Application of a plant-derived pesticide of ar-turmerone in prevention and treatment of cucumber downy mildew

Abstract

The application belongs to the technical field of biological pesticides, and specifically provides application of an ar-turmerone pharmaceutical composition in prevention and treatment of cucumber downy mildew, wherein the ar-turmerone pharmaceutical composition contains 4.9-8.1% ar-turmerone in terms of mass percentage. It has been proved that, after the ar-turmerone pesticide is prepared into an emulsifiable concentrate, the emulsifiable concentrate is diluted by 150-600 times, and the diluted emulsifiable concentrate is used for 2-3 times of continuous spraying with an interval of 5-7 days from the initial stage of cucumber downy mildew, the prevention and treatment effect of the ar-turmerone pharmaceutical composition on cucumber downy mildew is significantly higher than that of a control chemical pesticide. Meanwhile, the ar-turmerone pharmaceutical composition belongs to a low-toxicity grade, is easy to hydrolyze in the environment and easy to degrade in the soil, and the crops grow normally. In addition, the ar-turmerone pharmaceutical composition has no adverse effect on non-target organisms.

Description

Technical Field

[0001] This invention belongs to the field of biopesticide technology, and in particular relates to the application of a plant-derived aromatic curcumin pesticide in the control of cucumber downy mildew. Background Technology

[0002] Downy mildew is a common fungal disease of cucumber, caused by *Pseudoperonospora cubensis*, which severely affects cucumber yield and quality. Besides cucumber, this pathogen can infect 50 species across 20 genera in the Cucurbitaceae family under natural conditions. Downy mildew primarily affects cucumber leaves, causing irregular, water-soaked lesions to appear on the leaf margins and undersides. These lesions gradually enlarge, and a grayish-black mold layer develops on the undersides of leaves under high humidity. In severe cases, multiple lesions merge into larger lesions, causing leaves to wither and curl, eventually leading to the death of the entire plant, significantly impacting cucumber yield and quality.

[0003] The control methods for cucumber downy mildew mainly rely on agricultural and chemical control. Firstly, select disease-resistant varieties, soak seeds to promote germination, and cultivate strong seedlings; select healthy, disease-free seedlings, strengthen cultivation management, and apply fertilizer scientifically; finally, combine with chemical agents for control (Liu Jingdong. A Brief Analysis of Cucumber Downy Mildew Control Methods [J]. Farmers' Friend for Prosperity, 2018, No. 17: 143). Chemical control is low-cost and fast-acting, but long-term use of chemical pesticides can increase pathogen resistance, leading to increased pesticide dosage, excessive pesticide residues in agricultural products, and environmental pollution, endangering human health. Therefore, the control of cucumber downy mildew urgently requires highly efficient, low-toxicity, and environmentally friendly biological pesticides.

[0004] Biopesticides are pesticide formulations that use living organisms or their metabolites that can control pests, pathogens, weeds, nematodes, rodents, and other harmful organisms, or substances with specific effects synthesized through biomimicry, as their active ingredients. Their active ingredients mainly originate from three sources: animals, plants, and microorganisms. Currently, there are 34 registered biopesticides for controlling cucumber downy mildew, with 12 active ingredients, including allicin, osthol, berberine, chitosan, Trichoderma, and Bacillus subtilis. With the acceleration of national green food certification and the increasing public demand for agricultural product safety, the demand for biopesticides is constantly rising.

[0005] Chinese invention patent application CN108935465A discloses the application of a bisabolane-type semiterpenoid compound in the control of powdery mildew, but so far there have been no reports of its application in the control of cucumber downy mildew. Summary of the Invention

[0006] The inventors conducted research on plant-derived pesticides for the control of cucumber downy mildew and discovered that treatment with approximately 6.5% curcumin emulsifiable concentrate diluted 300 times had excellent control effects on cucumber downy mildew, thus completing this invention.

[0007] Therefore, the present invention provides an application of an aromatic curcuminone pharmaceutical composition in the control of cucumber downy mildew, wherein the aromatic curcuminone pharmaceutical composition contains 4.9-8.1% aromatic curcuminone by weight. Preferably, the aromatic curcuminone pharmaceutical composition contains 6.5% aromatic curcuminone, which can achieve good control of cucumber downy mildew.

