Pleuromutilin wettable powder and its preparation method

Abstract

The present invention relates to a pleuromutilin wettable powder and a method for preparing the same. The pleuromutilin wettable powder contains 5-25 wt% pleuromutilin, 2-6 wt% wetting and dispersing agent, and the remainder a filler. The raw materials are pulverized in an airflow mill to a particle size of less than 325 mesh to obtain a 5-25% pleuromutilin wettable powder. The 5-25% pleuromutilin wettable powder can be used to prevent and treat various agricultural diseases, such as the pathogen of rice bacterial leaf blight.

Description

[Technical Field]

[0001] The present invention belongs to the field of pesticide wettable powders, and more particularly to a pleuromutilin wettable powder for preventing and treating plant bacterial diseases. [Background technology]

[0002] Bacterial plant diseases are classified as the second-class plant disease, second only to viruses, and are characterized by rapid onset, widespread distribution, and difficulty in control. In recent years, due to changes in China's agricultural cultivation system and environmental climate, bacterial crop diseases such as rice bacterial leaf blight (Xoo), rice streak (Xoc), citrus canker (Xac), cabbage black rot, peach hole, Chinese cabbage soft rot, muskmelon angular spot, tobacco bacterial wilt, watermelon fruit rot, and tomato bacterial wilt have become increasingly prevalent in China. Chemical pesticides are the primary means of control for bacterial plant diseases, with copper compounds being the most widely used. However, copper compounds have poor safety profiles and are prone to copper poisoning. Currently, there is a severe shortage of highly effective and safe chemical agents for prevention and treatment, resulting in significant losses in agricultural production.

[0003] Pleuromutilin wettable powder is a new eco-friendly fungicide independently developed by Guizhou University. It is characterized by high efficiency, low toxicity and low risk. It has excellent antibacterial activity against pathogens such as Xanthomonas oryzae (Xoo), Bacterial streak fungus (Xoc), Xanthomonas citri (Xac), Cabbage black rot fungus, Peach needle hole fungus, Chinese cabbage soft rot fungus, Muskmelon angular spot fungus, Bacterial wilt fungus of tobacco, Watermelon fruit rot fungus, Tomato bacterial wilt fungus, Cucumber bacterial leaf blight fungus, Amorphophallus konjac, Grapevine canker fungus, Tomato canker fungus, Kiwi canker fungus, Apple canker fungus, Cucumber gray mold fungus, Pepper wilt fungus, Brassica napus, Wheat scab fungus, Potato late blight fungus and Blueberry root rot fungus. At a dosage of 200 μg / mL, it has excellent preventive effects against bacterial diseases such as rice bacterial leaf blight, rice bacterial streak, and citrus canker. Summary of the Invention

[0004] To solve the problems of the prior art, the formulation of the pleuromutilin wettable powder provided by the present invention contains 5 to 25 wt% pleuromutilin, 2 to 6 wt% wetting and dispersing agent, and the remainder is a filler. The preferred pleuromutilin concentrations are 5 to 20 wt%, 5 to 10 wt%, 10 to 25 wt%, and 10 to 20 wt%, and most preferably 10 wt% and 20 wt%.

[0005] The wetting and dispersing agent selected in this application is selected from sodium lignosulfonate, calcium lignosulfonate, TERSPERSE 2020, Morwet D425, sodium methylenebisnaphthalenesulfonate, and WP410, either singly or in combination.

[0006] The filler is selected from the group consisting of diatomaceous earth, bentonite, kaolin, white carbon, and light calcium, or a mixture of these.

