Application of linalyl acetate and method for preventing and treating field rice false smut and rice blast

Abstract

The invention belongs to the technical field of plant protection and biological control, and particularly relates to application of linalyl acetate and a method for controlling field rice false smut and rice blast. During field prevention and treatment, linalyl acetate, Tween-80 and water are mixed to prepare a solution; the rice is regularly treated, and the effect of preventing and treating field rice false smut and rice blast can be achieved. When the field rice false smut is prevented and treated, the final concentration of the linalyl acetate is 0.7 mg / L-0. 8mg / L; the final concentration of linalyl acetate is 1.4000 mg / L to 1.575 mg / L when the linalyl acetate is used for preventing and treating field rice blast. Researches show that linalyl acetate has a strong inhibition effect on hyphae and conidia of rice false smut and rice blast, and can prevent and treat rice false smut and rice blast.

Description

Technical Field

[0001] This invention belongs to the field of plant protection and biological control technology, specifically the application of linalyl acetate in the control of rice false smut and rice blast. Background Technology

[0002] Rice false smut and rice blast are two major fungal diseases of rice. False smut is a typical flowering-stage disease that primarily affects individual grains in the panicle. Rice blast can infect rice throughout its entire growth cycle, affecting multiple parts of the plant, including leaves, nodes, panicle neck, and grains. Both diseases severely impact rice yield, and both pathogens produce toxins that can harm human health. In recent years, climate change, altered cultivation practices, and the excessive application of nitrogen fertilizer have led to a significant increase in the affected area and severity of these two diseases. Currently, chemical pesticides remain the primary method for controlling rice false smut and rice blast.

[0003] Although rice false smut and rice blast are both fungal diseases, they are caused by different fungi. Therefore, while some broad-spectrum fungicides currently offer some control over both diseases, due to their different biological characteristics and sensitivities to fungicides, some broad-spectrum fungicides are only highly effective against one disease, while their effectiveness against the other is limited. There are few chemical fungicides available both domestically and internationally that offer good control over both rice false smut and rice blast. Furthermore, the long-term and excessive use of chemical fungicides not only pollutes the environment and harms human health but also accelerates the development of drug resistance in pathogens.

[0004] Given the long development time and high cost of creating new fungicides, researchers have begun searching for compounds with high activity against pathogens from natural products. For example, fungicides derived from plants such as allicin, osthol, and matrine have been registered for the control of various plant diseases. Therefore, it is crucial to develop a natural product that is environmentally friendly, has minimal toxicity, can replace chemical fungicides, and provides good control of both rice false smut and rice blast. Summary of the Invention

[0005] To address the problems in the prior art, the present invention aims to provide the application of linalyl acetate in the control of rice false smut and / or rice blast. It also aims to provide the application of linalyl acetate in inhibiting the mycelial growth of *Strombus oryzae* and / or the germination of conidia of *Strombus oryzae*. Antimicrobial tests have demonstrated that linalyl acetate has a strong inhibitory effect on the mycelia and conidia of *Strombus oryzae* and *Strombus oryzae*, and can control rice false smut and rice blast.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: One objective of this invention is to provide the application of linalyl acetate in the control of rice false smut and / or rice blast. Specifically, linalyl acetate can be used alone to control rice false smut; it can also be used alone to control rice blast; and it can simultaneously control both rice false smut and rice blast.

[0007] In this invention, the linalyl acetate used can be purchased directly from commercially available products or obtained using conventional extraction methods in the art.

[0008] Furthermore, the present invention provides the application of linalyl acetate in inhibiting the mycelial growth of rice false smut fungus and / or inhibiting the germination of conidia of rice false smut fungus.

[0009] Furthermore, the present invention also provides the application of linalyl acetate in inhibiting the mycelial growth of rice blast fungus and / or inhibiting the germination of rice blast fungus conidia.

[0010] Furthermore, when linaloacetate inhibits rice false smut pathogens, the concentration of linaloacetate is 0.2667 mg / L-0.8000 mg / L, and the final concentration of Tween-80 is 0.1 mg / L (the remainder is the rice false smut culture medium).

