A composition and method for controlling mango rapid death disease

Abstract

This invention relates to the technical field of microbial disease control, specifically to a composition and method for controlling mango rapid death disease. The composition comprises, by weight percentage: 0.05%–0.5% polyamine mixture, 1.0%–10.0% *Lactobacillus plantarum* component, 0.01%–0.2% stabilizer, 0.1%–2.0% penetration enhancer, 1.0%–5.0% slow-release carrier, 0.05%–0.5% pH adjuster, and a carrier or diluent to bring the total to 100%. The mass ratio of polyamine to *Lactobacillus plantarum* component is 10:1 to 100:1. This composition is applied to mango plants through root irrigation or soil pinhole injection, effectively inhibiting... Fusarium The pathogenic fungus activates systemic resistance in plants and rebuilds the rhizosphere microecology. Field trial results show that the composition of this invention significantly reduces the incidence of disease, enhances root vitality and plant growth rate, and is superior to existing commercially available control agents. It is suitable for the promotion and use of green agricultural disease control.

Description

Technical Field

[0001] This invention relates to the technical field of microbial disease control, specifically to a composition and method for controlling mango rapid death disease. Background Technology

[0002] Mango (Mangifera indica L.) is one of the most important fruit trees widely cultivated in tropical and subtropical regions, possessing high economic and nutritional value. However, with the expansion of planting area and changes in climate conditions, mangoes face various disease threats during production, among which "mango rapid death disease" (also known as mango acute wilt or mango damping-off) is a devastating disease.

[0003] The main pathogens of mango rapid death disease are fungi of the genus *Fusarium*, especially *Fusarium oxysporum* and *Fusarium fujikuroi*. These pathogens invade the vascular system of the plant through the roots, causing blockage of the xylem vessels and obstruction of water transport. This ultimately leads to symptoms such as sudden wilting and shedding of leaves, and death of the entire plant. The disease progresses rapidly, spreads widely, and has a short incubation period, making it difficult to control and often causing large-scale yield reductions or even total crop failure in orchards.

[0004] Currently, the main methods for controlling mango rapid death disease include agronomic management, chemical control, and grafting with disease-resistant rootstocks. In terms of agronomic management, crop rotation, removal of diseased plant debris, and improved soil permeability can reduce disease incidence to some extent. Chemical control mainly involves applying fungicides (such as carbendazim and difenoconazole) for soil treatment or root drenching; however, long-term application may lead to pathogen resistance and poses a risk of pesticide residues. While the application of disease-resistant rootstocks can effectively control the disease, their adaptability and propagation efficiency remain limited. Furthermore, current control measures generally only address the symptoms and not the root cause, lacking long-term effectiveness, and a highly efficient, safe, green, and sustainable integrated control technology is still lacking.

[0005] Therefore, there is an urgent need to provide a new prevention and control method for mango rapid death disease. This method should have the advantages of being easy to operate, combining prevention and treatment, and being environmentally friendly. It should cut off the disease transmission route at the source and improve the disease resistance of mango plants to ensure the sustainable and healthy development of the mango industry. Summary of the Invention

[0006] To address the above problems, the present invention aims to provide a composition for preventing and controlling mango rapid death disease, comprising the following components by weight percentage:

[0007] A polyamine mixture, comprising one or a combination of putrescine, spermidine, and spermine, in a content of 0.05% to 0.5%;

[0008] The *Lactobacillus plantarum* component is selected from *Lactobacillus plantarum* cells, *Lactobacillus plantarum* supernatant, or *Lactobacillus plantarum* supernatant lyophilized powder, and its content is 1.0% to 10.0%.

[0009] The stabilizer is selected from sodium ascorbate, glutathione, or a combination thereof, and its content is 0.01% to 0.2%.

[0010] The penetration enhancer is selected from mannitol, polyethylene glycol, or a combination thereof, and its content is 0.1% to 2.0%.

[0011] The sustained-release carrier is selected from sodium alginate, gelatin, or a combination thereof, with a content of 1.0% to 5.0%.

[0012] pH adjuster, selected from sodium citrate, sodium acetate or a combination thereof, with a content of 0.05% to 0.5%;

[0013] The carrier or diluent, selected from sterile physiological saline, sterile deionized water, maltodextrin, or soluble starch, is used to bring the total to 100%.