[0007] The innovations of this patent are as follows: The main significance of the developed formulation is that, through extensive screening of wetting and dispersing agents, etc., a product is prepared that effectively improves the preventive effect of the pleuromutilin wettable powder active ingredient against plant bacterial diseases. Compared with the patent (ZL 202111389716.1), the pleuromutilin wettable powder prepared by this invention has better and broader spectrum activity against plant bacterial diseases, reducing the amount of chemical pesticide fertilizer used and increasing its effectiveness. [Brief explanation of the drawings]

[0008] [Figure 1] The protective activity of 10% pleuromutilin wettable powder against Xanthomonas oryzae was 200 μg / mL. [Figure 2] The therapeutic activity of 10% pleuromutilin wettable powder against rice bacterial leaf blight fungus was 200 μg / mL. [Figure 3] The protective activity of 10% pleuromutilin wettable powder against rice streak fungus was 200 μg / mL. [Figure 4]The therapeutic activity of 10% pleuromutilin wettable powder against rice streak fungus was 200 μg / mL. [Figure 5] The protective activity of 10% pleuromutilin wettable powder against Xanthomonas campestris pv. citri was 200 μg / mL. [Figure 6] The therapeutic activity of 10% pleuromutilin wettable powder against citrus canker fungus was 200 μg / mL. DETAILED DESCRIPTION OF THE INVENTION

[0009] Example The present invention will be further explained by examples. It should be understood that the methods described in the examples of the present invention are merely for the purpose of illustrating the present invention, and are not intended to limit the present invention, and any simple improvements to the preparation methods of the present invention based on the concept of the present invention are all within the scope of the present invention. All raw materials and solvents used in the examples are commercially available products of reasonable purity.

[0010] Example 1: Optimization of the preparation method for 10% pleuromutilin wettable powder First, other additives were fixed, and diatomaceous earth, bentonite, kaolin, and light calcium filler were selected. Wettable powders were prepared according to the above method, and their suspension rate (National Standard of the People's Republic of China GB / T 14825-2006), wetting time (National Standard of the People's Republic of China GB / T 5451-2001), and fineness (passing through a 45 μm test sieve, %) were measured. The results are shown in Table 1. [Table 1] JPEG0007799366000001.jpg44170Table 1 shows that light calcium + white carbon had the best suspension rate, followed by light calcium, and then diatomaceous earth. Looking at the wetting time, light calcium + white carbon, light calcium, and bentonite had short wetting times and fast wetting speeds. Therefore, light calcium + white carbon was fixed, and the wetting agent and dispersant were measured. The results are shown in Table 2. [Table 2] JPEG0007799366000002.jpg60170As shown in Table 2, WP410 and calcium lignosulfonate had the best wettability, followed by Morwet D425, with the other additives having poor wettability.WP410 had the best dispersibility, followed by calcium lignosulfonate, with the other additives having average dispersibility.WP410 had the best fineness.

[0011] Based on the above optimization results, a 10% pleuromutilin wettable powder was prepared according to Example 1 using light calcium + white carbon as the filler and WP410 as the wetting and dispersing agent, and then crushed to 3 to 15 μm. The resulting powder is shown in Table 3. [Table 3] JPEG0007799366000003.jpg63170

[0012] Example 2: Preparation of 10% pleuromutilin wettable powder [Table 4] JPEG0007799366000004.jpg38170(1) 10.21 g of pleuromutilin, 4.0 g of WP410, 8.0 g of white carbon and 77.79 g of light calcium are sequentially added to a first mixing kettle, and stirring is started and continued for 30 minutes. (2) Start the airflow pulverizer to pulverize the material, and then place the pulverized material in the second mixing kettle. After pulverization is complete, clean up the pipeline, the mixing kettle, and the material in the pulverizer. Place the cleaned-up material in the second mixing kettle, start the mixer, and continue pulverizing until the material is 325 mesh or less to obtain a 10% pleuromutilin wettable powder.

[0013] Example 3: Preparation of 20% pleuromutilin wettable powder [Table 5] JPEG0007799366000005.jpg38170(1) Pleuromutilin (20.41 g), WP410 (5.2 g), white carbon (9.6 g), and light calcium (64.79 g) were added in this order to a first mixing vessel, and stirring was started and continued for 30 minutes. (2) The airflow pulverizer is started to pulverize the material, and the pulverized material is placed in the second mixing kettle. After pulverization is complete, the pipelines, the mixing kettle, and the material in the pulverizer are cleaned up, and the cleaned-up material is placed in the second mixing kettle. The mixer is started, and pulverization is continued until the particle size is smaller than 325 mesh to obtain a 20% pleuromutilin wettable powder.