[0011] Furthermore, when linalyl acetate inhibits rice blast fungus, the concentration of linalyl acetate in the agent is 0.975 mg / L-1.575 mg / L, and the final concentration of Tween-80 is 0.1 mg / L (the remainder is rice blast fungus culture medium).

[0012] The second objective of this invention is to provide a method for preventing and controlling rice false smut in the field. The method includes the following steps: mixing linalyl acetate with Tween-80 to prepare a solution, and then treating rice regularly.

[0013] Furthermore, the final concentration of Tween-80 in the above solution is 0.1 mg / L.

[0014] Furthermore, in the above solution, the final concentration of linalool acetate is 0.7000 mg / L - 0.8000 mg / L.

[0015] Furthermore, when preventing and controlling rice false smut in the field, the rice should be treated regularly 2-3 days before the heading stage.

[0016] The third objective of this invention is to provide a method for preventing and controlling rice blast in the field, which includes the following steps: mixing linalyl acetate with Tween-80 to prepare a solution; and periodically treating rice.

[0017] Furthermore, the final concentration of Tween-80 in the solution was 0.1 mg / L.

[0018] Furthermore, the final concentration of linalyl acetate in the solution was 1.4000 mg / L-1.575 mg / L.

[0019] Furthermore, the control time for rice blast is 2-3 days before the rice heads break at the early booting stage and during the heading and flowering stage.

[0020] Furthermore, the present invention also provides a method for simultaneously preventing and controlling rice false smut and rice blast in the field. Specifically, 2-3 days before the rice heads break during the booting stage, a solution containing linalool acetate, Tween-80, and water is used to spray the rice. This method can effectively prevent and control both rice false smut and rice blast in the field.

[0021] Furthermore, the concentration of linaloacetate in the solution was 0.7000 mg / L to 0.8000 mg / L, and the final concentration of Tween-80 was 0.1 mg / L.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention provides the use of linalyl acetate in the control of plant diseases (especially rice false smut and rice blast). Studies on the toxicity of linalyl acetate to the mycelia and conidia of *Strombus oryzae* and its field control effects revealed that at treatment concentrations of 0.5333 mg / L and 0.800 mg / L, the mycelial inhibition rates of linalyl acetate against *Strombus oryzae* were 87.93% and 100%, respectively, both significantly better than the control agent (at the same concentration) osthol (41.61% and 45.33%). Therefore, linalyl acetate has an inhibitory effect on the mycelial growth of *Strombus oryzae*. With increasing linalyl acetate concentration, its inhibitory activity increases, and the EC50 of linalyl acetate against mycelia... 50 The value was 0.2362 mg / L, and the inhibitory activity was significantly better than that of the control drug osthol (EC). 50 The concentration was 1.857 mg / L, indicating that linalyl acetate also had a good inhibitory effect on conidial germination. At a concentration of 0.7000 mg / L, linalyl acetate inhibited the germination of rice false smut fungus conidia by 100%. (2) Linalool acetate has a good control effect on rice false smut. The control effect of 0.7000 mg / L linalool acetate on the diseased panicles of rice false smut is 85.42%, which is significantly different from the control agent of the same concentration (47.01%). (3) At treatment concentrations of linalyl acetate (0.975 mg / L and 1.575 mg / L), the mycelial inhibition rates of linalyl acetate against rice blast fungus were 57.56% and 100%, respectively, both significantly better than the control agent kasugamycin (33.71% and 57.67%). The inhibitory effect of linalyl acetate on the mycelial growth of rice blast fungus increased with increasing linalyl acetate concentration. The EC50 of linalyl acetate on the mycelial growth was... 50 The values ​​were 0.8782 mg / L, and the inhibitory activity was significantly better than that of the control drug osthol (EC). 50 The concentration was 1.479 mg / L. Linaloacetate also showed good inhibitory effects on conidial germination; at 1.4000 mg / L, the inhibition rate of conidial germination by linaloacetate was 100%. Linaloacetate also showed good control effects against rice blast; the control effect of 1.4000 mg / L linaloacetate on diseased panicles of rice blast was 89.49%, which was significantly different from the control agent of the same concentration (57.86%). Attached Figure Description

[0023] Figure 1 The inhibitory effect of linalyl acetate on the mycelium of rice false smut fungus; Figure 2 The inhibitory effect of linalyl acetate on the mycelium of rice blast fungus. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0027] In this invention, some conventional operating equipment, devices and components have been omitted or only briefly described.

