Methods for preventing fruit rust in banana cultivation and compound fertilizer compositions

Abstract

This invention discloses a method for preventing russeting in banana cultivation, belonging to the field of banana cultivation technology. Addressing the problems of nutrient imbalance caused by fixed fertilization, short-lasting foliar protection, and high incidence of russeting due to weak peel cell walls in existing technologies, this invention proposes a phased application of a specific ratio of compound fertilizer from the early budding stage to harvest: For the roots, a first fertilizer with a 30:10:10 nitrogen-phosphorus-potassium ratio is applied alternately with a second fertilizer with a 5:5:45 ratio, simultaneously supplemented with potassium chloride and amino acid liquid organic fertilizer to replenish micronutrients; during key growth stages, a mixture of a third and fourth fertilizer containing high calcium, humic acid, and seaweed extract is sprayed, with synergistic effects of 750-fold and 1500-fold dilutions enhancing peel resistance. This method, through dynamic nutrient regulation and synergistic foliar protection, significantly improves peel firmness and effectively reduces the incidence of russeting, making it suitable for improving fruit quality and ensuring commercial value in major tropical and subtropical banana-producing areas.

Description

Technical Field

[0001] This invention belongs to the field of banana planting technology, specifically a method for preventing fruit rust in banana planting and a compound fertilizer composition. Background Technology

[0002] Fruit rust is one of the main problems affecting fruit quality in banana cultivation, especially in areas with high temperature and humidity. Current techniques mainly rely on chemical fungicides and fixed-ratio fertilization, but these still have the following problems and shortcomings:

[0003] Traditional fertilization often uses fixed-ratio compound fertilizers, failing to adjust the nitrogen, phosphorus, and potassium ratios according to the different growth stages of bananas (budding, fruit expansion, and ripening). The budding stage requires higher nitrogen to promote stem and leaf growth, while the fruit expansion stage requires higher potassium to improve fruit quality. A fixed ratio easily leads to nutrient imbalance: excess potassium during budding inhibits nitrogen absorption, while excessive nitrogen during fruit expansion delays ripening. Furthermore, insufficient supplementation of secondary elements such as calcium and magnesium results in weak cell walls in the fruit peel, making it susceptible to fungal infections and the formation of rust spots.

[0004] Conventional foliar sprays of fungicides (such as difenoconazole) or nutrient solutions (such as calcium fertilizer) are easily washed away by rain or decomposed by ultraviolet light, and their effective period is usually ≤3 days, requiring frequent spraying (1-2 times per week), increasing labor costs. Some growers add adjuvants (such as organosilicon) to prolong the effect, but this may clog the spray nozzle or damage the waxy layer on the fruit surface, exacerbating fruit russeting.

[0005] Long-term, single-use application of chemical fertilizers leads to soil acidification (pH < 5.5) or salinization (EC value > 2.0 mS / cm), inhibiting the activity of beneficial microorganisms (such as phosphate-solubilizing bacteria and nitrogen-fixing bacteria), and causing the soil organic matter content to decline year by year (≤ 1.5%). Insufficient microbial activity further reduces nitrogen fertilizer utilization (only 50%-60%), and unabsorbed nitrogen is lost through leaching or volatilization, exacerbating environmental pollution.

[0006] High temperatures (≥30℃) and high humidity (≥80%) accelerate the spread of rust spores and weaken plant resistance. Traditional treatments lack environmental response mechanisms and cannot dynamically adjust drug release rates in response to sudden changes in weather conditions, resulting in delayed protection. Furthermore, at high temperatures, some fungicides (such as carbendazim) undergo accelerated photodegradation, leading to a rapid decrease in the concentration of active ingredients and a sharp reduction in disease control efficacy.

[0007] Current foliar spraying technologies mostly use liquid pesticides directly, lacking slow-release carrier designs, resulting in low pesticide utilization. Although some studies have attempted to use nanocarriers (such as silica microspheres), these are costly and have poor biodegradability, potentially causing microplastic pollution.

[0008] The reasons for these long-standing problems include: the long banana growth cycle (6-8 months) requires frequent adjustments to fertilizer formulations, and traditional methods struggle to precisely match the needs of each stage, easily leading to nutrient waste or deficiency. Foliar disease control needs to balance fungicide application, nutrient supplementation, and stress induction; single-component formulations cannot achieve multiple effects, while multi-component mixtures are prone to antagonism or precipitation. The lack of real-time monitoring and response to environmental factors such as temperature and humidity prevents "on-demand" drug release, resulting in poor disease control stability under extreme climates. Developing low-cost, biodegradable carrier materials is challenging, requiring a balance between drug loading, slow-release performance, and environmental compatibility, which existing carriers often cannot simultaneously meet. These issues have long hindered the improvement of banana cultivation quality and efficiency, necessitating a systematic solution. Summary of the Invention

[0009] To address the above problems, this invention provides a method for preventing fruit rust in banana cultivation and a compound fertilizer composition.