[0014] Example 4: In vitro test of pesticide efficacy In this study, the turbidity method was used to evaluate the antibacterial EC of pleuromutilin wettable powder against ten species of bacteria: Xanthomonas oryzae (Xoo), Bacterial streak fungus of rice (Xoc), Xanthomonas oryzae (Xac), Cabbage black rot fungus, Peach hole fungus, Chinese cabbage soft rot fungus, Muskmelon angular spot fungus, Tobacco bacterial wilt fungus, Watermelon fruit rot fungus, and Tomato bacterial wilt fungus. 50 Measure the value. 1. Test materials: Gun heads (5 mL, 1 mL, 200 μL), 15 mL centrifuge tubes, doubly distilled water, 2 mL EP tubes, and NB medium must all be sterilized. 2. NB medium: 3 g of beef peptone, 5 g of peptone, 1 g of yeast powder, 10 g of glucose, and 1 L of doubly distilled water were dispensed into test tubes (4 mL per tube), and the pH was adjusted to 7.0 to 7.2. 3, Operation steps: (1) A fixed amount of the formulation to be tested was weighed and dissolved in the corresponding volume (200 μL) of DMSO. A 5% solution system was prepared, diluted proportionally to the required concentration, and adjusted to 4 mL with 0.1% Tween solution. (2) 1 mL of the twin drug mixture solution was aspirated using a pipette and placed in a test tube containing 4 mL of culture medium. (3) 200 μL of the mixed solution (culture medium) was aspirated using a pipette, and the OD value was measured and recorded in a 96-well plate. (4) 50 μL of bacterial suspensions of bacterial leaf blight fungus (Xoo), bacterial streak fungus (Xoc), bacterial canker fungus (Xac), cabbage black rot fungus, peach needle hole fungus, Chinese cabbage soft rot fungus, muskmelon angular spot fungus, tobacco bacterial wilt fungus, watermelon fruit rot fungus, and tomato bacterial wilt fungus were added to each test tube. (5) A shaker was placed in the flask and set to 28°C and 180 rpm. (6) After 24-36 hours (the OD value of CK was 0.6-0.8 (indicating that the produced bacteria were not contaminated and were growing normally)), the OD value was measured and recorded, and the inhibition rate was calculated. Corrected OD value = OD value of bacteria-containing medium - OD value of sterile medium Inhibition rate % = (OD value of bacterial solution in control medium after correction - OD value of bacterial-containing medium after correction) / OD value of bacterial solution in control medium after correction * 100 4. Activity data: The different formulations showed excellent antibacterial activity against ten bacterial diseases, including rice bacterial leaf blight fungus (Xoo), and their EC 50 The values ​​are superior to the control drugs 20% thiadiazole zinc suspension, 20% thiadiazole copper suspension, 95% pleuromutilin bulk drug, and 10% pleuromutilin wettable powder. [Table 6] JPEG0007799366000006.jpg50170As can be seen from Table 6, the 10% pleuromutilin wettable powder of the present invention has an EC 50 The EC values ​​were 0.83 μg / mL, respectively. 50 All values ​​were superior to the control drugs 20% thiadiazole zinc suspension (13 μg / mL), 20% thiadiazole copper suspension (76.27 μg / mL), 12% Zhongshengmycin powder (85.16 μg / mL), and 98% pleuromutilin drug substance (1.33 μg / mL). [Table 7] JPEG0007799366000007.jpg50170As can be seen from Table 7, the 10% pleuromutilin wettable powder of the present invention has an EC 50 The EC values ​​were 0.88 μg / mL, respectively. 50 All values ​​were superior to the control drugs 20% thiadiazole zinc suspension (29.11 μg / mL), 20% thiadiazole copper suspension (77.30 μg / mL), 12% chungshenmycin powder (60.75 μg / mL), and 98% pleuromutilin drug substance (1.04 μg / mL). [Table 8] As can be seen from Table 8, the 10% pleuromutilin wettable powder of the present invention has an EC 50 The EC values ​​were 1.84 μg / mL, respectively. 50 All values ​​were superior to the control drugs 20% thiadiazole zinc suspension (41.97 μg / mL), 20% thiadiazole copper suspension (104.89 μg / mL), 12% chungshenmycin powder (108.51 μg / mL), and 98% pleuromutilin drug substance (2.87 μg / mL). [Table 9] As can be seen from Table 9, the 10% pleuromutilin wettable powder of the present invention has an EC 50 The EC values ​​were 11.85 μg / mL, respectively. 50 All values ​​were superior to the control drugs 20% thiadiazole zinc suspension (55.41 μg / mL), 20% thiadiazole copper suspension (82.27 μg / mL), 12% chungshenmycin powder (92.61 μg / mL), and 98% pleuromutilin drug substance (14.48 μg / mL). [Table 10] JPEG0007799366000010.jpg50170As can be seen from Table 10, the 10% pleuromutilin wettable powder of the present invention has an EC 50 The EC values ​​were 17.71 μg / mL, respectively. 50 All values ​​were superior to the control drugs 20% thiadiazole zinc suspension (82.54 μg / mL), 20% thiadiazole copper suspension (263.87 μg / mL), 12% chungshenmycin powder (146.78 μg / mL), and 98% pleuromutilin drug substance (24.80 μg / mL). [Table 11] JPEG0007799366000011.jpg50170As can be seen from Table 11, the 10% pleuromutilin wettable powder of the present invention has an EC 50 The EC values ​​were 21.31 μg / mL, respectively. 50All values ​​were superior to the control drugs 20% thiadiazole zinc suspension (30.56 μg / mL), 20% thiadiazole copper suspension (131.32 μg / mL), 12% chungshenmycin powder (136.50 μg / mL), and 98% pleuromutilin drug substance (28.89 μg / mL). [Table 12] JPEG0007799366000012.jpg50170As can be seen from Table 12, the 10% pleuromutilin wettable powder of the present invention has an EC 50 The EC values ​​were 42.62 μg / mL, respectively. 50 All values ​​were superior to the control drugs 20% thiadiazole zinc suspension (65.41 μg / mL), 20% thiadiazole copper suspension (156.40 μg / mL), 12% chungshenmycin powder (135.42 μg / mL), and 98% pleuromutilin drug substance (52.17 μg / mL). [Table 13] As can be seen from Table 13, the 10% pleuromutilin wettable powder of the present invention has an EC 50 The EC values ​​were 31.62 μg / mL, respectively. 50 All values ​​were superior to the control drugs 20% thiadiazole zinc suspension (50.50 μg / mL), 20% thiadiazole copper suspension (101.23 μg / mL), 12% chungshenmycin powder (122.95 μg / mL), and 98% pleuromutilin drug substance (33.31 μg / mL). [Table 14] JPEG0007799366000014.jpg50170As can be seen from Table 14, the 10% pleuromutilin wettable powder of the present invention has an EC 50 The EC values ​​were 8.36 μg / mL, respectively. 50 All values ​​were superior to the control drugs 20% thiadiazole zinc suspension (88.81 μg / mL), 20% thiadiazole copper suspension (97.46 μg / mL), 12% chungshenmycin powder (110.33 μg / mL), and 98% pleuromutilin drug substance (60.99 μg / mL). [Table 15] JPEG0007799366000015.jpg50170As can be seen from Table 15, the 10% pleuromutilin wettable powder of the present invention has an EC 50 The EC values ​​were 40.65 μg / mL, respectively. 50 All values ​​were superior to the comparators 20% thiadiazole zinc suspension (83.01 μg / mL), 20% thiadiazole copper suspension (132.92 μg / mL), and 98% pleuromutilin drug substance (53.03 μg / mL).