[0028] Unless otherwise specified in the examples, the conditions shall be performed according to the standard conditions or the conditions recommended by the manufacturer.

[0029] In this application, unless otherwise specified, % refers to its mass percentage content.

[0030] Example 1: 1. Test materials 1.1 Test Reagent Linaloyl acetate was purchased from Jiangxi Xinsen Natural Plant Oil Co., Ltd.

[0031] Tween-80 is domestically produced analytical grade.

[0032] 1.2 Test Culture Medium Potato sucrose agarose medium (PSA) and potato sucrose liquid medium (PSB).

[0033] 1.3 Test pathogens (1) Isolation and identification of rice false smut pathogen Rice false smut samples from naturally occurring rice plants were collected in the field in 2022, exhibiting typical yellow blasted grain symptoms. The blasted grain samples were isolated and purified to obtain a single purified strain of *Strombus oryzae*. The colony morphology of the isolated strain on PDA medium was consistent with previously reported *Strombus oryzae* colonies (Fu Rongtao, 2014). Genomic DNA was then extracted from the purified strain, and PCR amplification and sequencing were performed using primers specific to the *Strombus oryzae* ITS sequence. The ITS sequence of the isolated strain was compared with the *Strombus oryzae* sequence in the NCBI GenBank database. The similarity between the isolated strain and the *Strombus oryzae* sequence in GenBank (accession number: AB105954) was 100%. Therefore, the isolated strain was identified as *Strombus oryzae*. The isolated *Strombus oryzae* was then stored at -20℃ for future use.

[0034] (2) Isolation and identification of rice blast fungus In 2022, rice blast disease samples from naturally occurring rice plants were collected in the field. These samples were then isolated and purified to obtain a single purified strain of *Strombus oryzae*. The colony morphology and spore morphology of the isolated strain on the culture medium were consistent with those previously reported (Yu et al., 2014). Genomic DNA was then extracted from the purified strain, and PCR amplification and sequencing were performed using primers specific to the *Strombus oryzae* ITS sequence. The ITS sequence of the isolated strain was compared with the *Strombus oryzae* sequence in the NCBI GenBank database. The sequence of the isolated strain showed 100% homology with the sequence of the strain in the GenBank database (accession number: MH590369.1). Therefore, the strain isolated in this experiment was *Strombus oryzae*. The isolated *Strombus oryzae* strain was then stored at -20℃ for future use.

[0035] The isolation and identification of rice false smut and rice blast are both existing technologies.

[0036] 1.4 Rice varieties tested The rice varieties 'Guichao 2', which are susceptible to rice false smut, and 'Mianhui 725', which are susceptible to rice blast, were selected.

[0037] 2. Experimental Methods and Results Experiment 2.1 Inhibitory effect of linalyl acetate on the mycelial growth of rice false smut fungus: The mycelial growth rate inhibition method was used to determine the indoor toxicity of *Strombus oryzae* hyphae. Under aseptic conditions, linalyl acetate and Tween-80 were filtered through a bacterial filter to obtain sterile linalyl acetate and Tween-80, respectively. 2 g of sterile linalyl acetate was mixed with 1 mL of Tween-80 to prepare a mixed solution with a concentration of 667 mg / L. Seven drug-containing media were prepared by adding 20 μL, 40 μL, 80 μL, 100 μL, 120 μL, 150 μL, and 200 μL of the drug solution to 100 mL of PSA medium to prepare final concentrations of 0.133 mg / L, 0.267 mg / L, 0.533 mg / L, 0.667 mg / L, 0.800 mg / L, 1.000 mg / L, and 1.333 mg / L, respectively. The drug-containing PSA medium was poured into petri dishes. The final concentrations of the control drug osthol were also 0.133 mg / L, 0.267 mg / L, 0.533 mg / L, 0.667 mg / L, 0.800 mg / L, 1.000 mg / L, and 1.333 mg / L. A drug-free medium containing 0.1 mg / L Tween-80 was used as a control. The media were prepared using 6... Cut edge hyphae of *Strombus oryzae* using a mm punch and inoculate them into the center of a PSA-containing culture dish. Each concentration treatment was repeated 5 times. The dishes were incubated in the dark at 26°C. After 8 days, the colony diameter was measured using the cross-cross method, and the inhibition rate of each treatment was calculated.