[0010] To achieve these objectives of the present invention, the present invention provides a method for preventing fruit rust in banana cultivation, comprising:

[0011] a) From the early budding stage of banana plants to the end of harvest, apply 11 grams of the first fertilizer per plant, diluted with 5-6 jin of water, and then drench it around the base of the stem within a 40cm radius. The application frequency is once every 6 days. The first fertilizer is a water-soluble fertilizer with a nitrogen, phosphorus, and potassium ratio of 30:10:10, containing trace elements S 1.0%, Zn 0.65%, Mg 0.5%, Fe 0.2%, B 0.15%, Cu 0.01%, and Mo 0.005%.

[0012] (b) Simultaneously apply 11 g / plant of the second fertilizer, 15 g / plant of potassium chloride, and 15 g / plant of amino acid liquid organic fertilizer; the second fertilizer is a water-soluble fertilizer with a nitrogen-phosphorus-potassium ratio of 5:5:45, and contains trace elements S 1.0%, Zn 0.65%, Mg 0.5%, Fe 0.2%, B 0.15%, Cu 0.01%, and Mo 0.005%;

[0013] c) During the key stages of banana growth, including after the fruit comb has emerged, when the buds are removed, and before bagging, spray a mixture of the third and fourth fertilizers. The third fertilizer is a water-soluble fertilizer containing ≥100 g / L calcium, ≥12% humic acid, ≥8% seaweed extract, and 0.1% chelated Zn and 0.05-0.1% B, diluted 750 times. The fourth fertilizer is a water-soluble fertilizer containing ≥15% humic acid, ≥5% fulvic acid, ≥30 g / L calcium, ≥10 g / L magnesium, and ≥2% plant-derived polyphenols, diluted 1500 times.

[0014] Preferably, when spraying a mixture of the third and fourth fertilizers, a disease-resistant and fruit-protecting agent is added, but no fruit-brightening agent is added.

[0015] Preferably, a fifth fertilizer is applied from the early budding stage of bananas to the end of harvest. The spraying frequency is once every 15 days, with 10 ml of fertilizer per plant diluted in 5-6 catties of water and applied to a 40cm radius around the base of the stem each time. The fifth fertilizer is a water-soluble fertilizer containing 90 g / L calcium and 21 g / L magnesium.

[0016] Preferably, when applying fertilizer to the roots, a compound microbial agent is added, comprising one or more of Bacillus subtilis, Bacillus amyloliquefaciens, and arbuscular mycorrhizal fungi (e.g., in a ratio of 1:1:1), at a dosage of 5 grams per plant, mixed with Litian Funong fertilizer and applied by drenching. The weight ratio of the microbial agent to the fertilizer is 1:10; the total viable count of the microbial agent is ≥5×10⁻⁶. 8 CFU / g.

[0017] Preferably, methyl jasmonate (MeJA), a plant immune activator, is added to the spray mixture at a concentration of 50-100 ppm, and sprayed once each during the banana budding stage, the fruit expansion stage, and 20 days before harvest.

[0018] The methyl jasmonate enhances cross-resistance to rust, leaf spot and anthracnose, and the effect lasts into the next growth cycle.

[0019] Preferably, the method further includes: adding a modified lignin-based porous microsphere carrier to the spray mixture, wherein the microsphere carrier is prepared from agricultural waste lignin by acid hydrolysis-self-assembly method, has a pore size of 5-20 nm, a specific surface area ≥200 m² / g, and is grafted with carboxymethyl cellulose (CMC) on the surface to improve leaf adhesion.

[0020] The microsphere carrier is loaded with methyl jasmonate (MeJA) and lipopeptide antibiotics at a loading ratio of MeJA:lipopeptide = 1:2 (w / w), and the total loading accounts for 15%-20% of the microsphere mass.

[0021] The spraying method is as follows: the loaded microspheres are mixed with the mixture of claim 1 at a volume ratio of 1:4 and then sprayed. The spraying amount is 30-50 ml per plant, covering the front and back of the leaves and the surface of the fruit ears.

[0022] The porous structure of the microsphere carrier allows for the slow release of MeJA, extending its effective period and resisting UV radiation and rain erosion; the surface CMC enhances leaf adhesion, increasing leaf coverage by 40%-50% after spraying; the lipopeptide antibiotics target and inhibit the spread of rust mycelia, forming a dual protection of immunity and elimination with the systemic resistance induced by MeJA; the lignin-based carrier completely degrades in the soil in about 30 days, leaving no residual pollution.

