Compound bactericide formula for preventing and treating powdery mildew of Lanzhou honey dew melons and prevention and treatment method

Abstract

The invention relates to the technical field of pesticides, and discloses a compound bactericide formula for preventing and treating powdery mildew of Lanzhou honey dew melons, which is characterized by comprising 10-20 parts of difenoconazole active compound, 10-20 parts of azoxystrobin active compound, 50-70 parts of solvent, 3-8 parts of emulsifier, 3-8 parts of dispersant, 2-5 parts of stabilizer, 0.2-0.8 part of thickener and 0.1-0.5 part of defoaming agent. The total amount of the difenoconazole and azoxystrobin suspending agent is 100 parts. According to the compound bactericide formula for preventing and treating powdery mildew of Lanzhou honey dew melons and the prevention and treatment method, a difenoconazole-azoxystrobin suspending agent formula is adopted, the bactericidal spectrum is expanded, soil treatment and seedling treatment are carried out before planting, spraying treatment is carried out in the planting process, and the effect of preventing and treating powdery mildew of the Lanzhou honey dew melons is achieved. Various fungal diseases possibly encountered in the growth process of the Lanzhou honey dew melons can be effectively prevented and treated, and more comprehensive protection is provided for plant growth.

Description

Technical Field

[0001] The invention relates to the technical field of pesticides, and in particular to a compound fungicide formula for preventing and controlling powdery mildew of Lanzhou white melon and a prevention and control method. Background Art

[0002] Powdery mildew of honeydew melon is a common disease of honeydew melon. Generally, the old leaves at the bottom of the melon vine are first affected, and then gradually spread upwards. In severe cases, the lesions are densely covered, and the entire leaf turns yellow. The leaves of the diseased honeydew melon plant will be covered with white powder, which hinders the normal photosynthesis of the leaves, causing the plant to age prematurely, greatly affecting the quality and yield of the honeydew melon.

[0003] In addition to harming white melon, white melon powdery mildew can also harm cucurbit vegetables such as watermelon, melon, and zucchini. White melon powdery mildew is more common in melon single capsule. The optimum temperature for the pathogen is 20-25℃. Under the condition of air relative humidity of about 25%, the disease can also occur and spread. The pathogen overwinters in the soil with the diseased remains in the form of closed capsules, or it can overwinter on crops as mycelium and conidia. When the temperature reaches 20-25℃, the closed capsules emit ascospores, or form conidiophores and conidia from the hyphae, which are spread with the help of rain or air flow. After the disease occurs, the conidia produced on the lesions can be reinfected many times. It occurs all year round in all white melon planting areas and is one of the main diseases of white melon. The yield of white melon is reduced by 20% to 50% every year due to powdery mildew. Powdery mildew, a seemingly routine disease, has become increasingly difficult to prevent in recent years. Especially in greenhouses with continuous cropping, high field planting density, poor ventilation and light transmission, and high humidity, the disease is more serious. With the development of agricultural modernization, the planting scale continues to expand and the multiple cropping index continues to increase, causing the powdery mildew of honeydew melon to become more serious. Since the fungus can infect the honeydew melon throughout its growth period, the prevention and control effect of powdery mildew is poor. The development of new, safe, efficient, and environmentally friendly compound fungicides conforms to the development direction of fungicides and is of great significance to the safe production of honeydew melon. Summary of the invention

[0004] The invention provides a compound fungicide formula for preventing and controlling powdery mildew of Lanzhou white melon and a prevention and control method. The formula of difenoconazole-myclobutanil suspension is adopted to expand the fungicide spectrum, and soil treatment and seedling treatment are performed before planting, and spray treatment is performed during the planting process. The formula can effectively prevent and control various fungal diseases that may be encountered during the growth of Lanzhou white melon, and provide more comprehensive protection for plant growth.

[0005] The invention provides a compound fungicide formula for preventing and controlling powdery mildew of Lanzhou white melon, comprising 10-20 parts of difenoconazole technical, 10-20 parts of azoxystrobin technical, 50-70 parts of solvent, 3-8 parts of emulsifier, 3-8 parts of dispersant, 2-5 parts of stabilizer, 0.2-0.8 parts of thickener and 0.1-0.5 parts of defoamer, to prepare a difenoconazole-azoxystrobin suspension with a total amount of 100 parts.