[0014] The mass ratio of polyamines to Lactobacillus plantarum components is 10:1 to 100:1.

[0015] In a preferred embodiment, the *Lactobacillus plantarum* component is selected from one of the following:

[0016] a. Lactobacillus plantarum cells: These are Lactobacillus plantarum cells precipitated after washing with physiological saline, with a mass percentage of 1% to 5%;

[0017] b. Supernatant of Lactobacillus plantarum: a sterile liquid obtained by centrifugation and filtration of Lactobacillus plantarum after culture, with a mass percentage of 3% to 10%;

[0018] c. Lyophilized supernatant of Lactobacillus plantarum: The powder obtained by freeze-drying the supernatant, with a mass percentage of 1% to 3%.

[0019] In a preferred embodiment, the polyamine is a combination of putrescine, spermidine, and spermine, wherein putrescine accounts for 20% to 70% of the total mass of the polyamine, spermidine accounts for 30% to 50%, and spermine accounts for 10% to 50%.

[0020] In a preferred embodiment, the method for preparing the lyophilized powder of Lactobacillus plantarum supernatant includes the following steps:

[0021] S1. Propagation: Take 2% glycerol inoculum and inoculate it into MRS liquid medium. After sterilization and cooling, ferment in an incubator at 35℃ for 22 hours.

[0022] S2. Centrifugation; After the expansion culture is completed, centrifuge at 10000 rpm at 0℃ for 10 minutes, take the cell supernatant to obtain the original supernatant of Lactobacillus plantarum.

[0023] S3. Freeze-drying: Place the supernatant of Lactobacillus plantarum into a freeze-drying oven and freeze-dry for 4 hours to obtain freeze-dried powder of Lactobacillus plantarum supernatant.

[0024] In a preferred embodiment, in step S2, the original supernatant of *Lactobacillus plantarum* is filtered through a 0.22 μm sterile filter membrane to remove bacteria, thereby obtaining *Lactobacillus plantarum* supernatant.

[0025] In a preferred embodiment, after separating the Lactobacillus plantarum cell precipitate obtained in step S2 from the bacterial solution, it is washed with 0.81% physiological saline to obtain the Lactobacillus plantarum cell precipitate.

[0026] The present invention also provides the application of the composition for preventing mango rapid death disease in the prevention and control of mango rapid death disease.

[0027] The present invention also provides a method for preventing and controlling mango rapid death disease, which is achieved by applying the composition for preventing and controlling mango rapid death disease to the roots of mango plants.

[0028] In a preferred embodiment, the method of applying the composition to the roots of the mango plant is irrigation.

[0029] In a preferred embodiment, the method of applying the composition to the roots of the mango plant is soil pinhole injection.

[0030] The beneficial effects of this invention are as follows:

[0031] This invention provides a composition for preventing and controlling mango rapid death disease. By scientifically combining natural polyamines with *Lactobacillus plantarum* cells or their metabolites, and supplementing with various biocompatible components such as stabilizers, penetration enhancers, slow-release carriers, and pH adjusters, it achieves highly efficient control of mango rapid death disease and has the following beneficial effects:

[0032] 1. Green and safe, in line with the development direction of ecological agriculture: This invention does not rely on chemical bactericides, but uses polyamines and lactic acid bacteria metabolites as the main active ingredients. They are naturally derived, degrade well, and have no residual pollution to the environment, which fully meets the basic requirements of modern green agriculture, sustainable planting and food safety supervision.

[0033] 2. Multiple mechanisms and synergistic control effects: Polyamine components can induce systemic resistance in plants, strengthen the structure of rhizosphere cell walls, and improve the plant's self-defense capabilities; Lactobacillus plantarum and its metabolites have the effects of antagonizing fungi and regulating rhizosphere microecology. The two work together to exert a compound control mechanism of "inducing resistance + inhibiting bacteria + protecting roots", which significantly reduces the incidence and mortality of mango rapid death disease.

[0034] 3. Long-lasting effect and high sustained-release stability: By introducing natural sustained-release carriers such as sodium alginate or gelatin, the active ingredients are released stably in the soil environment, prolonging the action period and reducing the frequency of application; at the same time, the use of stabilizers can prevent polyamine degradation and ensure the activity of the composition is maintained during storage and use.