[0023] Preferably, the modified lignin-based porous microsphere carrier is further loaded with an inclusion complex, which consists of abscisic acid (ABA) and γ-aminobutyric acid (GABA) encapsulated in a chitosan-N-isopropylacrylamide (CS-PNIPAM) thermosensitive gel at a mass ratio of ABA:GABA=1:1.

[0024] During the banana budding stage and before bagging, when the ambient temperature is between 30℃ and 40℃ and the relative humidity is ≥80% for more than 3 consecutive days, spray the aforementioned encapsulation compound and complete the spraying within 24 hours.

[0025] When the inclusion complex is at an ambient temperature ≥30℃ or relative humidity ≥80%, the gel shrinks and releases ABA and GABA, reducing the incidence of fruit rust under high temperature and high humidity conditions to below 3%.

[0026] The total loading of the microsphere carrier is 25%-30% (MeJA + lipopeptide + inclusion complex), and the humic acid released after the lignin-based carrier degrades in the soil increases the soil organic matter content by 15%-20%.

[0027] The present invention provides a compound fertilizer composition for banana cultivation, comprising the first fertilizer, the second fertilizer, the third fertilizer, the fourth fertilizer, potassium chloride, and amino acid liquid organic fertilizer, and applied according to the corresponding method.

[0028] Preferably, it also includes the aforementioned microbial inoculant and its application according to the method thereof.

[0029] Preferably, the mixture also includes the methyl jasmonate, the carrier, and the inclusion complex, and is applied according to the corresponding method.

[0030] The present invention has at least the following beneficial effects:

[0031] 1. Traditional fixed-ratio fertilization results in potassium excess during the budding stage, inhibiting nitrogen absorption; excessive nitrogen during the fruit expansion stage delays ripening; and a lack of micronutrients leads to thin fruit peels. This invention adopts a phased dynamic fertilization strategy. In the early budding stage, a high-nitrogen formula (30-10-10+TE) is applied to promote stem and leaf growth, while a high-potassium formula (5-5-45+TE) is simultaneously applied to pre-embed potassium. During the fruit expansion stage, a third and fourth fertilizer combination is used to supplement calcium and magnesium and increase humic acid content, thereby increasing the thickness of the fruit peel cell walls and reducing the incidence of fruit russeting.

[0032] 2. Conventional fungicides have a short effective period. This invention develops a modified lignin-based porous microsphere carrier (pore size 5-20nm, specific surface area ≥200 m² / g), with CMC grafted onto the surface to enhance adhesion, and loaded with methyl jasmonate and lipopeptide antibiotics (1:2) to achieve sustained release, thus extending the effective period and maintaining a high rust inhibition rate even under high temperature and high humidity environments.

[0033] 3. This invention adds a compound microbial agent (Bacillus subtilis + Bacillus amyloliquefaciens + arbuscular mycorrhizal fungi, viable count ≥ 5 × 10⁻⁶). 8 (CFU / g), mixed with fertilizer at a ratio of 1:10. Increased soil organic matter content by 85% (1.8%→3.3%), increased nitrogen fertilizer utilization rate from 58% to 82%, and narrowed yield fluctuation in continuous cropping areas from ±15% to ±5%.

[0034] 4. High temperature and humidity environments (≥30℃ / 80%RH) accelerate disease spread, and traditional solutions lack dynamic response capabilities. This invention develops a temperature-sensitive gel inclusion complex that releases ABA and GABA (1:1) at 30-40℃ / RH≥80%, synergistically releasing humic acid from the lignin carrier. Under extreme high temperature and humidity conditions, the incidence of fruit russeting is stably controlled below 0.5%, the fruit drop rate caused by high temperature stress is reduced from 12% to 2.3%, and the harvest period is extended by 7-10 days.

[0035] 5. This invention integrates six functional components—macronutrient fertilizer, amino acid organic fertilizer, microbial agents, plant hormones, antibiotics, and environmental response inclusion complexes—through a four-dimensional synergistic approach, including root microbial fertilizer conditioning, stem base nutrient regulation, foliar slow-release protection, and environmental response triggering, thereby increasing the yield per plant in the embodiments.

[0036] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0037] Figure 1 The image shows the typical morphology of banana rust, which consists of irregular brown to dark brown rust spots. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to examples, so that those skilled in the art can implement it based on the description.

[0039] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0040] The materials used in this invention are as follows:

[0041] The first fertilizer used in this invention is Litian Funong Fertilizer's 30-10-10+TE water-soluble fertilizer, which contains: nitrogen (N) 30%, phosphorus (P2O5) 10%, potassium (K2O) 10%, and trace elements (TE): S 1.0%, Zn 0.65%, Mg 0.5%, Fe 0.2%, B 0.15%, Cu 0.01%, Mo 0.005%. It is a high-nitrogen formula that promotes stem and leaf growth, enhances photosynthesis, and is suitable for the early budding stage to the vegetative growth stage. Among the trace elements, iron (Fe) prevents yellowing, zinc (Zn) regulates enzyme activity, and boron (B) promotes flower bud differentiation, working synergistically. The pH value is 6.0-6.5.

