2-heptanone for use in the preparation of a preparation for controlling plant diseases

Abstract

The application relates to the field of agricultural biotechnology and plant protection, and specifically provides application of 2-heptanone in preparation of a preparation for preventing and treating plant diseases, the 2-heptanone has broad-spectrum bacteriostasis, and has strong bacteriostasis on colletotrichum gloeosporioides, colletotrichum acutatum, mycosphaerella musicola, colletotrichum caricae, fusarium graminearum, colletotrichum musae, fusarium solani, fusarium oxysporum, colletotrichum musae, and fusarium verticillioides. The fumigant for preventing and treating plant pathogens developed based on the 2-heptanone is expected to be used for preventing and treating complex diseases caused by various pathogens, or comprehensively preventing and controlling different crop diseases in a crop rotation system, and has important development value.

Description

Technical Field

[0001] This invention belongs to the field of agricultural biotechnology and plant protection, and relates to the application of 2-heptanone in the preparation of agents for the prevention and control of plant diseases. Background Technology

[0002] Important economic crops such as bananas, lychees, strawberries, mangoes, papayas, tomatoes, wheat, and corn are frequently infected by various pathogenic fungi during their growth and post-harvest storage, leading to severe yield and quality losses. For example, anthracnose caused by *Colletotrichum* spp., and wilt, Fusarium head blight, and root rot caused by *Fusarium* spp., are all highly damaging plant diseases. Currently, the control of these diseases still relies heavily on chemical fungicides, but long-term use can easily lead to pathogen resistance, pesticide residues, and environmental pollution. Therefore, developing efficient, safe, and environmentally friendly new green control technologies has become an urgent need for sustainable agricultural development.

[0003] Fumigation, as a non-contact plant protection method, shows great potential in the post-harvest preservation and storage disease control of fruits and vegetables due to its unique mechanism of action (through gas diffusion), ability to treat hidden areas, and generally lack of direct residue. However, the types of fumigants currently available are limited, and some traditional fumigants have problems such as high toxicity, residue, or narrow applicability. Therefore, finding widely available, highly antibacterial, easily degradable, and safe fumigation active substances is an important research direction in this field.

[0004] 2-Heptanone is a naturally occurring volatile small-molecule ketone compound. Currently, published reports on 2-heptanone mainly focus on its role as an insect pheromone, food flavoring agent, or metabolite of certain microorganisms. To date, no published literature has indicated or revealed that 2-heptanone has inhibitory activity against various important plant pathogenic fungi, including *Fungiella lychee*, *Fungiella fragilis*, *Fungiella mango*, *Fungiella papaya*, *Fusarium oxysporum*, *Fusarium oxysporum*, *Fusarium oxysporum*, and *Fusarium solani*, and there is no indication of its application as a fumigant-type fungicidal active ingredient in plant disease control.

[0005] Therefore, in view of the technical problem that the selection of efficient and safe fumigation active substances is limited in the existing technology, the present invention aims to provide a new use of compound 2-heptanone in the field of agricultural plant protection for the first time, in particular as a fumigant to inhibit the growth of a variety of plant pathogens, so as to fill the technical gap and provide a new solution for green plant protection. Summary of the Invention

[0006] The purpose of this invention is to provide a novel application of 2-heptanone, specifically its application in inhibiting various plant pathogens; and to provide a highly efficient, safe, and environmentally friendly fumigant containing 2-heptanone, as well as a corresponding non-contact fumigation method, to solve the problems of defects in existing chemical fungicides and insufficient fumigants in the prevention and control of plant diseases.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] (a) Applications of 2-Hepanotone

[0009] 2-Heptanone can be used to inhibit one or more of the following fungi: *Colletotrichum gloeosporioides* (lychee anthracnose), *Colletotrichum fragariae* (strawberry anthracnose), *Pestalotiopsis mangiferae* (mango leaf blight), *Colletotrichum gloeosporioides* (papaya anthracnose), *Fusarium graminearum* (wheat scab), *Colletotrichum gloeosporioides* (mango anthracnose), *Fusarium oxysporum f.sp. lycopersici* (tomato wilt), *Fusarium oxysporum f.sp. cubense* (banana wilt), *Colletotrichum musae* (banana anthracnose), and *Fusarium graminearum* (corn root rot).