[0015] Example 5: Efficacy test of potted rice bacterial leaf blight live pesticide This time, the leaf cutting method was used to measure the protective and curative effects of the 10% pleuromutilin wettable powder of the present invention at a concentration of 200 μg / mL on potted rice plants infected with bacterial leaf blight. Therapeutic activity: Using scissors coated with the rice bacterial leaf blight solution, a 1 / 3cm section of the leaf tip was cut off. After 24 hours, a 10% pleuromutilin wettable powder of the present invention was selected and dissolved with DMSO. A 200μg / mL concentration of the drug was then prepared with a 0.1% Tween-80 solution. This drug was sprayed evenly onto the rice leaves until droplets fell off. At the same time, a control spray of pure water without any drug was set aside. Ten to fifteen leaves were treated for each rice plant. Fourteen days after drug administration, the length of the lesions on the rice leaves was measured, and the preventive and therapeutic effect was calculated based on the length of the lesions. [Number 1] JPEG0007799366000016.jpg11170 Protective activity: The 10% pleuromutilin wettable powder of the invention was selected and dissolved in 200 μL of DMSO. Then, a 200 μg / mL solution was added to a 0.1% Tween-80 solution to prepare a drug. This was sprayed evenly onto rice leaves until droplets formed. After 24 hours, the leaves were cut with scissors and inoculated with the rice bacterial leaf blight fungus. The fungus solution was placed in the tip third of the rice leaf. A control group was also set up with untreated water. Each treatment involved 10-15 leaves, and the treatment was repeated three times. 14 days after application, the length of the lesions on the rice leaves was measured, and the preventive and therapeutic effects were calculated based on the length of the lesions. [Number 2] JPEG0007799366000017.jpg11170[Table 16] JPEG0007799366000018.jpg50170From Table 16 and Figure 1, at a concentration of 200 μg / mL, the protective activity of 10% pleuromutilin wettable powder against rice bacterial leaf blight was 51.4%, both of which were superior to those of 20% thiadiazole copper suspension (44.8%) and 12% zhongshenmycin powder (25.4%). [Table 17] JPEG0007799366000019.jpg50170As can be seen from Table 17 and Figure 2, at a concentration of 200 μg / mL, the therapeutic activity of the 10% pleuromutilin wettable powder of the present invention against rice bacterial leaf blight was 45.6%, both of which were superior to the 20% thiadiazole copper suspension (37.6%) and the 12% zhongshenmycin dust (21.3%).