[0042] The second fertilizer used in this invention is Litian Funong Fertilizer's 5-5-45+TE water-soluble fertilizer, which contains: nitrogen (N) 5%, phosphorus (P2O5) 5%, potassium (K2O) 45%, and trace elements (TE): S 1.0%, Zn 0.65%, Mg 0.5%, Fe 0.2%, B 0.15%, Cu 0.01%, Mo 0.005%. It is an ultra-high potassium formula, which enhances fruit sugar accumulation and cell wall thickness, thereby improving disease resistance and storage tolerance. Among the trace elements, sulfur (S) promotes protein synthesis, and magnesium (Mg) enhances chlorophyll stability. pH 5.5-6.0.

[0043] This invention uses Yuansheng Peptide Amino Acid Liquid Organic Fertilizer, model YSP-15, which contains hydrolyzed plant protein (soybean meal), with an amino acid content ≥15%, an organic matter content ≥20%, and trace elements including Zn 0.1%, Fe 0.2%, and B 0.02%, which can promote root development and enhance soil microbial activity.

[0044] The third fertilizer used in this invention is Litian Funong Fruit Water-Soluble Fertilizer, model LTFG-750, with a Ca ≥ 100g / L, humic acid (≥ 12%), seaweed extract (≥ 8%), and chelated trace elements (Zn 0.1%, B 0.05~0.1%), at a concentration of 750 times. It supplements both calcium and boron, promoting calcium movement within the plant, increasing the safe absorption threshold of boron, improving the absorption and utilization rate of calcium and boron, and preventing toxicity. It also promotes fruit enlargement and sugar accumulation, enhances peel gloss, induces the expression of stress-resistant genes, and reduces physiological fruit cracking. The pH is 5.0-5.8, weakly acidic, suitable for absorption by banana fruit surfaces.

[0045] The fourth fertilizer used in this invention is Litian Funong Runzhise water-soluble fertilizer, model FNRS-1500, containing humic acid (≥15%), fulvic acid (≥5%), seaweed extract (3%), calcium (Ca) ≥30 g / L, magnesium (Mg) ≥10 g / L (total mesonutrients ≥50 g / L), zinc (Zn) 0.1%, boron (B) 0.05%, and plant-derived polyphenols ≥2% (natural antioxidants), at a concentration of 1500 times. It has a pH of 4.5-5.5, is weakly acidic, and is suitable for absorption by banana leaves. Humic acid and fulvic acid synergistically inhibit the germination of rust fungal spores, reducing the incidence of fruit rust. Polyphenols enhance the antioxidant capacity of the fruit peel, delaying post-harvest browning, while calcium increases cell wall thickness and improves peel hardness.

[0046] The fifth fertilizer used in this invention is Litian Funong Shuogen water-soluble fertilizer, model LTFG-SG10, with Ca 90 g / L, Mg 21 g / L (total Ca+Mg≥100 g / L), pH=8.5 after 1:250 dilution, and water-insoluble matter ≤50 g / L.

[0047] Potassium chloride, the present invention uses fertilizer-grade potassium chloride from Sinochem, with potassium oxide ≥60.0%.

[0048] Example 1

[0049] The present invention provides a method for preventing fruit rust in banana cultivation, comprising:

[0050] Root fertilization: Apply 11 grams of Litian Funong fertilizer (first fertilizer) with a nitrogen-phosphorus-potassium ratio of 30-10-10+TE to each plant, mix with 5-6 jin of water, and apply it to a 40cm area around the base of the stem, once every 6 days (the test site of this invention is in Guangxi, and it was applied from August to December).

[0051] Apply 11g / plant of 5-5-45+TE Litian Funong Fertilizer (second fertilizer) + 15g / plant of potassium chloride + 15g / plant of Yuansheng Peptide Amino Acid Liquid Organic Fertilizer to the roots simultaneously, mix it into the diluted solution of the first and second fertilizers, and spray it together.

[0052] Fruit spraying plan: Spray a mixture of 750 times diluted Litian Funong Fruit (third fertilizer) (1 ml: 1.5 catties water) and 1500 times diluted Funong Runzhise (fourth fertilizer) (1 ml: 3 catties water), adding 20 ml and 10 ml of each fertilizer to every 30 catties of water. Spray at key times, including: the first spray after the fruit combs have emerged, the second spray when the buds are broken, and the third spray before bagging. Add fruit protectant (such as Jianda or Chunleimycin, according to the standard method and dosage in their instructions) at the same time during spraying. Do not add any other fruit brightening liquid.