[0010] Specifically, 2-heptanone exerts its fumigation effect in gaseous form, achieving a bacteriostatic effect by inhibiting the germination of plant pathogens' spores and / or the growth of their mycelia. In particular, it has an irreversible killing effect on pathogen spores and a significant inhibitory effect on mycelial growth.

[0011] Meanwhile, 2-heptanone can be used to prepare fumigants that inhibit the above-mentioned plant pathogens, with 2-heptanone as the core active ingredient.

[0012] (ii) Fumigants that inhibit plant pathogens

[0013] A fumigant for inhibiting plant pathogens, characterized in that it contains 2-heptanone as an active ingredient, wherein the plant pathogen is at least one of the following: *Lychee anthracnose*, *Strawberry anthracnose*, *Mango leaf blight*, *Papaya anthracnose*, *Wheat scab*, *Mango anthracnose*, *Tomato wilt*, *Bacterium wilt*, *Bacterium anthracnose*, and *Maize root rot*.

[0014] When the plant pathogen is *Anthracnose glomeratus*, the effective concentration of 2-heptanone in the fumigant is 0.05~8.00 mL / L, and its half-maximum effective concentration (EC50) is... 50 The concentration was 0.334 mL / L; among which, a concentration ≥6.00 mL / L could completely inhibit the anthracnose fungus of banana, and a concentration ≥2×EC 50 It can persistently and completely inhibit the germination of banana anthracnose spores and destroy their cell structure.

[0015] The fumigant can be further modified by adding agriculturally acceptable additives, such as stabilizers and slow-release agents, according to the actual application scenario, to optimize its fumigation effect and duration of effectiveness.

[0016] (III) Non-contact fumigation methods for inhibiting plant pathogens

[0017] A non-contact fumigation method for inhibiting plant pathogens involves applying the above-mentioned fumigant containing 2-heptanone in a closed or semi-closed space to create a 2-heptanone gaseous environment with antibacterial activity, thereby inhibiting the growth of plant pathogens in the space; wherein the plant pathogens are at least one of the above 10 pathogens.

[0018] When the plant pathogen is *Anthracnose glomeratus*, the effective dosage of 2-heptanone is 0.05–8.00 mL / L per unit volume of the fumigation space. This method achieves non-contact antibacterial action through gas diffusion, can treat hidden parts of plants, and is suitable for disease control in post-harvest storage and logistics transportation of fruits and vegetables.

[0019] The beneficial effects of this invention are:

[0020] (1) Highly effective antibacterial activity: 2-Heptanone has inhibitory effects on 10 important plant pathogens, with inhibition rates of over 90% against litchi anthracnose and strawberry anthracnose; against banana anthracnose, a concentration as low as 0.05 mL / L can produce an inhibitory effect of 27.08%, and a concentration of 6.00 mL / L can achieve complete inhibition, EC 100%. 50 With a concentration of only 0.334 mL / L, its antibacterial efficiency is significant.

[0021] (2) Broad spectrum of effects: It covers a variety of pathogens related to postharvest diseases, leaf diseases and soil-borne diseases of fruits. It can be used to control complex diseases or integrated disease control in crop rotation systems. It has a wide range of applications.

[0022] (3) Safety and environmental protection: 2-Hepagon is a naturally occurring volatile compound that is easily degraded and has no direct residue risk. It avoids the drug resistance and environmental pollution problems caused by chemical fungicides and meets the needs of green agricultural development.

[0023] (4) Superior mode of action: It adopts fumigation method, which is non-contact and can treat the hidden parts of plants. It is suitable for post-harvest preservation and storage of fruits and vegetables. It is easy to operate and does not damage the quality of plants or fruits.