[0008] The structural formula of the compound aromatic curcumin is as follows: Figure 1 As shown. Aromatic curcuminones can be extracted from turmeric plants. For details on the extraction, separation, purification, and identification of aromatic curcuminones, please refer to the following literature:

[0009] WJ Fu, J Liu, MZ hang, JQ Li, JF Hu, LR Xu, GH Dai (2018). Isolation, purification and identification of the active compound of turmeric and its potential application to control cucumber powdery mildew. The Journal of Agricultural Science 156, 358-366.

[0010] In a preferred embodiment, the aromatic curcumin pharmaceutical composition is an emulsifiable concentrate preparation. Specifically, the aromatic curcumin emulsifiable concentrate comprises, by weight percentage, 30-70% aromatic curcumin parent material, 10-35% emulsifier, and 15-50% solvent.

[0011] The aromatic curcumin mother drug is prepared by the following method: Curcuma rhizome raw material is dried and pulverized, then extracted with an ethanol-water solution to obtain an extract; the extract is concentrated and then extracted with an organic solvent to obtain an aqueous phase product and an oil phase product; the oil phase product is subjected to molecular distillation to obtain the aromatic curcumin mother drug. Preferably, the aromatic curcumin mother drug contains 9.75-16.25% by mass of the compound aromatic curcumin. Further, in addition to the compound aromatic curcumin, the aromatic curcumin mother drug also contains curcuminone, gingerol, and other components, which can alleviate the development of drug resistance in the target; at the same time, the agent has low toxicity and is low-toxicity to terrestrial organisms in the environment, including bees, silkworms, and birds.

[0012] In a preferred embodiment, the mass percentage of the aromatic curcumin drug composition can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, etc.; the mass percentage of the emulsifier can be 10%, 15%, 20%, 25%, 30%, 35%, etc.; and the mass percentage of the solvent can be 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc. Specific values ​​within the above ranges can be selected, and will not be elaborated further here.

[0013] In a preferred embodiment, the aromatic curcumin emulsifiable concentrate comprises, by weight percentage, 40-60% aromatic curcumin raw material, 20-30% emulsifier, and 15-35% solvent. When the aromatic curcumin raw material, emulsifier, and solvent are combined in the above-mentioned more preferred weight ratio, the product exhibits superior high-temperature, low-temperature, and room-temperature stability, enabling the agent to exert its efficacy in controlling cucumber downy mildew more stably and for a longer period.

[0014] In a preferred embodiment, the solvent is selected from any one or a combination of at least two of methyl oleate, soybean oil, corn oil, rapeseed oil, or pine oil. By using the above-mentioned biodegradable and environmentally friendly solvents with low pollution, environmental pollution is reduced, which is more beneficial to the application of this emulsifiable concentrate formulation.

[0015] In some embodiments, the emulsifier is selected from nonionic and anionic emulsifiers. Preferably, the nonionic emulsifier includes any one or a combination of at least two of styrene phenol polyoxyethylene ether, sorbitan trioleate polyoxyethylene ether, styrene phenol-ethoxy-propoxylate, or castor oil polyglycol ether ester. The anionic emulsifier is selected from any one or a combination of at least two of diphenyl sulfonate, α-olefin sulfonate, lignin sulfonate, ethoxylated alkylphenol sulfonate, alkoxylated arylphenol sulfonate, condensed naphthalene sulfonate, dodecylbenzene or tridecylbenzene sulfonate, naphthalene or alkylnaphthalene sulfonate, or sulfosuccinate.

[0016] This invention optimizes the emulsifier formulation to better coordinate with the solvent and aromatic curcumin precursor, thereby making the system more stable and ensuring a sustained and stable efficacy.

[0017] In some preferred embodiments, the emulsifier comprises, by weight percentage, 30-40% styrene phenol polyoxyethylene ether, 30-40% sorbitan trioleate polyoxyethylene ether, and 25-35% calcium dodecylbenzene sulfonate. The weight percentage of styrene phenol polyoxyethylene ether can be selected from 30%, 32%, 33%, 35%, 36%, 38%, 40%, etc.; the weight percentage of sorbitan trioleate polyoxyethylene ether can be selected from 30%, 32%, 33%, 35%, 36%, 38%, 40%, etc.; and the weight percentage of calcium dodecylbenzene sulfonate can be selected from 25%, 27%, 28%, 30%, 32%, 35%, 40%, etc. Specific values ​​within the above ranges are all selectable and will not be elaborated further here. Through optimized selection of solvent and emulsifier types, this emulsifiable concentrate formulation is low in toxicity, safe, environmentally friendly, has good stability, good emulsifying performance, and excellent residual effect.