[0053] Example 2

[0054] The present invention provides a method for preventing fruit rust in banana cultivation, comprising:

[0055] Compared with Example 1, the difference is that during the period from the early budding stage of bananas to the end of harvest, Litian Funong Shuogen water-soluble fertilizer (the fifth fertilizer) is added during spraying. It is applied once every 15 days, with 10 ml per plant diluted in 5-6 catties of water, and applied within a 40cm radius around the base of the stem.

[0056] Example 3

[0057] The present invention provides a method for preventing fruit rust in banana cultivation, comprising: adding 5 grams of compound microbial agent (live bacteria count ≥ 5 × 10⁻⁶) to each plant, based on Example 1. 8 (CFU / g), mixed with 30-10-10+TE fertilizer for drenching. The compound microbial agent includes: Bacillus subtilis (viable count ≥ 2 × 10⁻⁶). 8 CFU / g), Bacillus amyloliquefaciens (live count ≥1×10⁻⁶) 8 The ratio of CFU / g to arbuscular mycorrhizal fungi (spore count ≥ 50 / g) should be 1:1:1. The total viable count of the fungal agent, as determined by plate counting, should be ≥ 5 × 10⁻⁶. 8 The inoculant has a pH range of 5.5-7.5. First, use pH test strips or a pH meter to test the pH value of the top 10cm of soil. If the soil pH is below 5.5, add lime to adjust it to 6.0-6.5; if it is above 7.5, add sulfur powder to lower the pH.

[0058] Before mixing the microbial agent with the fertilizer, dissolve the microbial agent powder in 200 ml of water (25-30℃) and stir until completely dispersed. The weight ratio of the microbial agent to the Litian Funong fertilizer is 1:10. Use a mixing bucket to mix at 200 rpm for 10 minutes to ensure even mixing. Apply the mixed fertilizer around a 40 cm radius around the base of the stem.

[0059] In this embodiment, Bacillus subtilis secretes amylase and protease to promote the decomposition of organic matter; Bacillus amyloliquefaciens produces indoleacetic acid (IAA), which stimulates root growth; and arbuscular mycorrhizal fungi (AMF) expand the root absorption range through hyphal networks, improving the utilization rate of elements such as phosphorus and zinc. The combination of these three components enhances soil organic matter and nitrogen fertilizer utilization.

[0060] Example 4

[0061] This invention discloses a method for preventing fruit rust in banana cultivation, comprising: based on Example 3, further adding methyl jasmonic acid at a concentration of 50-100 ppm to a mixture of the third and fourth fertilizers, and spraying once each during the banana budding stage, the fruit expansion stage, and 20 days before harvest. In this example, 80 ppm is used. 0.8 grams of methyl jasmonic acid with a purity ≥98% is dissolved in 10 liters of water at a temperature of 25-30°C, and stirred for 5 minutes with a magnetic stirrer until completely homogeneous.

[0062] Spraying time must be strictly controlled during the banana budding stage (when the flower buds first appear), the fruit expansion stage (when the fruit diameter reaches 5-6 cm), and 20 days before harvest. When spraying, try to cover the leaves and fruit bunches as much as possible. The amount of spraying per plant is 30-50 ml.

[0063] Add methyl jasmonate solution to the mixture at a volume ratio of 1:100, mix and stir well before application.

[0064] Example 5

[0065] The present invention discloses a method for preventing fruit rust in banana cultivation, comprising: based on Example 4, adding a modified lignin-based porous microsphere carrier to the spray mixture. The microsphere carrier is prepared by acid hydrolysis-self-assembly of lignin, with a pore size of 5-20 nm, a specific surface area ≥200 m² / g, and a surface grafted with carboxymethyl cellulose. The microsphere carrier is loaded with methyl jasmonate and lipopeptide antibiotics in a loading ratio of methyl jasmonate:lipopeptide antibiotics = 1:2 by mass, and the total loading accounts for 15%-20% of the mass of the microspheres. The spraying method is as follows: the loaded microspheres are mixed with the mixture of claim 1 at a volume ratio of 1:4 and then sprayed, with a spraying amount of 30-50 ml per plant, covering both sides of the leaves and the surface of the fruit bunch.

[0066] Specifically, lignin (Hubei Hanwei Chemical Co., Ltd. 8068-03-9, purity 98%, molecular weight 3000-5000 Da) was mixed with 5% dilute sulfuric acid at a mass ratio of 1:10. The reaction temperature was 120℃ for 2 hours, followed by washing with water until neutral to obtain acid-hydrolyzed lignin. For self-assembly, the acid-hydrolyzed lignin was dispersed in an ammonia solution (5% concentration) at pH=9, stirred at 800 rpm, and reacted at 80℃ for 4 hours. After that, 1 M HCl was added dropwise until pH=3, forming microspheres. The pore size of the microspheres was determined to be 5-20 nm by the BET method, and the specific surface area was ≥200 m² / g. For surface grafting of carboxymethyl cellulose (CMC, Hubei Shixing Chemical Co., Ltd., 9000-11-7), the microspheres were mixed with 2% CMC solution at a mass ratio of 1:2, and EDC / NHS activator was added. The reaction was carried out at 40℃ for 6 hours, followed by centrifugation and freeze-drying.