[0024] (5) Clear mechanism of action: It inhibits bacteria by destroying the cell structure of pathogenic spores and hyphae, inhibiting spore germination and hyphal growth, and has an irreversible killing effect on spores, with stable and reliable control effect. Attached Figure Description

[0025] Figure 1 This study determined the toxicity of 2-heptanone against *Bacillus anthracis*.

[0026] Figure 2 Treatments with different concentrations of 2-heptanone were used to inhibit the germination and morphology of banana anthracnose spores.

[0027] Figure 3 The inhibitory effect of different concentrations of 2-heptanone on the growth of banana anthracnose colonies at different time points was investigated.

[0028] Figure 4 This study aimed to observe the morphological effects of 2-heptanone volatile gas on the mycelium of banana anthracnose using the KEYENCE digital microscopy system.

[0029] Figure 5 The effect of 2-heptanone treatment on the ultrastructure of *Bacillus anthracis*.

[0030] Figure 6 This demonstrates the broad-spectrum antibacterial effect of 2-heptanone volatile gas against a variety of plant pathogens. Detailed Implementation

[0031] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0032] Example 1: Determination of the toxicity of the volatile active substance 2-heptanone to *Bacillus anthracis* of banana.

[0033] Methods: The virulence of 2-heptanone against *Anthracis bananais* was determined using the plate fumigation method. Filter paper discs containing different volumes of analytical grade 2-heptanone standard were placed in the center of the lid of sterile petri dishes, resulting in final concentrations of 0.05, 0.10, 0.25, 0.50, 1.00, 2.00, 4.00, 6.00, and 8.00 mL / L in a sealed environment. A blank control was prepared by adding an equal volume of sterile water.

[0034] Invert a PDA plate containing 5 mm diameter banana anthracnose mycelial cakes onto the plate lid, immediately seal with Parafilm, and incubate at 28°C. Once the control group colonies have fully colonized the plate, measure the colony diameter for each treatment group using the cross-sectional method. Three replicates were performed for each concentration. The inhibition rate was calculated using the following formula:

[0035]

[0036] Using SPSS statistical software, linear regression analysis was performed with the logarithm of 2-heptanone concentration (x) as the independent variable and the probability of inhibition rate (y) as the dependent variable to establish a virulence regression equation and calculate the half-maximal effect concentration (EC50). 50 ).

[0037] Results and Analysis: The fumigation toxicity test results of 2-heptanone against *Anthracis aureus* of banana showed that the inhibitory effect of 2-heptanone gas on *Anthracis aureus* of banana was significantly concentration-dependent. Figure 1 Within a concentration gradient from 0.05 mL / L to 8.00 mL / L, the inhibition rate continuously increased with increasing 2-heptanone concentration. At a concentration of 0.05 mL / L, the inhibition rate was 27.08%; at 1.00 mL / L, it increased to 62.50%; at 4.00 mL / L, the inhibition rate reached as high as 92.50%; and at concentrations of 6.00 mL / L and above, the inhibitory effect on the pathogen reached 100%, achieving complete inhibition.

[0038] Further virulence regression analysis showed that the virulence regression equation of 2-heptanone against *Anthracis bananais* was: The coefficient of determination (R²) was 0.889, indicating a good linear relationship between concentration and inhibitory effect. Based on this equation, the half-maximum effective concentration (EC50) of 2-heptanone against *Anthracis bananais* was calculated. 50 The concentration was 0.334 mL / L. This result clarifies the effective concentration range of 2-heptanone as a volatile fumigant, providing crucial dosage data for its practical application as a postharvest preservative.

[0039] Example 2: Effects of the volatile active substance 2-heptanone on the germination and morphology of banana anthracnose spores

[0040] Method: Take a fresh spore suspension of *Bacillus anthracis* (1×10⁻⁶). 6 50 μL of spores / mL was mixed with 2-heptanone solutions of different concentrations (set to 1×EC). 50 2×EC 50 4×EC 50 8×EC 50A mixture of equal volumes of spores (with equal gradients) was prepared on concave glass slides and mixed with sterile water, serving as a control (CK). The concave slides were placed in moistened petri dishes and incubated at 28°C. At least 200 spores were randomly observed under a microscope at 12, 24, and 36 hours to calculate the spore germination rate. Germination was defined as a germ tube length exceeding half the spore diameter. Simultaneously, morphological changes in the spores were observed and recorded using an optical microscope.