[0038] The formula for calculating the mycelial growth inhibition rate is as follows: Mycelial growth inhibition rate = [(control colony diameter - mycelial cake diameter) - (treatment colony diameter - mycelial cake diameter)] / (control colony diameter - mycelial cake diameter) × 100.

[0039] The results are shown in Table 1 and... Figure 1 The virulence regression equation and effective final concentration (EC50) were calculated based on the concentration and inhibition rate. 50 ).

[0040] Table 1. Inhibition rate (%) of linalyl acetate on mycelial growth of rice false smut fungus.

[0041] As shown in Table 1, at concentrations of 0.2667 mg / L and 0.8000 mg / L, linalool acetate inhibited the mycelial growth of rice false smut fungus by 64.66% and 100%, respectively, both significantly higher than the inhibition rates of the control agent osthol (35.32% and 45.33%).

[0042] Table 2. Toxicity of linalyl acetate against rice false smut mycelium

[0043] Table 2 shows that linalyl acetate has a strong inhibitory activity on the mycelial growth of *Rhizoctonia solani*, and its inhibitory activity increases with increasing linalyl acetate concentration. (EC50) 50 The value was 0.2181 mg / L, and the inhibitory activity was significantly better than that of the control drug osthol (EC). 50 (Value 1.857 mg / L).

[0044] Experiment 2.2 Inhibitory effect of linalyl acetate on the germination of conidia of rice false smut fungus: Collection of conidia of *Strombus oryzae*: The *Strombus oryzae* strain isolated and preserved in the laboratory was activated on PSA medium and cultured for approximately 14 days. Mycelial blocks from the edges of the mycelia were picked and inoculated into sterile PSB liquid medium. The medium was then incubated at 26°C and 140 rpm for 8 days using a shaker. Under sterile conditions, the mycelia were filtered through gauze, and conidia were collected by centrifugation. The conidia were then resuspended in PSB liquid to prepare a spore concentration of 10-1. 6 Prepare a spore suspension of 1 spore per mL for later use.

[0045] The inhibitory effect of linalool acetate on conidia of *Strombus haemolyticus* was determined using a spore germination assay: 0.2 g of linalool acetate was mixed with 0.1 mL of Tween-80 and diluted to a final volume of 10 g / L with 19.7 mL of sterile water to prepare a stock solution, in which the concentration of Tween-80 was 10 mg / L. Then, 3 μL, 6 μL, and 7 μL of the stock solution were added to 2 mL centrifuge tubes containing 1 mL of PSB liquid medium, respectively, to prepare PSB liquid medium with final concentrations of 0.3000 mg / L and 0.6000 mg / L. 1 μL of *Strombus haemolyticus* conidia suspension was added to the PSB liquid medium, with a control of 0.1 mg / L Tween-80 in untreated medium. Each concentration was repeated three times. The inhibitory effect of the control agent osthol on *Strombus haemolyticus* conidia was the same as above. Centrifuge tubes containing the drug-containing culture medium were placed in a constant temperature shaker at 26℃ and cultured at 140 rpm for 3 days. Spore germination was then observed under a microscope.

[0046] The formula for calculating the spore germination inhibition rate is as follows: Spore germination inhibition rate = (number of germinating control spores) (Number of germinating spores in the treatment) / (Number of germinating spores in the control) × 100%.

[0047] The results of spore germination inhibition rate are shown in Table 3.