[0067] Methyl jasmonate and a lipopeptide antibiotic (Surfactin, purity ≥80%) were mixed at a mass ratio of 1:2. For loading, the drug mixture was dissolved in ethanol (concentration 20 mg / mL), and the microspheres were impregnated at a mass ratio of 1:5. The mixture was then sonicated for 30 minutes (frequency 40 kHz), and the solvent was evaporated under reduced pressure. The total loading was controlled at 15%-20%. The loaded microspheres were stored in a dry container protected from light.

[0068] Mix the loaded microspheres with the mixture of the third and fourth fertilizers at a volume ratio of 1:4, and then spray it on the surface of the leaves and fruit ears. The amount sprayed per plant is 30-50 ml.

[0069] The degradation rate of the loaded microspheres was 98.2% after 30 days, and the drug efficacy lasted for 12-18 days. In contrast, the drug efficacy lasted only 3-5 days without the loaded microspheres.

[0070] Example 6

[0071] The present invention discloses a method for preventing fruit rust in banana cultivation, comprising: based on Example 5, further loading an inclusion complex onto a modified lignin-based porous microsphere carrier, wherein the inclusion complex is composed of abscisic acid and γ-aminobutyric acid encapsulated by chitosan-N-isopropylacrylamide thermosensitive gel, with a mass ratio of abscisic acid:γ-aminobutyric acid = 1:1; the total loading of the microsphere carrier is 25%-30%; and spraying the inclusion complex within 24 hours when the ambient temperature is between 30℃-40℃ and the relative humidity is ≥80% for more than 3 consecutive days from the banana budding stage to bagging stage.

[0072] In the preparation of the inclusion complex, chitosan and N-isopropylacrylamide (NIPAM) were mixed at a mass ratio of 1:10 and reacted at 60°C with ammonium persulfate as an initiator for 6 hours. After dialysis purification, CS-PNIPAM gel was obtained, and the thermosensitive gel phase transition temperature (LCST) was measured to be 32°C ± 1°C. Abscisic acid (ABA) and γ-aminobutyric acid (GABA) were mixed at a mass ratio of 1:1 and dissolved in the gel solution (concentration 5%). Inclusion complex microspheres were formed by ionic crosslinking (0.1 M CaCl2). When loaded onto lignin microspheres, the mass ratio of inclusion complex to microspheres was 1:3, and the total loading was controlled at 25%-30%.

[0073] The microsphere carrier loaded with inclusion complex was mixed with the mixture in Example 5 (methyl jasmonate and lipopeptide were mixed at a mass ratio of 1:2) at a volume ratio of 1:4 to obtain a treatment solution, which was used for the treatment of bananas in high temperature and high humidity.

[0074] Temperature and humidity recorders were set up at the banana experimental base for real-time monitoring. Spraying was triggered when the temperature reached 32℃ and the humidity reached 85% for more than 3 consecutive days from the banana budding stage to before bagging. Spraying was carried out at a dosage of 40 ml per plant, covering the leaves and fruit bunches. If the rainfall exceeded 10 mm within 24 hours after spraying, a second spraying was required.

[0075] Comparative Example 1

[0076] Traditional fertilization method was adopted: 20 grams of a standard NPK compound fertilizer (15-15-15) was applied per plant every 10 days. No amino acid organic fertilizer or special spraying agents were added. A standard foliar fungicide, difenoconazole, was applied once a week for fungicide control.

[0077] Effect Analysis

[0078] 1. Harvest length (cm): The vertical straight-line distance from the base of the harvest cluster (where the last comb of fruit stalks attaches) to the tip of the cluster (the top of the first comb of fruit). Measurement method: Measured 3 days before harvest, when the harvest cluster is hanging naturally.

[0079] 2. Ear diameter (cm): The circumference of the largest cross section perpendicular to the main ear axis at the middle of the ear (1 / 2 of the total length) is measured using a serrated tool.

[0080] 3. Finger weight (kg): Net weight of a single banana fruit (excluding the stem). During sampling, take the 3rd, 5th, and 7th fingers from the 4th to 6th combs (middle combs) of the bunch, remove deformed fruits (curvature > 30° or scar area > 5%), cut the fingers 1 cm from the base of the stem, peel and weigh immediately (to prevent moisture evaporation), and measure each fruit 3 times to obtain a stable value.

[0081] 4. Fruit count (fruits / plant): The total number of marketable fruits (length ≥ 14 cm) on a single banana plant's mature bunch. Detection method: A full survey of the entire plant is conducted 7 days before harvest.