[0041] Results and Analysis: 2-Heptanone fumigation treatment showed a strong and sustained inhibitory effect on the germination of *Anthracis banyanica* spores and induced significant morphological changes in the spores. This effect was significantly concentration- and time-dependent. Figure 2 ).

[0042] Regarding spore germination rate ( Figure 2 (A) There were highly significant differences in spore germination rates among the treatment groups at different observation time points. In the early stage of culture (12 h), ≥2×EC 50 The spore germination rate in the treatment group was suppressed to an extremely low level (1.56%), significantly lower than that in the CK group (87.64%) and 1×EC. 50 Treatment group (89.71%) (p < 0.05). By 24 h, 1×EC 50 The antibacterial effect of the treatment group was fully demonstrated, with the germination rate dropping sharply to 14.55%, while ≥2×EC 50 The treatment group achieved complete suppression (germination rate 0.00%). Notably, at the 36-hour observation endpoint, ≥2×EC 50 The treatment group maintained near-complete inhibition, while 1×EC 50 The spore germination rate in the treatment group showed a significant rebound, reaching 78.73%, indicating that this sub-lethal concentration may only delay spore germination rather than completely kill them. Once the fumigation effect weakens due to factors such as natural volatilization, the surviving spores can still regain their germination ability. In contrast, the spores in the control group germinated rapidly within 24 hours and entered a plateau phase, with the germination rate consistently remaining above 99%.

[0043] Regarding spore morphology ( Figure 2 (B) The direct destructive effect of 2-heptanone on spores was revealed by optical microscopy. Control group (CK): Spores were plump, spindle-shaped with pointed ends, and smooth. After culture, the vast majority of spores germinated normally, producing uniform and robust germ tubes, which further developed into normal hyphae. 1×EC 50 Treatment group: Some spores showed obvious morphological abnormalities, manifested as spore collapse, wrinkling, and cell membrane invagination. Germinating germ tubes were generally abnormal, showing short, twisted, swollen, or producing numerous vacuoles, failing to extend normally. ≥2×EC 50In several treatment groups, the spore morphology was severely damaged. The vast majority of spores were severely shrunken and shriveled, losing their normal spindle shape, with their cell structure completely destroyed, leaving only spore remnants. The very few spores that were not shrunken also completely lost their ability to germinate.

[0044] This experiment showed that the concentration ≥2×EC 50 2-Heptanone not only persistently and completely inhibits the germination of *Anthracis chinensis* spores, but also directly destroys the cellular structure of the spores, leading to their irreversible death, exhibiting a sporicidal effect rather than simply a sporic inhibitory effect. Both physiological activity and ultrastructure confirm the potent control potential of 2-heptanone as a fumigant against the source of *Anthracis chinensis* infection in bananas.

[0045] Table 1. Effects of different concentrations of 2-heptanone on the germination rate of banana anthracnose spores

[0046]

[0047] Note: Different letters after the data in the same column indicate that the differences are significant at the p < 0.05 level.

[0048] Example 3: Inhibitory effect of 2-heptanone on colony growth

[0049] Methods: The plate-on-plate method was used to evaluate the volatile 2-heptanone at different concentrations (1×EC). 50 With 2×EC 50 The dynamic inhibitory effect of α on the growth of banana anthracnose pathogen was investigated. Colony diameter was measured periodically (0, 1, 3, 5, and 7 days), and the inhibition rate relative to the control group was calculated to analyze its antibacterial kinetic characteristics.