[0018] In a preferred embodiment, the application includes applying the aromatic curcumin pharmaceutical composition of the present invention diluted 150-600 times to cucumber plants, preferably 150-300 times, more preferably 300 times.

[0019] In a preferred embodiment, the application includes starting at the early stage of cucumber downy mildew, applying the medicine 2-3 times consecutively, with an interval of 5-7 days between each application.

[0020] Technical effect

[0021] This invention marks the first use of aromatic curcumin, a plant-derived pesticide, for the control of cucumber downy mildew. The active ingredient in this pesticide, aromatic curcumin, reduces the spore germination rate of the pathogen and ruptures the cell walls of already germinated spores and hyphae, achieving an inhibitory effect. Aromatic curcumin acts on plants, causing plant cells to produce more phenolic and flavonoid substances, thus enhancing plant immunity. It has been demonstrated that a 150-fold dilution of 6.5% aromatic curcumin emulsifiable concentrate significantly increased the control efficacy compared to the control chemical agent, while a 300-fold dilution of the tested agent showed no significant difference in control efficacy compared to the control chemical agent. Experimental results demonstrate that 4.9-8.1%, especially the 6.5% aromatic curcumin emulsifiable concentrate, is significantly effective in controlling cucumber downy mildew.

[0022] This invention relates to a plant-derived pesticide containing a mixture of aromatic curcumin, turmeric, gingerols, and other compounds, which can alleviate the development of drug resistance in target organisms. Simultaneously, the pesticide is of low toxicity and has low toxicity to terrestrial organisms, including bees, silkworms, and birds. The main component of the aromatic curcumin emulsifiable concentrate, aromatic curcumin, and other components are derived from the natural plant turmeric, which is permitted for use as a food additive in both my country and the United States and does not contain any toxic or harmful substances. Furthermore, it is easily hydrolyzed in the environment and readily degraded in soil, thus preventing long-term environmental accumulation and degradation. Experiments have shown that treatments with 4.9-8.1%, especially 6.5%, of aromatic curcumin emulsifiable concentrate have no phytotoxicity on cucumbers, resulting in normal crop growth; and have no adverse effects on non-target organisms.

[0023] A novel emulsifiable concentrate formulation for controlling cucumber downy mildew was prepared by using a specific mass ratio of aromatic curcumin mother drug, emulsifier, and solvent. The preparation process is simple and convenient, and it has excellent high and low temperature stability, which enables the agent to exert its control effect on cucumber downy mildew more stably and for a longer period of time. Attached Figure Description

[0024] Figure 1 The structural formula of the compound aromatic curcumin;

[0025] Figure 2 The invention presents a comparison of leaf disease incidence in different treatments of cucumber downy mildew controlled by aromatic curcumin emulsifiable concentrate in an embodiment of the invention. Detailed Implementation

[0026] The preferred embodiments of the present invention are described below to make the technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0027] The following experiment, based on the above-mentioned aromatic curcumin plant-derived pesticide of the present invention, verifies its application in the prevention and control of cucumber downy mildew.

[0028] Preparation Example 1

[0029] Preparation of aromatic curcumin mother liquor: Dried turmeric rhizome raw material was pulverized and extracted with 75% ethanol aqueous solution at 20℃ for 48 h to obtain an extract. The extract was concentrated and extracted with vegetable oil to obtain an aqueous phase product and an oil phase product. The oil phase product was subjected to molecular distillation at 3 Pa and 120℃ to obtain aromatic curcumin mother liquor. The content of aromatic curcumin in the aromatic curcumin mother liquor was determined by high performance liquid chromatography (using methanol and water as the mobile phase, a C18 (4.6 mm × 250 mm, 5 μm) column, and ultraviolet light at 242 nm).