[0006] Furthermore, the solvent is deionized water, the emulsifier is alkylphenol polyoxyethylene ether, the dispersant is lignin sulfonate, the stabilizer is ethylene glycol, the thickener is xanthan gum, and the defoamer is an organosilicon defoamer.

[0007] Furthermore, the preparation steps of the difenoconazole-azoxystrobin suspension are as follows:

[0008] S101, and weighing 6 parts of alkylphenol polyoxyethylene ether, 5 parts of lignin sulfonate, 3 parts of ethylene glycol, 0.5 parts of xanthan gum and 0.5 parts of silicone defoamer;

[0009] S102, weighing 15 parts of difenoconazole technical drug and 15 parts of azoxystrobin technical drug of set purity and mass, adding 55 parts of deionized water in a container with a stirring device, turning on the stirring, slowly adding 5 parts of lignin sulfonate dispersant weighed, stirring evenly, and fully dissolving them in the water;

[0010] S103, adding difenoconazole technical and azoxystrobin technical to water containing a dispersant in sequence, and continuing stirring for a period of time to preliminarily disperse the technical in the water to form a coarse suspension;

[0011] S104, transferring the coarse suspension to a sand mill, and adding a set amount of grinding media; wherein the grinding media are glass beads or zirconium oxide beads;

[0012] S105, start the sand mill to perform grinding operation, and further refine the original drug particles through the collision and friction of the grinding medium to make the particle size reach a set range;

[0013] S106, transferring the ground suspension to a reactor, slowly adding 6 parts of alkylphenol polyoxyethylene ether emulsifier and 3 parts of ethylene glycol stabilizer under stirring, and continuing stirring for a set time to uniformly disperse the emulsifier and stabilizer in the suspension to form a stable emulsion system;

[0014] S107, in a stirring state, pre-make 0.5 parts of xanthan gum thickener into a paste with a set amount of water, then slowly add it to the reactor and stir evenly to make the viscosity of the suspension reach a preset range;

[0015] S108, adding 0.5 parts of an organosilicon defoamer to eliminate bubbles generated during the stirring process to obtain a difenoconazole-mystrobin suspension.

[0016] Furthermore, in step S105, the setting range of the particle size is: the average particle size is 1-5 microns.

[0017] Furthermore, in step S107, the preset range of viscosity is 500-1500 mPa·s.

[0018] Furthermore, in step S107, 0.5 parts of xanthan gum thickener is pre-made into a paste with 10-20 times the mass of water, and then added into the reactor.

[0019] The present invention also provides a method for preventing and controlling powdery mildew of Lanzhou white melon, based on the composite fungicide formula for preventing and controlling powdery mildew of Lanzhou white melon as described above, comprising:

[0020] S201. Before planting Lanzhou white melon, use difenoconazole-azoxystrobin suspension to disinfect the soil. Dilute the difenoconazole-azoxystrobin suspension to 500-800 times liquid, spray it evenly on the soil surface of the planting field, and then plow the field to fully mix the agent with the soil.

[0021] S202. For Lanzhou white melon seedlings, use 1000-1500 times dilution of difenoconazole-azoxystrobin suspension to soak or dip the seeds, then take them out and dry them before transplanting;

[0022] S203. When the Lanzhou white melon shows signs of powdery mildew, dilute the difenoconazole-pyraclostrobin suspension to 1500-2000 times liquid, and use a backpack sprayer or a motorized sprayer to evenly spray the whole plant, focusing on the front and back sides of the leaves, stems and vines, etc., spray once every 7-10 days, and spray continuously 2-3 times;

[0023] S204. If the powdery mildew of Lanzhou white melon is serious, adjust the dilution multiple of difenoconazole-pyraclostrobin suspension to 1000-1500 times, and shorten the spraying interval to spray once every 5-7 days for 3-4 times in a row;

[0024] S205. During the seedling stage of Lanzhou white melon, the safe interval of difenoconazole·myclobutanil suspension is 10-14 days; during the vine extension period, flowering and fruit setting period and fruit expansion period of Lanzhou white melon, the safe interval of difenoconazole·myclobutanil suspension is 7-10 days; during the fruit ripening period of Lanzhou white melon, the safe interval of difenoconazole·myclobutanil suspension is more than 14 days.

[0025] Furthermore, in step S202, the soaking time is 15-20 minutes, and the root dipping requires soaking the roots of the seedlings in the difenoconazole-mystrobin suspension for 3-5 minutes.