[0048] Table 3. Inhibition of sporulation by linalyl acetate on rice false smut (%)

[0049] Table 3 shows that linalyl acetate has a strong inhibitory effect on the conidia of rice false smut. At a concentration of 0.7000 mg / L, linalyl acetate achieved a 100% inhibition rate on the conidia.

[0050] Therefore, linalyl acetate can be used to control rice false smut.

[0051] Example 2: The field control effect of linalyl acetate on rice false smut was tested using the same materials as in Example 1.

[0052] The field control efficacy of linalool acetate against rice false smut was tested using a spray method. The susceptible rice variety Guichao 2 was selected for the experiment. The rice was planted in an experimental paddy field and managed with conventional water and fertilizer.

[0053] For fertilization from the early tillering stage to the heading stage of rice, as well as the application time and amount of fungal soil, refer to the invention patent "A Simple Method for Identifying Rice False Scab Resistance" (201910776427.3), and create suitable environmental conditions for the occurrence of rice false scab. The reagents and dosages used in this experiment were: 0.6000 mg / L, 0.7000 mg / L, and 0.8000 mg / L linalool acetate (containing 0.1 mg / L Tween-80) and 0.6000 mg / L, 0.7000 mg / L, and 0.8000 mg / L 1% osthol water-in-oil emulsion. Each treatment was sprayed with water as a control. The experiment consisted of five different treatments, as detailed below: Treatment 1: Spraying with 0.6000 mg / L, 0.7000 mg / L, and 0.8000 mg / L linalyl acetate solutions 2-3 days before the heading stage of rice; Treatment 2: Spraying with 0.6000 mg / L, 0.7000 mg / L, and 0.8000 mg / L linalyl acetate solutions 5-6 days before the heading stage of rice. Treatment 3: Two to three days before the rice heading stage, spray with 1% osthol emulsion at concentrations of 0.6000 mg / L, 0.7000 mg / L, and 0.8000 mg / L respectively. Treatment 4: Five to six days before the rice heading stage, spray with 1% osthol emulsion at concentrations of 0.6000 mg / L, 0.7000 mg / L, and 0.8000 mg / L respectively. Treatment 5: Spraying with clean water as a control.

[0054] Each treatment had 3 replicates, and each replicate had 20 m. 2 Spray the entire plant with pesticide until water drips from the surface of the rice panicles, i.e., 30L~45L of pesticide solution per acre. During the yellow ripening stage of rice, investigate the number of diseased panicles and calculate the disease rate, disease index, and control effect.

[0055] Rice blast disease severity grading standards: Grade 0 (highly resistant): incidence rate 0%; Grade 1 (resistant): incidence rate 0.1-3.0%; Grade 3 (moderately resistant): incidence rate 3.1-7.0%; Grade 5 (moderately susceptible): incidence rate 7.1-15.0%; Grade 7 (susceptible): incidence rate 15.1-25.0%; Grade 9 (highly susceptible): incidence rate > 25.1%.

[0056] Rice blast disease severity grading standards: Grade 0: Disease-free, highly resistant (HR); Grade 1: Incidence rate less than 5%, resistant (R); Grade 3: Incidence rate less than 5.1-10%, moderately resistant (MR); Grade 5: Incidence rate less than 10.1-25%, moderately susceptible (MS); Grade 7: Incidence rate less than 25.1-50%, susceptible (S); Grade 9: Incidence rate less than 50.1-100%, highly susceptible (HS).

[0057] Incidence rate (%) = (Number of infected ears / Total number of ears surveyed) × 100; Disease control efficacy (%) = [(Disease incidence in the control area with clean water - Disease incidence in the treated area) / Disease incidence in the control area with clean water] × 100; Disease index = [∑(number of diseased ears at each level × representative value at each level) / (total number of ears surveyed × highest level representative value)] × 100; Disease control efficacy (%) = [(Disease index of water control area - Disease index of drug-treated area) / Disease index of water control area] × 100.

[0058] The results of the field efficacy trials are shown in Table 4: Table 4. Field efficacy test results of linalool acetate against rice false smut.