[0030] Preparation of aromatic turmeric emulsifiable concentrate: 38% aromatic turmeric raw material, 30% emulsifier (composed of 35% tristyrene phenol polyoxyethylene ether, 35% sorbitan trioleate polyoxyethylene ether and 30% calcium dodecylbenzene sulfonate), and 32% corn oil were mixed and stirred at high speed to prepare 5.2% aromatic turmeric emulsifiable concentrate.

[0031] Preparation Example 2

[0032] Preparation of aromatic turmeric emulsifiable concentrate: 50% aromatic turmeric raw material, 25% emulsifier (composed of 35% tristyrene phenol polyoxyethylene ether, 35% sorbitan trioleate polyoxyethylene ether and 30% calcium dodecylbenzene sulfonate), and 25% methyl oleate were mixed and stirred at high speed to prepare 6.5% aromatic turmeric emulsifiable concentrate.

[0033] Preparation Example 3

[0034] Preparation of aromatic turmeric emulsifiable concentrate: 62.3% aromatic turmeric raw material, 22.7% emulsifier (composed of 35% tristyrene phenol polyoxyethylene ether, 35% sorbitan trioleate polyoxyethylene ether and 30% calcium dodecylbenzene sulfonate), and 15% soybean oil were mixed and stirred at high speed to prepare 8.1% aromatic turmeric emulsifiable concentrate.

[0035] Example 1

[0036] In accordance with GB / T 17980.26-2000 Guidelines for Field Efficacy Testing of Pesticides (I) – Control of Cucumber Downy Mildew with Fungicides, a field test was conducted on the control of cucumber downy mildew using aromatic curcumin emulsifiable concentrate.

[0037] Specifically as follows:

[0038] 1. Test conditions

[0039] 1.1 Experimental Materials

[0040] Test reagent: The aromatic curcumin emulsifiable concentrate prepared in Example 2 was provided by the Plant Health and Natural Products Laboratory of the School of Agriculture and Biology, Shanghai Jiao Tong University.

[0041] Control agent: 687.5 g / L fluopyram·cymoxanil suspension (Silver Farid), Bayer Crop Science (China) Co., Ltd.

[0042] Experiment period: September 30, 2022 - November 3, 2022.

[0043] Experiment location: Xujiacao Vegetable Base, Xinbang Town, Songjiang District, Shanghai.

[0044] Cucumber variety: Nakata Yanqing, a susceptible variety.

[0045] 1.2 Experimental Apparatus

[0046] The Shandong Weishi 3WJD-18 electrostatic sprayer features a cone-shaped nozzle and a spray flow rate of 0.95 liters per minute during application.

[0047] 2. Test Methods

[0048] The local soil is clay loam with moderate organic matter content and a pH of 6.3. Before cucumber sowing, 50 kg / mu of compound fertilizer was applied, and conventional local management practices were followed. During the experiment, the cucumbers grew well. 10% flonicamid water-dispersible granules were used to control aphids, and 60 g / L spinosad suspension concentrate (Ailushi) was used to control thrips and melon borers. The experiment consisted of 5 treatments (Table 1), with 3 replicates, for a total of 15 plots, each plot measuring 18 m². 2 The plots were randomly arranged by area group. The first applications of pesticide were on October 13, 2022, and June 25, 2023, respectively, during the cucumber's 6-8 leaf stage and the early stage of downy mildew. The pesticide was applied evenly by spraying, using 750 liters of water per hectare. Each application was spaced 7 days apart, and three consecutive applications were made.

[0049] Table 1 Experimental Design for Controlling Downy Mildew with Test Agents

[0050]

[0051] 2.2 Survey Methods

[0052] Seven days after the second and third applications of the medication, an efficacy survey was conducted. Four points were checked in each plot, with two plants checked at each point. All leaves of each plant were checked to investigate the disease status and severity on each leaf.

[0053] Classification method for leaf downy mildew disease:

[0054] Grade 0: No lesions;

[0055] Grade 1: The lesion area accounts for less than 5% of the total leaf area;

[0056] Grade 3: The lesion area accounts for 6% to 10% of the total leaf area;

[0057] Level 5: The lesion area accounts for 11% to 25% of the total leaf area;

[0058] Level 7: Lesions cover 26% to 50% of the total leaf area;

[0059] Level 9: The lesion area accounts for more than 50% of the total leaf area.