[0050] Results and Analysis: The results show that ( Figure 3 The antibacterial effect of 2-heptanone exhibits significant concentration-dependent and time-dynamic characteristics. 1×EC 50 The treatment group showed a sustained slowdown in growth throughout the observation period, with the inhibition rate peaking on day 3 (29.97±0.02%), then gradually declining to only 6.47±0.01% on day 7. This indicates that at this concentration, 2-heptanone mainly delayed growth and failed to completely inhibit latitudinal expansion. In contrast, 2×EC 50 The treatment group exhibited strong early inhibition and sustained retardation: the colony diameter hardly increased in the first 3 days (maintained at 0.8 cm), and the inhibition rate was as high as 86.28±0.00% on the 3rd day; although the colonies began to recover growth from the 5th day, their diameter (2.92±0.08 cm) was still much smaller than that of the control group by the 7th day, and the inhibition rate remained at a high level of 65.69±0.01%. This indicates that the high concentration of 2-heptanone produced a significant and sustained reversible inhibition of mycelial growth during the experimental period.

[0051] Based on previous spore-killing experiments, it is known that the antibacterial activity of 2-heptanone exhibits stage-specific lethality to spores and inhibitory effects on mycelial growth: at 2×EC 50 Concentrations of 2-heptanone at these concentrations can effectively kill spores, while its effect on established mycelium is primarily reversible growth inhibition. Therefore, 2-heptanone is more suitable for spore control during the disease prevention stage, rather than for treatment during the mycelial growth stage. This characteristic indicates that this substance is not suitable as the sole means of long-term preservation, but its highly effective short-term inhibitory ability makes it valuable in scenarios requiring preservation during critical window periods, such as post-harvest storage of fruits and vegetables and logistics transportation.

[0052] In summary, this experiment clarified that the antibacterial effect of 2-heptanone is time-dependent, concentration-dependent, and stage-specific, making it more suitable as an early preventative treatment or a short-term preservative. In actual production, it is recommended to use it for early prevention or in combination with agents that have long-lasting bactericidal effects and different properties to achieve a more sustained and stable disease management effect.

[0053] Example 4: Morphological observation of the destructive effect of 2-heptanone volatile gas on banana anthracnose mycelia.

[0054] Methods: Banana anthracnose fungal discs were inoculated into the center of PDA plates. The treatment group was co-cultured with a 2-heptanone volatile source in sealed Petri dishes, while the control group was kept away from volatile gases. All were cultured in the dark at 28°C. After the control group colonies had fully colonized the Petri dishes, high-resolution, multi-angle microscopic observation of the hyphae was performed using a KEYENCE VHX-6000 digital microscope system combined with a VHX-S650E free-angle observation system. The colony diameter was measured to assess the growth inhibition effect.

[0055] Results and Analysis: By comparing and analyzing the microscopic images of the two groups of samples, the effect of 2-heptanone on hyphal structure was evaluated. In the control group, hyphal growth was normal, characterized by uniform, smooth, naturally extending hyphae with vigorous branching. In the treatment group, however, significant abnormalities in hyphal morphology were observed, including obvious breakage, twisting, shrinkage, and localized cytoplasmic aggregation. Growth inhibition was assessed, with the colony diameter in the control group being 8.50±0.00 cm and in the treatment group being 2.73±0.08 cm, resulting in a growth inhibition rate of 67.84±0.01% (p<0.05).

[0056] The results showed that ( Figure 42-Heptanone significantly inhibited the macroscopic growth of banana anthracnose mycelia. In the control group, the mycelia were normal in morphology, smooth in surface, uniformly extended, and vigorously branched, while in the treated group, the mycelia showed obvious structural damage, including breakage, twisting, wrinkling, and cytoplasmic aggregation. Colony diameter measurements showed that the control group was 8.50±0.00 cm, while the treated group was 2.73±0.08 cm, with a growth inhibition rate of 67.84±0.01% (p < 0.05). Microscopic images clearly showed that the mycelia treated with 2-heptanone exhibited breakage and structural disintegration at a 500 μm scale. These results morphologically demonstrate that 2-heptanone can significantly inhibit the growth of banana anthracnose fungus by disrupting the mycelial morphology and structure, providing a morphological basis for controlling this disease using volatile substances.