[0059] Table 4 shows that spraying rice with a 0.7000 mg / L to 0.8000 mg / L linalyl acetate solution 2-3 days before heading in the rice booting stage has a good control effect on rice false smut, with a disease control efficacy of 85.42% to 88.98%, significantly higher than the control efficacy of osthol (47.01% to 48.1%). Simultaneously, it also showed a good preventive effect against rice blast, with a control efficacy of 71.6% to 72.36%. Therefore, the experimental results indicate that 0.7000 mg / L to 0.8000 mg / L linalyl acetate 2-3 days before heading in the rice booting stage has a good control effect on both rice false smut and rice blast. Example 3: The inhibitory effect of linalyl acetate on the mycelial growth of rice blast fungus was investigated using the same experimental materials as in Example 1. The mycelial growth rate inhibition method was used to determine the virulence of rice blast fungus mycelium in the laboratory. Under aseptic conditions, linalyl acetate and Tween-80 were filtered through a bacterial filter to obtain sterile linalyl acetate and Tween-80, respectively. Mix 2 g of sterile linalool acetate with 1 mL of Tween-80 to prepare a 667 mg / L mixed solution. Add 35, 70, 80, 100, 130, 160, 190, and 210 μL of this solution to 100 mL of PSA medium to prepare seven drug-containing media with final concentrations of 0.2625, 0.525, 0.75, 0.975, 1.200, 1.425, and 1.575 mg / L. PSA medium containing the drug is poured into petri dishes. The final concentrations of the control drug, kasugamycin, are also 0.2625, 0.525, 0.75, 0.975, 1.2, 1.425, and 1.575 mg / L. A drug-free medium containing 0.1 mg / L Tween-80 serves as the control. (The last sentence appears to be incomplete and requires further context.) Cut edge hyphae of *Strombus oryzae* using a mm punch and inoculate them into the center of a PSA-containing culture dish. Each concentration treatment was repeated 5 times. The dishes were incubated in the dark at 26°C. After 8 days, the colony diameter was measured using the cross-cross method, and the inhibition rate of each treatment was calculated.

[0060] The formula for calculating the mycelial growth inhibition rate is as follows: Mycelial growth inhibition rate = [(Control colony diameter - Mycelial cake diameter) - (Treatment colony diameter - Mycelial cake diameter)] / (Control colony diameter - Mycelial cake diameter) × 100. The results are shown in Table 1 and... Figure 1 The virulence regression equation and effective final concentration (EC50) were calculated based on the concentration and inhibition rate. 50 ).

[0061] Table 5. Inhibition rate (%) of linalyl acetate on mycelial growth of rice blast fungus.

[0062] As shown in Table 5, at concentrations of 0.975 mg / L and 1.575 mg / L, linalool acetate inhibited the mycelial growth of rice blast fungus by 57.56% and 100%, respectively, both significantly higher than the inhibition rates of the control agent osthol (35.32% and 57.67%). Table 6. Virulence of linalyl acetate against rice blast fungus mycelium

[0063] Table 6 shows that linalyl acetate has a strong inhibitory activity on the mycelial growth of rice blast fungus. The inhibitory activity increases with increasing linalyl acetate concentration. 50 The value was 0.8782 mg / L, and the inhibitory activity was significantly better than that of the control drug osthol (EC). 50 (Value 1.479 mg / L).

[0064] Inhibitory effect of linalyl acetate on the germination of conidia of rice blast fungus Collection of conidia of *Strombus oryzae*: The *Strombus oryzae* strain isolated and preserved in the laboratory was activated on PSA medium and cultured for about 8 days. Mycelial blocks from the edge of the *Strombus oryzae* hyphae were picked and inoculated into sterile PSB liquid medium. The medium was placed in a constant temperature shaker at 26℃ and 140 rpm for 8 days. Then, under sterile conditions, the mycelia were filtered through gauze, and the conidia were collected by centrifugation. The conidia were then resuspended in PSB liquid to prepare a spore concentration of 10. 6 Prepare a spore suspension of 1 spore per mL for later use.