[0060] 2.3 Method for Calculating Drug Efficacy

[0061] Disease index (leaf) = [∑(number of diseased leaves at each level × relative level value) / (total number of leaves surveyed × 9)] × 100

[0062] Control efficacy (%) = (Disease index after application in the blank control area - Disease index after application in the treated area) / Disease index after application in the blank control area × 100

[0063] The differences in efficacy among the treatment areas were compared using Duncan's multiple range test (DMRT) to statistically analyze the experimental data, and significance tests were performed using p = 0.05 and 0.01 (SPSS 17.0).

[0064] 2.4 Direct impact on crops

[0065] During each efficacy study, the effects of the tested pesticide on cucumber plants were observed.

[0066] 3. Experimental Results

[0067] 3.1 Field efficacy trial results of curcumin emulsifiable concentrate for controlling cucumber downy mildew

[0068] Seven days after the second application of the drug in 2022, the disease index of the control group (water) was 41.76, while the disease indices of the 150, 300, and 600-fold dilutions of the tested drug were 10.00, 11.67, and 14.72, respectively, demonstrating the effectiveness of the tested drug in controlling cucumber downy mildew. The control efficacy of the 150, 300, and 600-fold dilutions was 76.16%, 72.18%, and 64.90%, respectively. There was no significant difference in control efficacy between the 150-fold and 300-fold dilutions and the control drug (76.37%) (p < 0.01). Seven days after the third application of the drug, the disease index of the control group (water) was 69.26. The disease indices of the treatment groups (150, 300, and 600 times dilution of the tested drug) were 16.48, 19.35, and 25.37, respectively, with control effects of 76.20%, 72.06%, and 63.37%. There was no significant difference in control efficacy between the 150-fold and 300-fold dilutions and the control drug (75.67%) (p < 0.01).

[0069] Table 2. Results of field efficacy experiments of the tested pesticides for controlling cucumber downy mildew (November 2022)

[0070]

[0071] Different capital letters after the data in the same column indicate a significant difference at p < 0.05, while different lowercase letters indicate a significant difference at p < 0.01.

[0072] 3.2 Safety of the test agent to cucumber plants

[0073] All treatments with the tested pesticides showed no phytotoxicity to cucumbers, and the crops grew normally, with no adverse effects on non-target organisms.

[0074] Example 2

[0075] In accordance with GB / T 17980.26-2000 Guidelines for Field Efficacy Testing of Pesticides (I) – Control of Cucumber Downy Mildew with Fungicides, a field test was conducted on the control of cucumber downy mildew using aromatic curcumin emulsifiable concentrate.

[0076] Specifically as follows:

[0077] 1. Test conditions

[0078] 1.1 Experimental Materials

[0079] Test reagent: The aromatic curcumin emulsifiable concentrate prepared in Example 2 was provided by the Plant Health and Natural Products Laboratory of the School of Agriculture and Biology, Shanghai Jiao Tong University.

[0080] Control agent: 687.5 g / L fluopyram·cymoxanil suspension (Silver Farid), Bayer Crop Science (China) Co., Ltd.

[0081] Experiment period: June 2, 2023 - July 12, 2023.

[0082] Experiment location: Xujiacao Vegetable Base, Xinbang Town, Songjiang District, Shanghai.

[0083] Cucumber variety: Nakata Yanqing, a susceptible variety.

[0084] 1.2 Experimental Apparatus

[0085] The Shandong Weishi 3WJD-18 electrostatic sprayer features a cone-shaped nozzle and a spray flow rate of 0.95 liters per minute during application.

[0086] 2. Test Methods

[0087] The local soil is clay loam with moderate organic matter content and a pH of 6.3. Before cucumber sowing, 50 kg / mu of compound fertilizer was applied, and conventional local management practices were followed. During the experiment, the cucumbers grew well. 10% flonicamid water-dispersible granules were used to control aphids, and 60 g / L spinosad suspension concentrate (Ailushi) was used to control thrips and melon borers. The experiment consisted of 5 treatments (Table 3), with 3 replicates, for a total of 15 plots, each plot measuring 18 m². 2 The plots were randomly arranged by area group. The first applications of pesticide were on October 13, 2022, and June 25, 2023, respectively, during the cucumber's 6-8 leaf stage, when downy mildew did not occur. The pesticide was applied evenly by spraying, using 750 liters of water per hectare. Each application was spaced 7 days apart, for a total of 3 applications.