[0026] Furthermore, in step S203, in the early growth stage of the white melon, the amount of liquid medicine used per mu is controlled at 30±2 liters; in the middle and late growth stages, the amount of liquid medicine used per mu is increased to 40-50 liters.

[0027] The beneficial effects of the present invention are:

[0028] 1. The present invention prepares a difenoconazole-azoxystrobin suspension formulation, wherein difenoconazole has a good control effect on a variety of higher fungal diseases such as powdery mildew, anthracnose, leaf spot, etc., and azoxystrobin has good activity on almost all fungal diseases such as downy mildew and blight. After the two are compounded, the fungicidal spectrum is expanded, and the various fungal diseases that may be encountered during the growth of Lanzhou white melon can be effectively controlled, providing more comprehensive protection for plant growth. After difenoconazole and azoxystrobin are compounded, they have a synergistic effect on the fungicidal effect. The control effect of the compounded agent is better than the simple addition of the effects when the two are used alone, and a better control effect can be achieved with a lower dosage, which reduces the use cost of pesticides and also reduces pollution to the environment.

[0029] 2. The present invention performs soil treatment and seedling treatment before planting, prevents infection of pathogens from the source, and reduces the possibility of disease during the growth of white melon. Spraying and other prevention and control measures are taken in time according to the condition at different growth stages, forming a complete set of comprehensive prevention and control system, which can effectively control the occurrence and spread of diseases such as powdery mildew and ensure the healthy growth of white melon. According to the different growth stages of white melon and the degree of disease occurrence, the formula concentration, number of applications and dosage of difenoconazole-myclobutanil suspension are reasonably adjusted to achieve precise application of medicine. It can ensure the prevention and control effect, avoid blind use of medicine and excessive use of medicine, reduce the cost of pesticides, and reduce the adverse effects of pesticides on the environment and plants. While effectively preventing and controlling diseases, it reduces the use of highly toxic and high-residue pesticides, and reduces the pollution of pesticides to soil, water and air. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a flow chart of the method for preventing and controlling powdery mildew of Lanzhou white melon.

[0031] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0032] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0033] The invention provides a compound fungicide formula for preventing and controlling powdery mildew of Lanzhou white melon, comprising 10-20 parts of difenoconazole technical, 10-20 parts of azoxystrobin technical, 50-70 parts of solvent, 3-8 parts of emulsifier, 3-8 parts of dispersant, 2-5 parts of stabilizer, 0.2-0.8 parts of thickener and 0.1-0.5 parts of defoamer, to prepare a difenoconazole-azoxystrobin suspension with a total amount of 100 parts.

[0034] Wherein, the solvent is deionized water, the emulsifier is alkylphenol polyoxyethylene ether, the dispersant is lignin sulfonate, the stabilizer is ethylene glycol, the thickener is xanthan gum, and the defoamer is an organosilicon defoamer.

[0035] Solvents generally account for about 50%-70% of the total amount of the preparation, and their main function is to dissolve and disperse other ingredients. The amount of emulsifier usually accounts for 3%-8% of the total amount of the preparation, helping the active ingredients to be evenly dispersed in the water to form a stable suspension. Dispersants generally account for 3%-8%, which can prevent suspended particles from aggregating and precipitating, and maintain the stability of the system. The amount of stabilizer added is about 2%-5% of the total amount of the preparation, which can prevent the degradation of the active ingredients and improve the stability of the product during storage. The amount of thickener is usually 0.2%-0.8%, which is used to adjust the viscosity of the product so that the suspension has suitable fluidity and adhesion.

[0036] Specifically, the preparation steps of the difenoconazole-azoxystrobin suspension are as follows:

[0037] S101, and weigh 6 parts of alkylphenol polyoxyethylene ether, 5 parts of lignin sulfonate, 3 parts of ethylene glycol, 0.5 parts of xanthan gum and 0.5 parts of silicone defoamer to prepare the set mass; conduct quality inspection to ensure that there are no impurities and deterioration.

