commercially available benzimidazole drug diluted to a predetermined concentration was sprayed at 50+z12 per seedling box. Next, Trichoderma oryzae (Trichoderma oryzae), which had been cultured in advance on a potato glucose agar medium at 24°C for 5 days, was grown.
Water was added to the spores of the bacteria to adjust the concentration of spores to about 105 per milliliter, and 50 milliliters of the spores were added per liter of seedling growing medium and mixed well. After the spraying, the soil was covered with this seedling growing soil, and the seedling growing box was managed in the same manner as in Test Example 1 after the spraying.

In addition, the seedling growing soil is made of Fusarium genus bacteria (Fusarium spp.
We used field soil contaminated with p.

21 days after sowing, one-third of the seedling boxes were investigated for the number of disease-causing bacteria and the number of disease-free fungi, which indicate the presence of seedling damping-off.
The control value (%) was determined in the same manner as Test Example 1. In addition, regarding phytotoxicity, germination rate, degree of phytotoxicity, etc. were observed in the same manner as in Test Example 1, and the degree of phytotoxicity was indicated.

This test was conducted in three consecutive trials in one section, and the average control value (%) was determined. The results are shown in Table 4.

Test Example 5 Against rice rot caused by rice blight bacteria. Rice seeds infected with rice blight bacterium Seed rice of the variety "Asahi" (disease yield rate 35%) was soaked in water at 20°C for 4 days, drained and heated at 32°C. After germination overnight, seed rice with a pigeon-leg shape is placed in a seedling box (vertical:
Width: Height - 60cm + m: 30cm: 3c stomach) Sowing rem for 150g in terms of dry paddy.

After sowing, as in Test Example 1, add 50 mQ of commercially available benzimidazole-based chemicals diluted to a specified concentration per seedling box.
Scattered to:. The seedling box was managed in the same manner as in Test Example 1 after spraying.

14 days after sowing, one-third of the seedling boxes were investigated for the number of pathogenic bacteria and the number of disease-free microorganisms, which indicate the presence of seedling damping-off.
The control value (%) was determined in the same manner as Test Example 1. In addition, regarding phytotoxicity, germination rate, growth level, etc. were observed in the same manner as Test Example I, and the degree of phytotoxicity was indicated.

This test was conducted in three consecutive trials in one section, and the average control value (%) was determined. The results are shown in Table 5.

Procedural amendment (voluntary) February S, 1992

Claims (1)

[Claims] A rice disease prevention method characterized by spraying a diluted solution of a benzimidazole drug or a mixture of a benzimidazole drug and bis(dimethylthiocarbamoyl) disulfide or N-trichloromethylthiotetrahydrophthalimide to rice seeds immediately after sowing in a nursery box. Labor-saving pest control method.