[0088] Table 3 Experimental Design for Controlling Cucumber Downy Mildew with Test Agents Table 3 Experimental Design for Controlling Cucumber Downy Mildew with Test Agents

[0089]

[0090] 2.2 Survey Methods

[0091] Seven days after the second and third applications of the medication, an efficacy survey was conducted. Four points were checked in each plot, with two plants checked at each point. All leaves of each plant were checked to investigate the disease status and severity on each leaf.

[0092] Classification method for leaf downy mildew disease:

[0093] Grade 0: No lesions;

[0094] Grade 1: The lesion area accounts for less than 5% of the total leaf area;

[0095] Grade 3: The lesion area accounts for 6% to 10% of the total leaf area;

[0096] Level 5: The lesion area accounts for 11% to 25% of the total leaf area;

[0097] Level 7: Lesions cover 26% to 50% of the total leaf area;

[0098] Level 9: The lesion area accounts for more than 50% of the total leaf area.

[0099] 2.3 Method for Calculating Drug Efficacy

[0100] Disease index (leaf) = [∑(number of diseased leaves at each level × relative level value) / (total number of leaves surveyed × 9)] × 100

[0101] Control efficacy (%) = (Disease index after application in the blank control area - Disease index after application in the treated area) / Disease index after application in the blank control area × 100

[0102] The differences in efficacy among the treatment areas were compared using Duncan's multiple range test (DMRT) to statistically analyze the experimental data, and significance tests were performed using p = 0.05 and 0.01 (SPSS 17.0).

[0103] 2.4 Direct impact on crops

[0104] During each efficacy study, the effects of the tested pesticide on cucumber plants were observed.

[0105] 3. Test Results

[0106] 3.1 Results of field efficacy trials of turmeric flavonoids in controlling cucumber downy mildew

[0107] Field observation seven days after the third application of the pesticide in 2023 showed that the blank control group had a large number of lesions on the cucumber leaves; the cucumbers treated with 6.5% curcumin EC had milder disease, especially the group treated with 150 times diluted 6.5% curcumin EC had significantly fewer lesions on the leaves. Figure 2Visual observation indicates that 6.5% aromatic curcumin emulsifiable concentrate has a good preventive and therapeutic effect on the disease.

[0108] The disease index survey results 7 days after the second application of the test agent in 2023 showed that the disease index of the water control group was 8.25, while the disease indices of the 150, 300, and 600-fold dilutions of the test agent were 2.01, 2.32, and 2.68, respectively, further demonstrating the control effect of the test agent on cucumber downy mildew. The control effects of the 150, 300, and 600-fold dilutions of the test agent were 75.60%, 71.86%, and 67.57%, respectively (Table 4). The control effect of the 150-fold dilution was significantly higher than that of the 600-fold dilution, while the control effect of the 300-fold dilution was not significantly different from that of the 150-fold and 600-fold dilutions (p < 0.01). When the test agent was diluted 150 and 300 times, the control effect was not significantly different from that of the control group (73.41%) (p < 0.01). Seven days after the third application of the drug, the disease index of the control group (water) was 13.12. The disease indices of the groups treated with 150, 300, and 600 times dilution of the tested drug were 2.58, 3.28, and 4.18, respectively, with control effects of 80.33%, 75.03%, and 68.14%. The differences in control efficacy among the 150, 300, and 600 times dilutions of the tested drug were significant (p < 0.01). The control efficacy of the 150-fold dilution was significantly higher than that of the control drug, while the control efficacy of the 300-fold dilution was not significantly different from that of the control drug (p < 0.01).

[0109] Table 4. Results of field efficacy experiments of the tested pesticides for controlling cucumber downy mildew (July 2023)

[0110]

[0111] Different capital letters after the data in the same column indicate a significant difference at p < 0.05, while different lowercase letters indicate a significant difference at p < 0.01.