[0065] Spore germination assays were performed using linalool acetate and osthol. 0.2 g of linalool was mixed with 0.1 mL of Tween-80, and 19.7 mL of sterile water was added to bring the volume to 10 g / L, with the Tween-80 concentration at 10 mg / L. 8 and 14 μL of the stock solution were added to 2 mL centrifuge tubes containing 1 mL of PSB liquid medium, respectively, to prepare drug-containing medium with final concentrations of 0.8000 and 1.4000 mg / L. 1 μL of rice false spore suspension was added to the drug-containing PSB liquid medium, with a drug-free medium containing 0.1 mg / L Tween-80 as a control. Each concentration was repeated three times. The centrifuge tubes containing the drug-containing medium were incubated at 26℃ and 140 rpm for 3 days, and spore germination was observed under a microscope. Spore germination inhibition rate = (number of germinating control spores) / (number of germinating control spores). (Number of germinating spores in the treatment) / (Number of germinating spores in the control) × 100%. The results are shown in Table 7.

[0066] Table 7. Inhibition of rice blast fungus conidia germination by linalyl acetate (%)

[0067] Table 7 shows that linalyl acetate has a strong inhibitory effect on the conidia of rice blast fungus. At a concentration of 1.4000 mg / L, linalyl acetate achieved a 100% inhibition rate against rice blast fungus spores.

[0068] Example 4: Field control effect of linalyl acetate on rice blast. The field control efficacy of linalyl acetate against rice blast was tested using a spray method. The susceptible rice variety Mianhui 725 was selected for the experiment. The rice was planted in an experimental paddy field and managed with conventional water and fertilizer. The reagents and dosages used in this experiment were: 1.2000 mg / L, 1.4000 mg / L, and 1.575 mg / L linalool acetate solution (containing 0.1 mg / L Tween-80) and 1.2000 mg / L, 1.4000 mg / L, and 1.575 mg / L kasugamycin solution. Each treatment was sprayed with water as a control. The experiment consisted of 7 different treatments, as detailed below: Treatment 1: Spray treatment with 1.2000 mg / L, 1.4000 mg / L, and 1.575 mg / L linalyl acetate solution 2-3 days before the rice heading stage and during the heading stage, respectively. Treatment 2: During the heading and flowering stage of rice, spray treatments were carried out with 1.2000 mg / L, 1.4000 mg / L, and 1.575 mg / L linalyl acetate solutions, respectively. Treatment 3: At the heading and panicle stage of rice, spray treatments were carried out with 1.2000 mg / L, 1.4000 mg / L, and 1.575 mg / L linalyl acetate solutions, respectively. Treatment 4: Spray treatment with 1.2000 mg / L, 1.4000 mg / L, and 1.575 mg / L linalyl acetate solution 2-3 days before the heading stage of rice and at the heading stage of rice, respectively. Treatment 5: During the heading and flowering stage of rice, spray treatments were carried out with 1.2000 mg / L, 1.4000 mg / L, and 1.575 mg / L kasugamycin solutions, respectively. Treatment 6: During the heading and panicle stage of rice, spray with 1.2000 mg / L, 1.4000 mg / L, and 1.575 mg / L kasugamycin solution respectively; Treatment 7: Spray with clean water as a control.

[0069] Each treatment had 3 replicates, and each replicate had 20 m. 2 Spray the entire plant with pesticide until water drips from the surface of the rice panicles, i.e., 30L~45L of pesticide solution per acre. During the yellow ripening stage of rice, investigate the number of diseased panicles and calculate the disease rate, disease index, and control effect.

[0070] Rice blast disease severity grading standards: Grade 0: Disease-free, highly resistant (HR); Grade 1: Incidence rate less than 5%, resistant (R); Grade 3: Incidence rate less than 5.1-10%, moderately resistant (MR); Grade 5: Incidence rate less than 10.1-25%, moderately susceptible (MS); Grade 7: Incidence rate less than 25.1-50%, susceptible (S); Grade 9: Incidence rate less than 50.1-100%, highly susceptible (HS).