[0016] Example 6: Pesticide efficacy test on live potted rice streak bacterial disease When the concentration is 200μg / mL, the protective effect of 10% pleuromutilin wettable powder against rice streak bacterial disease in living potted plants is measured using the osmotic pressure method. Protective activity: Using an analytical balance, accurately measure 10% pleuromutilin wettable powder and control agent into 1.5mL centrifuge tubes, add 200μL of DMSO, and dissolve each. Then, mix each with 0.1% Tween-20 solution to a concentration of 200μg / mL. Spray evenly onto rice leaves until droplets form. After 24 hours, fill a syringe without a needle with the fungal solution and inject it into the rice plants approximately one-third of the way from the leaf tip. Simultaneously, set up a control with clear water without any fungicide. Each treatment involved 10-15 leaves, and repeat the process three times. 14 days after treatment, measure the length of the lesions on the rice leaves, and calculate the disease index and preventive efficacy. Preventive treatment effect = (lesion length of negative control group - lesion length of treatment group) / lesion length of negative control group × 100% Therapeutic activity: The fungal solution was filled into a needleless syringe and injected into rice plants approximately one-third of the way from the leaf tip. 24 hours later, an analytical balance was used to accurately measure 10% pleuromutilin wettable powder and a control agent into 1.5mL centrifuge tubes. 200μL of DMSO was added to each and dissolved. Each agent was then mixed with a 0.1% Tween-20 solution at a concentration of 200μg / mL and sprayed evenly onto rice leaves until droplets fell. A control was also set up with untreated water. 10-15 leaves were treated for each treatment, and the treatment was repeated three times. 14 days after application, the length of the lesions on the rice leaves was measured, and the disease index and preventive efficacy were calculated. Preventive treatment effect = (lesion length of negative control group - lesion length of treated group) / lesion length of negative control group × 100% [Table 18] 3, at a concentration of 200 μg / mL, the protective activity of the 10% pleuromutilin wettable powder of the present invention against rice streak pathogen is 37.4%, of which the activity of the 10% pleuromutilin wettable powder of the present invention (44.1%) against rice streak pathogen is superior to that of the 20% thiadiazole copper suspension (34.4%) and the 12% zhongshenmycin powder (18.7%), and is equivalent to that of the 20% thiadiazole zinc suspension (38.5%). [Table 19] JPEG0007799366000021.jpg50170As can be seen from Table 19 and Figure 4, at a concentration of 200 μg / mL, the therapeutic activity of the 10% pleuromutilin wettable powder of the present invention against rice streak fungus is 39.5%, which is superior to the 20% thiadiazole copper suspension (30.0%) and the 12% zhongshenmycin powder (19.3%) and is equivalent to the 20% thiadiazole zinc suspension (42.5%).