[0038] S102, weigh 15 parts of difenoconazole technical drug and 15 parts of azoxystrobin technical drug of set purity and quality, and ensure that the purity and quality of the technical drugs meet the requirements. Add 55 parts of deionized water into a container with a stirring device, start stirring, slowly add 5 parts of lignin sulfonate dispersant, stir evenly, and fully dissolve it in water;

[0039] S103, adding difenoconazole technical and azoxystrobin technical to water containing a dispersant in sequence, and continuing stirring for a period of time to preliminarily disperse the technical in the water to form a coarse suspension;

[0040] S104, transferring the coarse suspension to a sand mill, and adding a set amount of grinding media; wherein the grinding media are glass beads or zirconium oxide beads;

[0041] S105, start the sand mill and perform grinding operation. Through the collision and friction of the grinding medium, the original drug particles are further refined so that the particle size reaches the set range; wherein the setting range of the particle size is: the average particle size is 1-5 microns. During the grinding process, attention should be paid to controlling the parameters such as grinding time, temperature and speed to avoid affecting the product quality due to excessive temperature or excessive grinding.

[0042] S106, transferring the ground suspension to a reactor, slowly adding 6 parts of alkylphenol polyoxyethylene ether emulsifier and 3 parts of ethylene glycol stabilizer under stirring, and continuing stirring for a set time to uniformly disperse the emulsifier and stabilizer in the suspension to form a stable emulsion system;

[0043] S107. Under stirring, 0.5 parts of xanthan gum thickener are pre-made into a paste with a set amount of water (0.5 parts of xanthan gum thickener are pre-made into a paste with 10-20 times the mass of water), and then slowly added into the reactor and stirred evenly to make the viscosity of the suspension reach a preset range; wherein the preset range of viscosity is: between 500-1500 mPa·s.

[0044] S108, adding 0.5 parts of an organosilicon defoamer to eliminate bubbles generated during the stirring process, and obtaining a difenoconazole-azoxystrobin suspension. Finally, the obtained difenoconazole-azoxystrobin suspension is subjected to quality inspection, including inspection of indicators such as active ingredient content, particle size distribution, suspension rate, stability, and pH value, to ensure that the quality meets relevant standards and requirements.

[0045] like Figure 1 As shown, the present invention also provides a method for preventing and controlling powdery mildew of Lanzhou white melon, based on the compound fungicide formula for preventing and controlling powdery mildew of Lanzhou white melon as described above, comprising:

[0046] S201. Before planting Lanzhou white melon, use fenpropimorph suspension to disinfect the soil. Dilute the fenpropimorph suspension into 500-800 times liquid, spray it evenly on the soil surface of the planting field, and then plow the field to fully mix the agent with the soil; this can effectively kill the pathogen spores in the soil and reduce the initial infection source.

[0047] S202. For Lanzhou white melon seedlings, use 1000-1500 times diluted dimethoate of fenpropimorph·myclobutanil suspension for seed soaking or root dipping for 15-20 minutes. For root dipping, soak the roots of the seedlings in the dimethoate·myclobutanil suspension for 3-5 minutes, then take out and dry them before transplanting. This can prevent the seedlings from carrying pathogens and improve the disease resistance of the seedlings.

[0048] S203. When the Lanzhou white melon shows signs of powdery mildew, dilute the fenpropimorph·pyraclostrobin suspension to 1500-2000 times, use a backpack sprayer or motorized sprayer to spray the whole plant evenly, focusing on the front and back sides of the leaves, stems and vines, etc., spray once every 7-10 days, and spray continuously for 2-3 times. Adjust the dosage according to the growth stage and planting density of the white melon. Generally, the dosage per mu is 30-50 liters. In the early growth stage of the white melon, the plants are small, and the dosage per mu is controlled at 30±2 liters; in the middle and late growth stages, the plants are large and dense, and the dosage per mu is increased to 40-50 liters.

[0049] S204. If the powdery mildew of Lanzhou white melon is serious, adjust the dilution ratio of difenoconazole-pyraclostrobin suspension to 1000-1500 times, and shorten the spraying interval, spray once every 5-7 days, and spray continuously for 3-4 times; while spraying the pesticide, you can combine manual removal of diseased leaves and vines, take the diseased remains out of the field and destroy them in a centralized manner to reduce the re-transmission and infection of the pathogen. In addition, pay attention to strengthening field ventilation and light transmission, reducing humidity, and creating environmental conditions that are not conducive to the occurrence of powdery mildew.

[0050] The safe intervals of S205 and difenoconazole-azoxystrobin suspension in different growth stages of Lanzhou white melon are generally as follows:

[0051] Seedling stage: The safety interval is relatively long, usually 10-14 days. At this time, the honey melon seedlings are relatively fragile, and their growth and metabolism are relatively slow. It takes a certain amount of time for the pesticide to remain and dissipate in the plant. In order to avoid the adverse effects of pesticide residues on seedling growth and ensure the safety of subsequent growth, a longer safety interval is required.