[0035] In summary, this invention integrates natural polyamines and lactic acid bacteria fermentation products to construct a green, safe, efficient, and easy-to-operate mango rapid death disease control system. It has both good disease inhibition effect and environmental friendliness, making it particularly suitable for green pest control applications in modern orchards. It has broad promotional value and industrialization prospects. Attached Figure Description

[0036] Figure 1 This is a schematic diagram illustrating the control effect (incidence rate) of the composition of the present invention on mango rapid death disease;

[0037] Figure 2 This is a schematic diagram illustrating the control effect (root vigor score) of the composition of the present invention on mango rapid death disease;

[0038] Figure 3 This is a schematic diagram showing the control effect of the composition of the present invention on mango rapid death disease (average plant height increase in 28 days). Detailed Implementation

[0039] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0040] Implementation Group 1 (T1)

[0041] This embodiment provides a composition for preventing and controlling mango rapid death disease, comprising the following components by weight percentage:

[0042] Polyamine mixture (composed of putrescine, spermidine, and spermine): 0.30%, of which: putrescine accounts for 50% of the total polyamine, i.e., 0.15%; spermidine accounts for 30% of the total polyamine, i.e., 0.09%; and spermine accounts for 20% of the total polyamine, i.e., 0.06%.

[0043] Lyophilized supernatant powder of Lactobacillus plantarum: 2.50%, prepared from Lactobacillus plantarum through the following steps:

[0044] S1. Take the Lactobacillus plantarum inoculum preserved with 2% glycerol and inoculate it into MRS liquid medium. After autoclaving at 121℃ for 15 minutes, cool it to room temperature and then culture it at 35℃ with shaking for 22 hours.

[0045] S2. Centrifuge the fermentation broth at 10,000 rpm for 10 minutes (0℃) and collect the supernatant;

[0046] S3. After sterilizing the obtained supernatant through a 0.22 μm sterile filter membrane, place it in a freeze-drying oven and freeze-dry at −50℃ for 4 hours to obtain freeze-dried powder of Lactobacillus plantarum supernatant;

[0047] Stabilizer (sodium ascorbate): 0.10%;

[0048] Penetration enhancer (mannitol): 1.00%;

[0049] Sustained-release carrier (sodium alginate): 3.00%;

[0050] pH adjuster (sodium citrate): 0.20%;

[0051] Carrier diluent (sterile saline): 92.90%, used to bring the total volume to 100%.

[0052] Before use, this composition is prepared as a liquid working solution. When using it, it is applied to the roots of the mango tree in undiluted form. The amount of liquid applied to each mango tree is 250 mL. Apply it 1 to 2 times consecutively, with an interval of 7 days.

[0053] Implementation Group 2 (T2)

[0054] This embodiment provides a composition for preventing and controlling mango rapid death disease, which, by weight percentage, comprises the following components:

[0055] Polyamine mixture (composed of putrescine, spermidine, and spermine): 0.10%, of which: putrescine accounts for 40% of the total polyamines, i.e., 0.04%; spermidine accounts for 40% of the total polyamines, i.e., 0.04%.

[0056] Spermine accounts for 20% of the total polyamines, which is 0.02%.

[0057] Lactobacillus plantarum supernatant: 8.00%, its preparation method includes:

[0058] S1. Inoculate 2% Lactobacillus plantarum glycerol preservation solution into MRS liquid medium, sterilize at 121℃ for 15 minutes, cool, and let ferment at 35℃ for 24 hours.

[0059] S2. After fermentation is complete, centrifuge at 10,000 rpm for 10 minutes (0℃) to separate the bacterial cells;

[0060] S3. The supernatant is filtered through a 0.22 μm sterile filter membrane to obtain sterile lactobacillus supernatant, which can be used directly for the preparation of the composition.

[0061] Stabilizer (glutathione): 0.05%;

[0062] Penetration enhancer (polyethylene glycol 400): 0.50%;

[0063] Sustained-release carrier (gelatin): 1.50%;

[0064] pH adjuster (sodium acetate): 0.30%;

[0065] Carrier diluent (sterile deionized water): 89.55%, bring to total 100%.