[0082] 5. Rust Fruit Incidence Rate: The percentage of fruits with irregular brown to dark brown rust spots on the peel surface. Detection Method: A general survey of the entire plant is conducted 7 days before harvest. Rust fruit incidence rate (%) = (Rust Spot Fruit Index / Total Fruit Index) × 100.

[0083] 6. Pericarp hardness: The puncture resistance of the pericarp on the equatorial surface of the fruit. Testing method: Using a digital fruit hardness tester, the middle fingers of the 3rd, 6th, and 9th combs of each fruit cluster are taken, peeled, and measured. The puncture speed is 2 mm / s, and the puncture depth is 5 mm. The average of three measurements is taken.

[0084] 7. Soil Organic Matter Content: The percentage of dry weight of organic matter in a unit mass of soil. Test Method: Performed according to NY / T1121.6-2006 Soil Testing Part 6. Pass the air-dried soil sample through a 0.25mm sieve, accurately weigh 0.5g, and determine the organic matter content using the potassium dichromate-sulfuric acid oxidation method at 620nm colorimetric measurement. Calculation Formula: Organic matter (g / kg) = (V0-V)×C×0.003×1.724×1000 / m; V0: blank titration volume; V: sample titration volume; C: ferrous sulfate concentration; m: soil sample mass.

[0085] 8. Duration of drug efficacy: The time during which the active ingredient in foliar pesticides maintains a concentration ≥EC50. Detection method: Functional leaves from the middle section were collected at 0, 3, 7, 12, and 18 days after spraying, flash-frozen in liquid nitrogen, freeze-dried, and extracted with methanol using ultrasonic extraction (40kHz, 30min). Quantitative detection was performed using HPLC (Agilent 1260, C18 column, mobile phase acetonitrile-0.1% formic acid water). Methyl jasmonate was detected at a wavelength of 210nm, and lipopeptides at 280nm.

[0086] 9. Carrier degradation rate: Percentage of microsphere mass loss in soil. Detection method: 1g of microspheres are placed in a 200-mesh nylon mesh bag, buried at a depth of 15cm, and samples are taken every 5 days (3 bags). The bags are dried at 105℃ to constant weight. Degradation rate (%) = (W0-Wt) / W0×100 (W0: initial mass; Wt: residual mass at time t).

[0087] 10. Leaf coverage

[0088] The effective adhesion area of ​​the pesticide solution on the leaf surface is greater than

[0089] Detection method: The staining method was used, with the addition of 0.1% sodium fluorescein tracer; imaging detection was performed by photographing the leaves under a UV lamp (365nm), and the luminescent area was analyzed using ImageJ software; calculation: coverage (%) = (fluorescent area / total leaf area) × 100.

[0090] I. Twenty plants were sampled for each example, and the data were collected for three consecutive seasons. The following is a comparison of the effect data of Examples 1 to 6 and Comparative Example 1:

[0091] Table 1

[0092]

[0093] II. High temperature and high humidity stress experiment in banana growing greenhouse

[0094] High temperature and humidity stress tests were conducted on the schemes of Example 6 and Comparative Example 1, respectively. The high temperature and humidity conditions were set as follows: 40℃ / 90%RH for 7 days. The rust rate and fruit drop rate were recorded. The results are as follows:

[0095] Table 2 High temperature and high humidity stress test (40℃ / 90%RH for 7 days)

[0096]

[0097] The fruit drop rate (%) is calculated as follows: (Number of fallen fruits / (Total number of fruits + Number of fallen fruits)) × 100. The total number of fruits refers to the number of mature fruits remaining on the plant before harvest. The number of fallen fruits refers to the number of immature fruits that naturally fall from the plant before harvest (excluding those damaged by human or mechanical means).

[0098] The results show that the present invention, employing phased dynamic fertilization combined with slow-release protection technology from the early budding stage to harvest of bananas, increased the yield per plant from 28.5±2.1 kg in the comparative example to 34.0±0.9 kg in Example 6. The morphology of the fruit bunch was simultaneously optimized, with the length increasing from 88±4 cm to 96±1 cm and the diameter increasing from 22±1 cm to 26±1 cm. The key rust prevention indicators of the present invention were significantly improved, with the number of rusted fruits decreasing from 21.0±3.0 per plant in the comparative example to 1.6±0.3 per plant in Example 6, and the peel hardness increasing from 2.6±0.2 kg / cm² to 4.6±0.2 kg / cm². Regarding nutrient utilization, the soil organic matter content increased from 1.8±0.3% in the comparative example to 3.3±0.2% in Example 6. In Example 3, after the introduction of microbial agents, the number of fruits per plant increased to 140±8. In Example 5, the use of slow-release carrier technology extended the duration of drug efficacy to more than 12 days. In Example 6, under high temperature and high humidity conditions, the incidence of rusty fruit remained ≤1.0±0.1%, and the fruit drop rate was low, effectively improving the resistance of bananas to high temperature and high humidity stress, making it suitable for improving fruit quality and ensuring commercial value in tropical and subtropical banana producing areas.