[0052] Vine extension period: The safe interval is generally 7-10 days. As the white melon plant grows, its ability to metabolize the pesticide is enhanced, but it still takes a certain amount of time to degrade and eliminate the pesticide residue. The 7-10 day interval can effectively prevent and control diseases while reducing the risk of pesticide residue.

[0053] Flowering and fruiting period: The safe interval is generally 7-10 days. This stage is a critical period for the growth of honeysuckle, which is more sensitive to pesticides. At the same time, in order to ensure the quality and safety of the fruit, it is necessary to strictly control the use of pesticides and the safe interval to prevent the pesticides from having adverse effects on flowers and young fruits.

[0054] Fruit expansion period: The safety interval is generally 7-10 days. The fruit begins to expand rapidly, and the control of pesticide residues is required to be high. The 7-10-day safety interval helps to ensure that the pesticide residues in the fruit are within a safe range, ensuring the quality of the fruit and edible safety.

[0055] Fruit maturity: When the harvest is approaching, the safety interval should be extended to more than 14 days. In the period before the fruit matures, the use of pesticides should be strictly controlled to ensure that the pesticide residues in the fruit meet the food safety standards when it is harvested.

[0056] The invention prepares a difenoconazole-azoxystrobin suspension formula, wherein difenoconazole has a good control effect on a variety of higher fungal diseases such as powdery mildew, anthracnose, leaf spot, etc., and azoxystrobin has good activity on almost all fungal diseases such as downy mildew and blight. After the two are compounded, the fungicidal spectrum is expanded, and a variety of fungal diseases that may be encountered during the growth of Lanzhou white melon can be effectively controlled, providing more comprehensive protection for plant growth. After difenoconazole and azoxystrobin are compounded, they have a synergistic effect on the fungicidal effect. The control effect of the compounded agent is better than the simple addition of the effects of the two when used alone, and a better control effect can be achieved with a lower dosage, thereby reducing the use cost of pesticides and also reducing pollution to the environment.

[0057] The present invention performs soil treatment and seedling treatment before planting, prevents infection of pathogens from the source, and reduces the possibility of disease during the growth of honeydew melon. Spraying and other prevention and control measures are taken in time according to the condition of the disease at different growth stages, forming a complete set of comprehensive prevention and control system, which can effectively control the occurrence and spread of diseases such as powdery mildew and ensure the healthy growth of honeydew melon. According to the different growth stages of honeydew melon and the degree of disease occurrence, the formula concentration, application times and dosage of difenoconazole-myclobutanil suspension are reasonably adjusted to achieve precise application of medicine. It can ensure the prevention and control effect, avoid blind use of medicine and excessive use of medicine, reduce the cost of pesticides, and reduce the adverse effects of pesticides on the environment and plants. While effectively preventing and controlling diseases, it reduces the use of highly toxic and high-residue pesticides and reduces the pollution of pesticides to soil, water and air.

[0058] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, device, article or method including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, device, article or method. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, device, article or method including the element.

[0059] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A compound fungicide formula for preventing and treating powdery mildew of Lanzhou white melon, characterized in that: The invention comprises 10 to 20 parts of difenoconazole technical, 10 to 20 parts of azoxystrobin technical, 50 to 70 parts of solvent, 3 to 8 parts of emulsifier, 3 to 8 parts of dispersant, 2 to 5 parts of stabilizer, 0.2 to 0.8 parts of thickener and 0.1 to 0.5 parts of defoamer, so as to prepare a difenoconazole-azoxystrobin suspension with a total amount of 100 parts.

2. The compound fungicide formula for preventing and treating powdery mildew of Lanzhou white melon according to claim 1, characterized in that: The solvent is deionized water, the emulsifier is alkylphenol polyoxyethylene ether, the dispersant is lignin sulfonate, the stabilizer is ethylene glycol, the thickener is xanthan gum, and the defoamer is an organosilicon defoamer.