[0066] After preparation, the composition is placed in a sealed container and stored at 4°C. No dilution is required before use. It is applied to the root zone of mango trees by soil pinhole injection, with a dosage of 150 mL per tree and 2-3 injection points per injection. It is suitable for rapid and targeted control of rapid death disease in high-density planting environments in orchards.

[0067] Implementation Group 3 (T3)

[0068] This embodiment provides a composition for preventing and controlling mango rapid death disease, which, by weight percentage, comprises the following components:

[0069] Polyamine mixture (combination of putrescine, spermidine, and spermine): 0.45%, of which: putrescine accounts for 60% of the total polyamines, i.e., 0.27%; spermidine accounts for 30% of the total polyamines, i.e., 0.135%; and spermine accounts for 10% of the total polyamines, i.e., 0.045%.

[0070] Lactobacillus plantarum cells: 4.0%, prepared as follows:

[0071] Lactobacillus plantarum was cultured in MRS liquid medium at 35°C with constant shaking for 20 hours.

[0072] After the culture is completed, centrifuge at 10,000 rpm at 0℃ for 10 minutes and discard the supernatant;

[0073] The resulting precipitate was washed twice with 0.81% sterile physiological saline to obtain Lactobacillus plantarum cell precipitate;

[0074] Stabilizer (sodium ascorbate and glutathione in a 1:1 ratio): 0.15%;

[0075] Penetration enhancer (mannitol and polyethylene glycol compound): 1.5%;

[0076] Sustained-release carrier (sodium alginate): 5.0%;

[0077] pH adjuster (sodium citrate): 0.20%;

[0078] Carrier diluent (sterile deionized water): 88.70%, bring to 100%.

[0079] The composition, after formulation, forms a milky white homogeneous liquid preparation that does not require secondary dilution before use. Application is via conventional root irrigation in orchards. Use 300 mL of the composition per mango tree, combined with regular irrigation, for two consecutive applications, with an interval of 7-10 days.

[0080] Implementation Group 4 (T4)

[0081] This embodiment provides a composition for preventing and controlling mango rapid death disease, which, by weight percentage, comprises the following components:

[0082] Polyamine mixture (combination of putrescine, spermidine, and spermine): 0.20%, wherein: putrescine accounts for 30% of the total polyamines, i.e., 0.06%; spermidine accounts for 50% of the total polyamines, i.e., 0.10%; and spermine accounts for 20% of the total polyamines, i.e., 0.04%.

[0083] Lyophilized powder of Lactobacillus plantarum supernatant: 1.50%, prepared by the following method:

[0084] S1. Take the Lactobacillus plantarum culture solution preserved with 2% glycerol and inoculate it into MRS liquid medium. After autoclaving at 121℃, cool it to room temperature and culture it with shaking at 35℃ for 22 hours.

[0085] S2. After fermentation, centrifuge at 10,000 rpm and 0℃ for 10 minutes to separate the supernatant;

[0086] S3. After filtering the supernatant through a 0.22 μm sterile filter membrane, it was freeze-dried at −50℃ for 4 hours to obtain freeze-dried powder of Lactobacillus plantarum supernatant.

[0087] Stabilizer (glutathione): 0.02%;

[0088] Penetration enhancer (polyethylene glycol 400): 0.8%;

[0089] Sustained-release carrier (gelatin): 2.0%;

[0090] pH adjuster (sodium acetate): 0.10%;

[0091] Carrier diluent (maltodextrin): 95.38%, used to bring the total mass to 100%.

[0092] The composition is a powder formulation. When using, it should be dissolved in water at a ratio of 1:100 by mass to prepare a working solution. It is applied at fixed points in the root zone of the orchard using a drip irrigation system. The initial application is 200 mL of working solution per tree, and the application is repeated every 10 days.

[0093] Control group 1 (C1)

[0094] To verify the scientific validity and rationality of the parameter ranges of each component in the composition of the present invention, the following comparative example (C1) was set up for comparative experiments:

[0095] The components and formulation of this composition are as follows, by mass percentage:

[0096] Polyamine mixture (a combination of putrescine, spermidine, and spermine): 1.2%, of which: putrescine accounts for 60% of the total polyamines, i.e., 0.72%; spermidine accounts for 30%, i.e., 0.36%; and spermine accounts for 10%, i.e., 0.12%.