[0017] Example 7: Citrus canker fungus live potted plant pesticide efficacy test When the concentration is 200 μg / mL, the protective and curative effects of the pleuromutilin wettable powder of the present invention on potted plants against citrus canker pathogen are measured using the needle puncture method. protective activity Accurately measure 18.0 mg of 20% pleuromutilin wettable powder using an analytical balance, add 200 μL of DMSO, dissolve each, and mix with 0.1% Tween-80 solution to a concentration of 200 μg / mL. Spray evenly onto rice leaves until droplets fall. After 24 hours, inoculate with a disposable syringe containing Xanthomonas campestris pv. citri, puncture 18 small holes per leaf, and inject Xac suspension (OD ). 595 A new filter paper soaked in ethanol (=0.6) was applied to the wound surface for 24 hours. The filter paper containing the drug was discarded, and a control was set up using clean water without any drug added. 10 to 15 leaves were treated for each treatment, and this was repeated three times. 21 days after drug administration, the disease status of the citrus leaves was measured, and the preventive treatment was calculated based on the diameter of the inhibition zone. [Number 3] JPEG0007799366000022.jpg11170 Therapeutic activity The leaves were inoculated with a disposable syringe containing Xanthomonas campestris pv. citri, and 18 small holes were punctured in each leaf, followed by the injection of a Xanthomonas campestris suspension (OD ). 595 After applying fresh filter paper soaked in DMSO (pH 7.0 = 0.6) to the wound surface for 24 hours, an analytical balance was used to accurately measure out 18.0 mg of 20% pleuromutilin suspension, dissolve each in DMSO, and then prepare a 200 μg / mL solution in 0.1% Tween-80 solution. This was sprayed evenly onto the citrus leaves until droplets fell, while a control of pure water without any drug was also used. Ten to fifteen leaves per citrus plant were treated. 21 days after drug administration, the disease status of the citrus leaves was measured, and the preventive treatment effect was calculated based on the diameter of the inhibition zone. [Number 4] JPEG0007799366000023.jpg11170[Table 20] JPEG0007799366000024.jpg50170As can be seen from Table 20 and Figure 5, at a concentration of 200 μg / mL, the protective activity of the 10% pleuromutilin wettable powder of the present invention against citrus canker fungus is 45.4%, which is superior to the 20% thiadiazole copper suspension (39.7%) and the 12% zhongshenmycin powder (20.1%), and equivalent to the activity of the 20% thiadiazole zinc suspension (45.8%) and the 98% pleuromutilin drug substance (44.9%). [Table 21] JPEG0007799366000025.jpg50170From Table 21 and Figure 6, at a concentration of 200 μg / mL, the therapeutic activity of the 10% pleuromutilin wettable powder of the present invention against citrus canker fungus is 45.7%, which is superior to the 20% thiadiazole copper suspension (36.5%) and the 12% zhongshenmycin powder (37.4%), and is equivalent to the activity of 98% pleuromutilin bulk drug (47.9%) and 20% thiazole zinc suspension (48.2%).