3. The compound fungicide formula for preventing and treating powdery mildew of Lanzhou white melon according to claim 2, characterized in that: The preparation steps of the difenoconazole-azoxystrobin suspension are as follows: S101, and weighing 6 parts of alkylphenol polyoxyethylene ether, 5 parts of lignin sulfonate, 3 parts of ethylene glycol, 0.5 parts of xanthan gum and 0.5 parts of silicone defoamer; S102, weighing 15 parts of difenoconazole technical drug and 15 parts of azoxystrobin technical drug of set purity and mass, adding 55 parts of deionized water in a container with a stirring device, turning on the stirring, slowly adding 5 parts of lignin sulfonate dispersant weighed, stirring evenly, and fully dissolving them in the water; S103, adding difenoconazole technical and azoxystrobin technical to water containing a dispersant in sequence, and continuing stirring for a period of time to preliminarily disperse the technical in the water to form a coarse suspension; S104, transferring the coarse suspension to a sand mill, and adding a set amount of grinding media; wherein the grinding media are glass beads or zirconium oxide beads; S105, turning on the sand mill to perform a grinding operation, and further refining the original drug particles through the collision and friction of the grinding medium to make the particle size reach a set range; S106, transferring the ground suspension to a reactor, slowly adding 6 parts of alkylphenol polyoxyethylene ether emulsifier and 3 parts of ethylene glycol stabilizer under stirring, and continuing stirring for a set time to uniformly disperse the emulsifier and stabilizer in the suspension to form a stable emulsion system; S107, in a stirring state, pre-make 0.5 parts of xanthan gum thickener into a paste with a set amount of water, then slowly add it to the reactor and stir evenly to make the viscosity of the suspension reach a preset range; S108, adding 0.5 parts of an organosilicon defoamer to eliminate bubbles generated during the stirring process to obtain a difenoconazole-mystrobin suspension.

4. The compound fungicide formula for preventing and treating powdery mildew of Lanzhou white melon according to claim 3, characterized in that: In step S105, the setting range of the particle size is: the average particle size is 1-5 microns.

5. The compound fungicide formula for preventing and treating powdery mildew of Lanzhou white melon according to claim 3, characterized in that: In the step S107, the preset range of viscosity is 500-1500 mPa·s.

6. The compound fungicide formula for preventing and treating powdery mildew of Lanzhou white melon according to claim 3, characterized in that: In the step S107, 0.5 parts of xanthan gum thickener is pre-made into a paste with 10-20 times the mass of water, and then added into the reaction kettle.

7. A method for preventing and controlling powdery mildew of Lanzhou white melon, characterized in that: The compound fungicide formula for preventing and controlling powdery mildew of Lanzhou white melon according to any one of claims 1 to 6 comprises: S201. Before planting Lanzhou white melon, use difenoconazole-azoxystrobin suspension to disinfect the soil. Dilute the difenoconazole-azoxystrobin suspension to 500-800 times liquid, spray it evenly on the soil surface of the planting field, and then plow the field to fully mix the agent with the soil. S202. For Lanzhou white melon seedlings, use 1000-1500 times dilution of difenoconazole-azoxystrobin suspension to soak or dip the seeds, then take them out and dry them before transplanting; S203. When the Lanzhou white melon shows signs of powdery mildew, dilute the difenoconazole-pyraclostrobin suspension to 1500-2000 times liquid, and use a backpack sprayer or a motorized sprayer to evenly spray the whole plant, focusing on the front and back sides of the leaves, stems and vines, etc., spray once every 7-10 days, and spray continuously 2-3 times; S204. If the powdery mildew of Lanzhou white melon is serious, adjust the dilution multiple of difenoconazole-pyraclostrobin suspension to 1000-1500 times, and shorten the spraying interval to spray once every 5-7 days for 3-4 times in a row; S205. During the seedling stage of Lanzhou white melon, the safe interval of difenoconazole·myclobutanil suspension is 10-14 days; during the vine extension period, flowering and fruit setting period and fruit expansion period of Lanzhou white melon, the safe interval of difenoconazole·myclobutanil suspension is 7-10 days; during the fruit ripening period of Lanzhou white melon, the safe interval of difenoconazole·myclobutanil suspension is more than 14 days.

8. The method for preventing and controlling powdery mildew of Lanzhou white melon according to claim 1, characterized in that: In step S202, the soaking time is 15-20 minutes, and the root dipping requires soaking the roots of the seedlings in the difenoconazole-pyraclostrobin suspension for 3-5 minutes.

9. The method for preventing and controlling powdery mildew of Lanzhou white melon according to claim 1, characterized in that: In step S203, in the early growth stage of the white melon, the amount of liquid medicine used per mu is controlled at 30±2 liters; in the middle and late growth stages, the amount of liquid medicine used per mu is increased to 40-50 liters.

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