[0057] Example 5: SEM observation of ultrastructural damage to mycelia and spores induced by volatile gases in *Bacillus anthracis* of banana.

[0058] Methods: To investigate the effects of volatile gases on the ultrastructure of pathogenic bacteria, scanning electron microscopy was used for observation. Colonies of *Anthracis bananais* that were significantly inhibited by QN2MO-1 volatile gases after 5 days of incubation (treatment group) and colonies that grew normally (control group) were used as samples.

[0059] Scanning electron microscopy (SEM) sample preparation:

[0060] Section fixation: Cut a 5 mm × 5 mm section of the bacteria from the edge of the colony and quickly immerse it in pre-cooled 2.5% glutaraldehyde phosphate buffer (0.1 mol / L, pH 7.2) and fix overnight at 4°C in the dark.

[0061] Rinsing: Rinse the sample three times with PBS phosphate buffer (0.1 mol / L, pH 7.2) of the same concentration, for 15 minutes each time.

[0062] Dehydration: The sample was dehydrated stepwise with a series of gradient ethanol (30%, 50%, 70%, 80%, 90%, 95%), each concentration for 15 minutes, followed by rinsing twice with 100% ethanol for 20 minutes each time.

[0063] Displacement and drying: The sample was eluted for 30 minutes with a mixture of ethanol and isoamyl acetate (1:1), followed by elution with 100% isoamyl acetate for 2 hours, and then dried using a critical point dryer.

[0064] Sputtering: The dried sample is attached to the sample stage, and an ion sputtering instrument is used to deposit a gold film with a thickness of about 10 nm on the sample surface.

[0065] Observation: The prepared samples were placed under a scanning electron microscope (GeminiSEM 460) and the ultrastructure morphology of hyphae and spores was observed and photographed under a suitable accelerating voltage.

[0066] Results and Analysis:

[0067] Scanning electron microscopy (SEM) observations revealed at the ultrastructural level that the volatile gases released by strain QN2MO-1 can directly disrupt the integrity of the cell wall, causing irreversible morphological distortion and structural disintegration of the hyphae and spores of *Anthracis bananais*, thus elucidating its strong destructive effect on the hyphae and spores of *Anthracis bananais* and clarifying its antibacterial and sporicidal mechanism.

[0068] Regarding hyphal morphology ( Figure 5 Compared with normal, plump, and smooth hyphae (Aa), the hyphae in the treatment group showed severe distortion; the hyphae collapsed and shriveled over a large area and became abnormally twisted (Ab); under high magnification, obvious local breaks, perforations (Ac) or spherical structures (Ad) were visible in the hyphae cell walls, indicating that the volatile gases severely damaged the integrity of the cell walls, thus losing their ability to infect.

[0069] Regarding spore morphology ( Figure 5 (B) The treated group spores were compared with normal spores that were regularly shaped, spindle-shaped, and had smooth surfaces. Figure 5 Compared to (a) in B: some spores show dense pits and erosion marks on their surface. Figure 5 In B of the text (b)); most spores are severely shrunken and deformed, losing their original structure ( Figure 5 In B of (c)); some spore cell walls were completely ruptured, leaving only fragments ( Figure 5 (d) in B).

[0070] Example 6: Determination of the broad-spectrum antibacterial activity of 2-heptanone volatile gases

[0071] Methods: To evaluate the broad-spectrum antibacterial activity of 2-heptanone, ten common plant pathogens covering postharvest diseases, foliar diseases, and soil-borne diseases of fruits were selected for testing. Information on the tested pathogens is shown in Table 2.

[0072] Table 2. List of pathogenic fungi of tested plants

[0073]

[0074] In the experiment, a filter paper with 50 μL of 2-heptanone (analytical grade) was placed in the center of the sealed petri dish lid, with sterile water as a control. PDA plates inoculated with bacterial discs of different pathogens were inverted and sealed, and incubated at 28°C. Once the colonies in the control group reached a suitable size, the colony diameter of each treatment group was measured, and the inhibition rate was calculated. Each treatment was repeated three times.