[0097] Lyophilized supernatant of Lactobacillus plantarum: 0.3%;

[0098] Stabilizer (sodium ascorbate): 0.02%;

[0099] Penetration enhancer (PEG-400): 0.5%;

[0100] Sustained-release carrier (gelatin): 1.0%;

[0101] pH adjuster (sodium citrate): 0.1%;

[0102] Carrier diluent (sterile water): 96.88%, bring to 100% of total mass.

[0103] Application method: Apply to mango trees in the early stages of rapid death disease using the conventional root irrigation method. The dosage is 250 mL per tree, and the treatment is repeated twice with an interval of 7 days.

[0104] Control group 2 (C2)

[0105] To verify the scientific validity and rationality of the parameter ranges of each component in the composition of the present invention, the following comparative example (C2) was set up for comparative experiments:

[0106] The composition comprises the following components by weight percentage:

[0107] Polyamine mixture (combination of putrescine, spermidine, and spermine): 0.25%, of which: putrescine accounts for 40%, or 0.10%; spermidine accounts for 40%, or 0.10%; and spermine accounts for 20%, or 0.05%.

[0108] Lactobacillus plantarum cell precipitation: 15.0%;

[0109] Penetration enhancer (PEG-400): 0.8%;

[0110] pH adjuster (sodium citrate): 0.1%;

[0111] Carrier diluent (sterile water): 83.85%, bring to 100% of total mass.

[0112] Application method: Apply the composition directly to the roots of mango trees by irrigation, using 250 mL per plant, and repeat the treatment twice, with an interval of 7 days.

[0113] Control group 3 (C3)

[0114] To verify the efficacy of the composition of the present invention, comparative example C3 was constructed using existing compound formulations:

[0115] The control composition selected in this comparative example is a combination of commonly used soil-borne disease control agents, including:

[0116] Carbendazim wettable powder (80%): Dilute 800 times the recommended concentration;

[0117] Chlorobromoisocyanuric acid (90% available chlorine): Dilute 1000 times the recommended concentration;

[0118] The method of application is to alternate the two agents for root irrigation, with an application cycle of once every 10 days, for two consecutive times;

[0119] The total amount of liquid pesticide applied to each mango tree is 250 mL.

[0120] Control group 4 (C4)

[0121] To verify the efficacy of the composition of the present invention, comparative example C4 was constructed using existing compound formulations:

[0122] Kasugamycin soluble powder (10% active ingredient): used to inhibit Gram-positive bacteria and some fungi, diluted 600 times;

[0123] Amino acid foliar nutrient solution: Contains 20% amino acids and trace element complex, diluted 300 times.

[0124] The treatment method is to mix the two in a 1:1 ratio and apply the mixture to the roots by drenching, with a dosage of 300 mL per mango tree;

[0125] Apply once every 7 days, for a total of 2 treatments.

[0126] Comparative experiment

[0127] Experimental Objective

[0128] The efficacy of the mango rapid death disease control composition provided by this invention under different formulations and application conditions was verified, and its differences from commercially available agents and conventional methods were evaluated, further demonstrating the green and safe advantages and application value of this invention.

[0129] Experimental materials

[0130] Experimental plants: 180 mango seedlings (approximately 40 cm in height, with normal leaf development and free from disease);

[0131] Inoculation source of pathogen: Fusarium oxysporum, activated by PDA culture before use;

[0132] Experimental groups: as shown in Table 1:

[0133] Table 1 Comparative Experiment Groups

[0134]

[0135] Inoculation and treatment methods

[0136] Inoculation method: On day 1 of the experiment, all groups inoculated with pathogen suspension were inoculated into the rhizosphere soil. 10 mL of F. oxysporum spore suspension (concentration approximately 10) was dripped onto the roots of each mango plant. 6 (CFU / mL)

[0137] First treatment: Apply the treatment solution 250 mL per plant 24 hours after inoculation;

[0138] Second treatment: Repeat the same treatment after a 7-day interval;

[0139] Treatment period: The total observation period was 28 days, during which the greenhouse was kept at a constant temperature, the soil was kept moist, and there was sufficient light.