Claims

1. Use of a pleuromutilin wettable powder in agricultural pest control, The pleuromutilin wettable powder contains 5 to 25 wt % of pleuromutilin, 2 to 6 wt % of a wetting and dispersing agent, and the remainder is a filler, The wetting and dispersing agent is selected from the group consisting of sodium lignin sulfonate, calcium lignin sulfonate, alkyl naphthalene sulfonate, sodium polynaphthalene sulfonate, sodium methylene bisnaphthalene sulfonate, and sulfonated natural coconut oil fatty alcohol, or a mixture of these. The filler is selected from the group consisting of diatomaceous earth, bentonite, white carbon, and light calcium, or a mixture of these fillers; 1. The use of a pleuromutilin wettable powder in the field of agricultural pest control, wherein the agricultural pest is at least one of Xanthomonas oryzae (Xoo), bacterial rice streak (Xoc), Xanthomonas citri (Xac), cabbage black rot fungus, peach needle hole fungus, Chinese cabbage soft rot fungus, muskmelon bacterial angular spot fungus, tobacco bacterial wilt fungus, watermelon fruit rot fungus, tomato bacterial wilt fungus, cucumber bacterial leaf blight fungus, konjac bacterial leaf blight fungus, grape canker fungus, tomato canker fungus, kiwi canker fungus, apple canker fungus, cucumber Botrytis cinerea, chili pepper wilt fungus, rape sclerotinia rot fungus, wheat scab fungus, potato phytophthora infestans, and blueberry root rot fungus.

2. A method for controlling agricultural pests using a pleuromutilin wettable powder, comprising: The pleuromutilin wettable powder contains 5 to 25 wt % of pleuromutilin, 2 to 6 wt % of a wetting and dispersing agent, and the remainder is a filler, The wetting and dispersing agent is selected from the group consisting of sodium lignin sulfonate, calcium lignin sulfonate, alkylnaphthalene sulfonate, sodium polynaphthalene sulfonate, sodium methylenebisnaphthalene sulfonate, and sulfonated natural coconut oil fatty alcohols, or a mixture of these. The filler is selected from the group consisting of diatomaceous earth, bentonite, white carbon, and light calcium, or a mixture of these fillers; 1. A method for controlling agricultural pests, comprising applying the pleuromutilin wettable powder to a harmful substance or its living environment, wherein the harmful substance is at least one of bacterial leaf blight fungus (Xoo), bacterial rice streak fungus (Xoc), Xanthomonas campestris pv. citri (Xac), cabbage black rot fungus, peach hole fungus, Chinese cabbage soft rot fungus, muskmelon bacterial angular spot fungus, tobacco bacterial wilt fungus, watermelon fruit rot fungus, tomato bacterial wilt fungus, cucumber bacterial leaf blight fungus, konjac bacterial leaf blight fungus, grape canker fungus, tomato canker fungus, kiwi canker fungus, apple canker fungus, cucumber Botrytis cinerea, chili pepper wilt fungus, rape sclerotinia rot fungus, wheat scab fungus, potato phytophthora infestans, and blueberry root rot fungus.

3. 1. A method for protecting plants from agricultural pests, comprising the step of contacting agricultural pests with a pleuromutilin wettable powder, The pleuromutilin wettable powder contains 5 to 25 wt % of pleuromutilin, 2 to 6 wt % of a wetting and dispersing agent, and the remainder is a filler, The wetting and dispersing agent is selected from the group consisting of sodium lignin sulfonate, calcium lignin sulfonate, alkylnaphthalene sulfonate, sodium polynaphthalene sulfonate, sodium methylenebisnaphthalene sulfonate, and sulfonated natural coconut oil fatty alcohols, or a mixture of these. The filler is selected from the group consisting of diatomaceous earth, bentonite, white carbon, and light calcium, or a mixture of these fillers; 1. A method for protecting plants from agricultural pests, wherein the agricultural pest is at least one of Xanthomonas oryzae (Xoo), bacterial rice streak (Xoc), Xanthomonas citri (Xac), cabbage black rot fungus, peach needle hole fungus, Chinese cabbage soft rot fungus, muskmelon bacterial angular spot fungus, tobacco bacterial wilt fungus, watermelon fruit rot fungus, tomato bacterial wilt fungus, cucumber bacterial leaf blight fungus, konjac bacterial leaf blight fungus, grape canker fungus, tomato canker fungus, kiwi canker fungus, apple canker fungus, cucumber Botrytis cinerea, chili pepper wilt fungus, rape sclerotinia rot fungus, wheat scab fungus, potato phytophthora infestans, and blueberry root rot fungus.

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