[0099] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Further modifications can be readily implemented by those skilled in the art.

Claims

1. A method for preventing fruit rust in banana cultivation, characterized in that, include: a) Apply root fertilization during the period from the early budding stage of banana plants to the end of harvest. Apply 11 grams of the first fertilizer per plant, diluted with 5-6 jin of water, and then drench it around the base of the stem within a 40cm radius. The application frequency is once every 6 days. The first fertilizer is a water-soluble fertilizer with a nitrogen, phosphorus, and potassium ratio of 30:10:10, containing trace elements S 1.0%, Zn 0.65%, Mg 0.5%, Fe 0.2%, B 0.15%, Cu 0.01%, and Mo 0.005%. (b) Simultaneously apply 11 g / plant of the second fertilizer, 15 g / plant of potassium chloride, and 15 g / plant of amino acid liquid organic fertilizer; the second fertilizer is a water-soluble fertilizer with a nitrogen-phosphorus-potassium ratio of 5:5:45, and contains trace elements S 1.0%, Zn 0.65%, Mg 0.5%, Fe 0.2%, B 0.15%, Cu 0.01%, and Mo 0.005%; c) During key stages of banana growth, including after the fruit comb has emerged, when the buds are removed, and before bagging, spray a mixture of the third and fourth fertilizers. The third fertilizer is a water-soluble fertilizer containing ≥100 g / L calcium, ≥12% humic acid, ≥8% seaweed extract, and 0.1% chelated Zn and 0.05-0.1% B, diluted 750 times. The fourth fertilizer is a water-soluble fertilizer containing ≥15% humic acid, ≥5% fulvic acid, ≥30 g / L calcium, ≥10 g / L magnesium, and ≥2% plant-derived polyphenols, diluted 1500 times. In addition, modified lignin-based porous microspheres were added to the mixture of the third and fourth fertilizers. The microspheres were prepared from lignin via acid hydrolysis-self-assembly, with a pore size of 5-20 nm and a specific surface area ≥200 m². 2 / g, surface grafted with carboxymethyl cellulose; The microsphere carriers are loaded with methyl jasmonic acid and lipopeptide antibiotics at a ratio of methyl jasmonic acid to lipopeptide antibiotics of 1:2 by mass, with the total loading amount accounting for 15%-20% of the microsphere mass. The spraying method is as follows: mix the loaded microspheres with the mixed solution at a volume ratio of 1:4 and then spray. The concentration of methyl jasmonic acid is 50-100 ppm. Spray once each during the banana budding stage, the fruit expansion stage, and 20 days before harvest. The spraying amount is 30-50 ml per plant, covering both sides of the leaves and the surface of the fruit bunch.

2. The method for preventing fruit rust in banana cultivation as described in claim 1, characterized in that, While spraying the mixture of the third and fourth fertilizers, add a disease-resistant and fruit-protecting agent, but do not add a fruit-brightening agent.

3. The method for preventing fruit rust in banana cultivation as described in claim 1, characterized in that, During the period from the early budding stage of bananas to the end of harvest, a fifth fertilizer is applied once every 15 days. Each time, 10 ml of fertilizer is diluted in 5-6 catties of water and applied to a 40cm area around the base of the stem. The fifth fertilizer is a water-soluble fertilizer containing 90 g / L of calcium and 21 g / L of magnesium.

4. The method for preventing fruit rust in banana cultivation as described in claim 1, characterized in that, When applying fertilizer to the roots, add a microbial inoculant containing one or more of Bacillus subtilis, Bacillus amyloliquefaciens, and arbuscular mycorrhizal fungi. The dosage is 5 grams per plant, mixed with the fertilizer and applied by drenching. The weight ratio of the microbial inoculant to the fertilizer is 1:10, and the total viable count of the microbial inoculant is ≥5 × 10⁻⁶. 8 CFU / g.

5. The method for preventing fruit rust in banana cultivation according to claim 1, characterized in that, The modified lignin-based porous microsphere carrier was further loaded with an inclusion complex consisting of abscisic acid and γ-aminobutyric acid encapsulated in a chitosan-N-isopropylacrylamide thermosensitive gel at a mass ratio of abscisic acid:γ-aminobutyric acid = 1:1; the total loading of the microsphere carrier was 25%-30%. When the banana budding stage is to be bagged, and the ambient temperature is between 30℃ and 40℃, and the relative humidity is ≥80% for more than 3 consecutive days, spray the encapsulation compound and complete the spraying within 24 hours.

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