[0140] Observation and recording indicators

[0141] Disease incidence statistics: The number of diseased plants in each group was recorded every 7 days, and the diagnosis was based on typical rapid death symptoms (leaf wilting, leaf drop, and stem softening).

[0142] Root vitality score: 28-day end-stage root washing observation, scoring criteria (0-5 points);

[0143] Plant height variation: Record the initial and final height of each plant to assess growth differences.

[0144] The root vitality score uses a 0-5 point scale, with scoring dimensions including root color, root hair quantity, taproot integrity, and the proportion of newly grown white roots. The specific scoring criteria are shown in Table 2.

[0145] Table 2 Root Vigor Scoring Criteria

[0146]

[0147] The comparative experimental results are shown in Table 3:

[0148] Table 3 Comparison of experimental results data

[0149]

[0150] Based on Table 3, draw a chart, such as Figure 1 , Figure 2 , Figure 3 As shown

[0151] Data Analysis Conclusions

[0152] This comparative experiment focused on the control effect of mango rapid death disease. Four implementation groups of this invention were set up and systematically compared with the parameter exceeding limit group (C1, C2) and the existing commercially available agent combination group (C3, C4). The control effect and the scientific validity of the formulation were evaluated using indicators such as disease incidence, root vigor score, and average plant height increase. The experimental results showed that:

[0153] 1. The composition of the present invention exhibits stable and excellent efficacy, significantly superior to the comparative group.

[0154] The incidence rate in groups 1–4 was controlled at 19.0%–25.3%, significantly lower than that in the control group.

[0155] The incidence of C1 (severe polyamine overdose + low lactobacillus levels) reached 47.6%;

[0156] The incidence of C2 (excessive use of Lactobacillus) was 44.3%;

[0157] C3 (carbendazim + chlorobromoisocyanuric acid) was 41.2%;

[0158] C4 (kasugamycin + amino acid nutrient solution) is 43.5%.

[0159] This indicates that the ratio of polyamines to lactobacilli within the component range set in this invention has a clear effective threshold and synergistic window for prevention and control. Exceeding the limit or being unbalanced will significantly reduce the prevention and control effect.

[0160] 2. The composition of this invention provides optimal root system recovery and possesses the advantage of "nourishing roots and promoting growth".

[0161] The root system score of the experimental group was 4.0-4.5, which was close to that of the healthy control group B (4.8);

[0162] The control group C1 (lacking effective lactic acid bacteria and without slow release) had a root score of only 3.1, and showed root yellowing and absorption disorders.

[0163] The C2 (excess lactobacillus) score is 3.3, which is characterized by root flocculation and bacterial aggregation, resulting in decreased soil aeration.

[0164] C3 and C4 were 3.2 and 3.3 respectively, indicating some pesticide damage or microecological disruption, making it difficult to restore rhizosphere health.

[0165] The addition of appropriate amounts of stabilizers, slow-release carriers, and penetration enhancers to the composition of this invention enhances the stable release and absorption efficiency of the active ingredients, providing a good foundation for root recovery.

[0166] 3. The growth-promoting effect in the treatment group was significant, and considerably better than that in the control group.

[0167] The average increase in length in the experimental group was 9.8–11.2 cm, which was significantly higher than that in C1 (6.9 cm), C2 (7.3 cm), C3 (7.1 cm), and C4 (7.4 cm).

[0168] The "inducing resistance + antibacterial + root-nourishing" mechanism of the composition of this invention enables mango trees to maintain good growth vigor even under disease stress;

[0169] Although the comparative combination contained some nutrient components (such as C4), the overall growth of the plants was still inhibited because the disease was not effectively controlled.

[0170] 4. Parameter deviations and component imbalances verify the rationality of the scope of this invention.

[0171] The amount of polyamine in C1 exceeded the upper limit of this invention by more than 2 times, which triggered plant stress, manifested as leaf curling and root shrinkage.

[0172] The content of Lactobacillus in C2 is much higher than the upper limit of this invention, which leads to bacterial aggregation and limited oxygen utilization in the root zone.

[0173] Although C3 and C4 are commercially available combinations, they lack targeting, have unstable efficacy, and pose high ecological risks.

[0174] These results demonstrate that the component types and proportion ranges clearly defined in this invention are the key technological foundation for achieving the triple goals of disease prevention, injury prevention, and growth promotion, and possess sufficient scientific validity and practical effectiveness.