[0075] Results and Analysis: The volatile gas of 2-heptanone showed varying degrees of inhibitory effects on all 10 tested plant pathogens, demonstrating its great application potential as a broad-spectrum fumigant. Figure 6 ).

[0076] Based on their antibacterial rate, their activity can be divided into three levels:

[0077] Strong inhibition (inhibition rate >80%): 2-Heptanone has a very significant inhibitory effect on litchi anthracnose fungus and strawberry anthracnose fungus, with inhibition rates as high as 90.59% and 90.78% respectively, indicating that it has excellent control potential against a variety of postharvest diseases of fruits caused by different anthracnose fungi.

[0078] Moderate inhibition (inhibition rate 50%-70%): 2-Heptanone showed moderate inhibitory effects against *Anthracnose causal agent* of papaya (64.51%), *Root rot causal agent* of corn (59.22%), *Fusarium wilt causal agent* of tomato (53.73%), *Fusarium wilt causal agent* of banana (54.90%), and *Anthracnose causal agent* of banana (54.12%). Notably, it also showed clear activity against the pathogens of various soil-borne diseases (such as *Fusarium wilt causal agent* of tomato and banana), which greatly broadened its application scope.

[0079] Weak inhibition (inhibition rate <50%): The inhibitory effect on mango leaf blight fungus (51.76%), wheat scab fungus (36.67%) and mango anthracnose fungus (41.37%) was relatively weak, but its inhibition rate still exceeded 35%, indicating that 2-heptanone gas still has a certain interference effect on these pathogens.

[0080] Comprehensive analysis shows that 2-heptanone exhibits significant fumigation inhibitory activity against a variety of important pathogens belonging to the genera *Colletotrichum* and *Fusarium*. This broad-spectrum characteristic implies that fumigants developed based on 2-heptanone hold promise for controlling complex diseases caused by multiple pathogens, or for integrated control of different crop diseases in crop rotation systems, demonstrating significant development value.

Claims

1. Use of 2-heptanone in inhibiting Mycosphaerella fijiensis in banana anthracnose Colletotrichum musae .

2. Use according to claim 1, characterized in that, The 2-heptanone exerts a fumigating effect in the form of a gas.

3. Use according to claim 2, characterized in that, The 2-heptanone exerts an inhibiting effect by inhibiting spore germination or mycelium growth of the banana anthracnose fungus.

4. Use of 2-heptanone for the preparation of a fumigant for inhibiting phytopathogenic fungi, characterized in that, The plant pathogenic fungus is the banana anthracnose fungus.

5. Use of a fumigant in inhibiting the growth of Colletotrichum musae, characterized in that, The active ingredient of the fumigant is 2-heptanone.

6. A non-contact fumigation method for inhibiting a plant pathogenic fungus, characterized by, In a closed or semi-closed space, the fumigant in the application of claim 5 is applied to form a 2-heptanone gas environment with bacteriostatic activity in the space, thereby inhibiting the growth of a plant pathogenic fungus in the space; the plant pathogenic fungus is the banana anthracnose fungus.

7. The non-contact fumigation method of claim 6, wherein, The effective application dose of the 2-heptanone is 0.05-8.00 mL / L in terms of unit volume of the space. The 2-heptanone exerts a fumigating effect in the form of a gas. The 2-heptanone exerts an inhibiting effect by inhibiting spore germination or mycelium growth of the banana anthracnose fungus. The plant pathogenic fungus is the banana anthracnose fungus. The active ingredient of the fumigant is 2-heptanone. In a closed or semi-closed space, the fumigant in the application of claim 5 is applied to form a 2-heptanone gas environment with bacteriostatic activity in the space, thereby inhibiting the growth of a plant pathogenic fungus in the space; the plant pathogenic fungus is the banana anthracnose fungus. The effective application dose of the 2-heptanone is 0.05-8.00 mL / L in terms of unit volume of the space.

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