[0071] Disease index = [∑(number of diseased ears at each level × representative value at each level) / (total number of ears surveyed × highest level representative value)] × 100; Disease control efficacy (%) = [(Disease index of water control area - Disease index of drug-treated area) / Disease index of water control area] × 100.

[0072] The results of the field efficacy trials are shown in Table 8: Table 8. Field control efficacy of linalyl acetate against rice blast (%)

[0073] Table 8 shows that spraying rice with a 1.4000 mg / L–1.575 mg / L linalyl acetate solution 2–3 days before heading and during the heading stage of rice effectively controlled rice blast, achieving a control efficacy of 89.49%–91.28%, significantly higher than the control efficacy of osthol (57.86%–63.16%). Simultaneously, it also showed good control efficacy against rice false smut, achieving a control efficacy of 80.1%–84.18%. Furthermore, spraying rice with a 1.4000 mg / L–1.575 mg / L linalyl acetate solution during the heading stage also demonstrated good control efficacy against rice blast, achieving a control efficacy of 81.12%–84.33%, significantly better than the control efficacy of osthol (57.86%–63.16%). Therefore, the experimental results show that 1.4000 mg / L to 1.575 mg / L linalyl acetate solution has a good control effect on rice blast and rice false smut 2-3 days before the heading stage and during the heading stage of rice; while during the heading stage of rice, 1.4000 mg / L to 1.575 mg / L linalyl acetate solution shows a good control effect on rice blast.

[0074] In summary, the linalyl acetate provided by this invention has a significant inhibitory effect on the mycelial growth and conidial germination of rice false smut and rice blast, effectively controlling these diseases. In the field, the control efficacy against rice false smut reaches 88.98%, and the control efficacy against rice blast reaches 91.28%. Linalyl acetate is a natural plant product, readily available, environmentally friendly, and highly safe for humans and livestock.

[0075] The above embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any modifications, refinements, or combinations made under the main design and principles of the present invention, which solve technical problems consistent with the present invention, are considered to be within the protection scope of the present invention.

Claims

1. Application of linalyl acetate in preventing and treating rice false smut and / or rice blast.

2. Use according to claim 1, characterized in that: In the prevention and treatment of rice false smut, linalyl acetate can inhibit the growth of rice false smut mycelium and / or inhibit the germination of rice false smut conidia; in the prevention and treatment of rice blast, linalyl acetate can inhibit the growth of rice blast mycelium and / or inhibit the germination of rice blast conidia.

3. Use according to claim 1 or 2, characterized in that: In the inhibition of rice false smut, the concentration of linalyl acetate is 0.2667 mg / L-0.8000 mg / L, and the final concentration of Tween-80 is 0.1 mg / L.

4. Use according to claim 1 or 2, characterized in that: In the inhibition of rice blast, the concentration of linalyl acetate in the medicament is 0.975 mg / L-1.575 mg / L, and the final concentration of Tween-80 is 0.1 mg / L.

5. A method of controlling rice blast in a field of rice plants, comprising applying to the rice plants a fungicidal composition comprising a compound of Formula (I) or a salt thereof. The method comprises the following steps: Mixing linalyl acetate, Tween-80 and water to prepare a solution; and regularly treating rice.

6. The method of claim 5, wherein: The final concentration of Tween-80 in the solution is 0.1 mg / L, and the final concentration of linalyl acetate is 1.4000 mg / L-1.575 mg / L.

7. The method according to claim 5 or 6, characterized in that: The time for regularly treating rice is 2-3 days before the initial break of the rice booting stage and the break of the rice booting stage.

8. A method of simultaneously controlling rice false smut and rice blast in rice in the field, characterized by The method comprises the following steps: Mixing linalyl acetate, Tween-80 and water to prepare a solution; Regularly treating rice.

9. The method of claim 8, wherein: The final concentration of Tween-80 in the solution is 0.1 mg / L, and the final concentration of linalyl acetate is 0.700 mg / L-0.800 mg / L.

10. The method of claim 8 or 9, characterized in that: The time for regularly treating rice is 2-3 days before the initial break of the rice booting stage.

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