[0175] Summarize:

[0176] Compared with the C1-C4 comparative examples, the composition of this invention for controlling mango rapid death disease shows more outstanding performance in terms of disease prevention effect, root recovery, growth promotion and ecological safety. The parameter control is scientific and reasonable, and the formula structure is synergistic and efficient. It is a green, efficient, low-toxicity and sustainable new plant protection solution, which is particularly suitable for tropical orchard environments where rapid death disease is prevalent, and has broad prospects for promotion and application.

[0177] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composition for controlling mango sudden death, characterized by, by mass percentage, comprising the following components: a polyamine mixture comprising one or a combination of putrescine, spermidine, and spermine in an amount of 0.05% to 0.5%; a Lactobacillus plantarum component selected from one of Lactobacillus plantarum cell precipitate, Lactobacillus plantarum supernatant, or Lactobacillus plantarum supernatant freeze-dried powder in an amount of 1.0% to 10.0%; a stabilizer selected from sodium ascorbate, glutathione, or a combination thereof in an amount of 0.01% to 0.2%; a penetration enhancer selected from mannitol, polyethylene glycol, or a combination thereof in an amount of 0.1% to 2.0%; a sustained-release carrier selected from sodium alginate, gelatin, or a combination thereof in an amount of 1.0% to 5.0%; a pH regulator selected from sodium citrate, sodium acetate, or a combination thereof in an amount of 0.05% to 0.5%; a carrier or diluent selected from sterile normal saline, sterilized deionized water, malt dextrin, or soluble starch for making up to 100%; wherein the mass ratio of the polyamine to the Lactobacillus plantarum component is 10:1 to 100:

1.

2. A composition for controlling mango sudden death according to claim 1, characterized by, The Lactobacillus plantarum component is selected from one of the following: a. Lactobacillus plantarum cell precipitate: Lactobacillus plantarum cell precipitate after washing with normal saline, in an amount of 1% to 5% by mass percentage; b. Lactobacillus plantarum supernatant: sterile liquid obtained by centrifugation and filtration through a filter membrane after culturing Lactobacillus plantarum, in an amount of 3% to 10% by mass percentage; c. Lactobacillus plantarum supernatant freeze-dried powder: powder obtained by freeze-drying the supernatant, in an amount of 1% to 3% by mass percentage.

3. The composition for preventing and treating mango sudden death according to claim 1, wherein the polyamine is a combination of putrescine, spermidine, and spermine, wherein the mass percentage of putrescine in the total amount of polyamine is 20% to 60%, the mass percentage of spermidine is 30% to 50%, and the mass percentage of spermine is 10% to 50%. The preparation method of the Lactobacillus plantarum supernatant freeze-dried powder comprises the following steps:

4. A composition for controlling mango sudden death according to claim 2, characterized by, S1, expansion culture: 2% glycerol seed liquid is inoculated into MRS liquid medium, sterilized and cooled, and then fermented in a 35°C incubator for 22 hours; S2, centrifugation: after the expansion culture is completed, centrifugation is performed at 10,000 rpm and 0°C for 10 minutes, the cell supernatant is taken, and the Lactobacillus plantarum supernatant stock solution is obtained. The Lactobacillus plantarum supernatant stock solution is filtered through a 0.22 μm sterile filter membrane to remove the bacteria, and the Lactobacillus plantarum supernatant is obtained; S3, freeze-drying: the Lactobacillus plantarum supernatant is placed in a freeze-drying box for freeze-drying for 4 hours, and the Lactobacillus plantarum supernatant freeze-dried powder is obtained. The method is achieved by applying the composition for preventing and treating mango sudden death according to any one of claims 1 to 4 to the roots of mango plants.

5. A method for controlling sudden death syndrome, characterized by, The method of applying the composition to the roots of mango plants is irrigation.

6. A method for controlling sudden death syndrome according to claim 5, wherein, The method of applying the composition to the roots of mango plants is soil needle injection.

7. A method for controlling sudden death syndrome according to claim 6, wherein 8. Use of the composition for preventing and treating mango sudden death according to any one of claims 1 to 6 in preventing and treating mango sudden death. ​

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