[0112] 3.2 Safety of the test agent to cucumber plants

[0113] All treatments with the tested pesticides showed no phytotoxicity to cucumbers, and the crops grew normally, with no adverse effects on non-target organisms.

[0114] 4 ratings

[0115] Two consecutive years of field trials have demonstrated that 6.5% curcumin emulsifiable concentrate is effective against cucumber downy mildew. After three applications (600x, 300x, and 150x dilution), the control efficacy against cucumber downy mildew was approximately 63%-80%, and the product is safe for crops. Recommended application: Dilute the formulation 300-150 times and apply evenly by spraying before or at the early stage of cucumber downy mildew occurrence. Apply once every 7 days, for 2-3 consecutive applications.

[0116] This invention has demonstrated that 6.5% aromatic curcumin emulsifiable concentrate has excellent control effects against cucumber downy mildew, and aromatic curcumin emulsifiable concentrates with aromatic curcumin content in the range of 4.9-8.1% can achieve similar effects. This indicates that the aromatic curcumin drug composition of this invention can control a variety of diseases in cucurbit crops and is a broad-spectrum, safe, and highly effective new plant-derived pesticide. In aromatic curcumin emulsifiable concentrates, if the aromatic curcumin content is too low, the purpose of controlling cucumber downy mildew cannot be achieved; while if the aromatic curcumin content is too high, it will greatly increase the purification cost of aromatic curcumin, thereby increasing the preparation cost of aromatic curcumin emulsifiable concentrates, which will limit the promotion of this biological pesticide.

[0117] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. The application of an aromatic curcuminone pharmaceutical composition in the control of cucumber downy mildew, wherein the aromatic curcuminone pharmaceutical composition comprises 4.9-8.1% of aromatic curcuminone by mass percentage; the aromatic curcuminone pharmaceutical composition is an emulsifiable concentrate preparation, comprising 30-70% aromatic curcuminone mother material, 10-35% emulsifier, and 15-50% solvent by mass percentage; the aromatic curcuminone mother material is prepared by the following method: the turmeric rhizome raw material is dried and pulverized, then extracted with an aqueous ethanol solution to obtain an extract; the extract is concentrated and then extracted with an organic solvent to obtain an aqueous phase product and an oil phase product; the oil phase product is subjected to molecular distillation to obtain the aromatic curcuminone mother material; The application involves diluting the aromatic curcumin drug composition 150-600 times and applying it to cucumber plants, starting at the early stage of cucumber downy mildew, and applying it 2-3 times consecutively, with an interval of 5-7 days between each application.

2. The application according to claim 1, wherein, The aromatic curcumin pharmaceutical composition comprises, by weight percentage, 40-60% aromatic curcumin parent material, 20-30% emulsifier, and 15-35% solvent.

3. The application according to claim 1, wherein, The solvent is selected from any one or a combination of at least two of methyl oleate, soybean oil, corn oil, rapeseed oil or pine oil.

4. The application according to claim 1, wherein, The emulsifier is selected from nonionic emulsifiers and anionic emulsifiers. The nonionic emulsifier includes any one or a combination of at least two of the following: tristyrene phenol polyoxyethylene ether, sorbitan trioleate polyoxyethylene ether, tristyrene phenol-ethoxy-propoxylate, or castor oil polyglycol ether ester. The anionic emulsifier is selected from any one or a combination of at least two of the following: diphenyl sulfonate, α-olefin sulfonate, lignin sulfonate, ethoxylated alkylphenol sulfonate, alkoxylated arylphenol sulfonate, condensed naphthalene sulfonate, dodecylbenzene or tridecylbenzene sulfonate, naphthalene or alkylnaphthalene sulfonate, or sulfosuccinate.

5. The application according to claim 1, wherein, The emulsifier comprises, by weight percentage, 30-40% styrene phenol polyoxyethylene ether, 30-40% sorbitan trioleate polyoxyethylene ether and 25-35% calcium dodecylbenzene sulfonate.

6. The application according to any one of claims 1-5, wherein, The application includes diluting the aromatic curcumin pharmaceutical composition 150-300 times and applying it to cucumber plants.

7. The application according to claim 6, wherein, The application includes diluting the aromatic curcumin pharmaceutical composition 300 times and applying it to cucumber plants.

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