Banana planting fruit rust prevention method and compound fertilizer composition

Abstract

The invention discloses a banana planting fruit rust prevention method, and belongs to the technical field of banana cultivation. Aiming at the problems of nutrient imbalance caused by fixed fertilization, short lasting period of leaf surface protection and high occurrence of fruit rust caused by weak peel cell walls in the prior art, the invention provides a method for applying a compound fertilizer with a specific ratio in stages from the initial stage of budding to the harvesting stage: alternately applying a first fertilizer with a nitrogen-phosphorus-potassium ratio of 30: 10: 10 and a second fertilizer with a nitrogen-phosphorus-potassium ratio of 5: 5: 45 at the root, potassium chloride and amino acid liquid organic fertilizer are synchronously matched to supplement medium trace elements; a mixed solution of a third fertilizer and a fourth fertilizer containing high calcium, humic acid and a seaweed extract is sprayed in the key growth stage, and the peel resistance is enhanced through the synergistic effect of 750-fold dilution and 1500-fold dilution. According to the method, through dynamic nutrition regulation and control and leaf surface synergistic protection, the peel hardness is remarkably improved, the fruit rust occurrence rate is effectively reduced, and the method is suitable for fruit quality improvement and commodity value guarantee in tropical and subtropical banana main producing areas.

Description

Technical Field

[0001] The present invention belongs to the technical field of banana cultivation, and specifically relates to a method for preventing fruit rust in banana cultivation and a compound fertilizer composition. Background Art

[0002] During the banana cultivation process, fruit rust disease is one of the main problems affecting fruit quality, especially with a relatively high incidence in high-temperature and high-humidity regions. The existing technologies mainly rely on chemical fungicides and fixed-ratio fertilization, but there are still the following problems and deficiencies: Traditional fertilization mostly uses compound fertilizers with a fixed ratio, without adjusting the nitrogen, phosphorus, and potassium ratios according to different growth stages of bananas (flower bud emergence stage, fruit swelling stage, maturity stage). The flower bud emergence stage requires a relatively high nitrogen content to promote the growth of stems and leaves, while the fruit swelling stage requires a high potassium content to improve fruit quality. The fixed ratio is likely to lead to nutritional imbalance: an excess of potassium during the flower bud emergence stage inhibits nitrogen absorption, and an excess of nitrogen during the fruit swelling stage delays maturity. In addition, the supplementation of medium elements such as calcium and magnesium is insufficient, resulting in a weak cell wall of the fruit peel and being easily infected by pathogens to form rust spots.

[0003] Conventional foliar spraying of fungicides (such as difenoconazole) or nutrient solutions (such as calcium fertilizers) is easily washed away by rain or decomposed by ultraviolet rays, and the effective duration is usually ≤ 3 days, requiring frequent spraying (1 - 2 times per week), increasing labor costs. Some growers add auxiliaries (such as silicone) to extend the drug efficacy, but it may clog the nozzle or damage the wax layer of the fruit surface, exacerbating the occurrence of fruit rust.

[0004] Long-term single application of chemical fertilizers leads to soil acidification (pH < 5.5) or salinization (EC value > 2.0 mS / cm), inhibiting the activities of beneficial microorganisms (such as phosphate-solubilizing bacteria and nitrogen-fixing bacteria), and the soil organic matter content decreases year by year (≤ 1.5%). The insufficient microbial activity further reduces the nitrogen fertilizer utilization rate (only 50% - 60%), and the unabsorbed nitrogen is lost through leaching or volatilization, exacerbating environmental pollution.

[0005] High-temperature (≥ 30°C) and high-humidity (≥ 80%) environments will accelerate the spread of rust spores, and at the same time weaken the plant's stress resistance. The traditional solutions lack an environmental response mechanism and cannot dynamically adjust the drug release rate when meteorological conditions change suddenly, resulting in delayed protection. In addition, the photolysis of some fungicides (such as carbendazim) accelerates at high temperatures, and the concentration of the active ingredient drops rapidly, and the disease prevention effect decreases suddenly.

[0006] Most existing foliar spraying technologies directly use liquid medicaments, lacking the design of a sustained-release carrier, and the drug utilization rate is low. Although some studies have tried nano carriers (such as silica microspheres), they are costly and have poor degradability, and may cause microplastic pollution.

[0007] The reasons for the long-term existence of these problems include: the long growth cycle of bananas (6 - 8 months), which requires multiple adjustments of the fertilizer ratio. Traditional methods are difficult to precisely match the needs of each stage, and it is easy to have nutrient waste or deficiency. Preventing diseases on the leaf surface requires taking into account sterilization, nutrient supplementation, and stress resistance induction. Single components are difficult to achieve multiple effects, while the mixing of multiple components is prone to antagonism or precipitation. There is a lack of real-time monitoring and response to environmental factors such as temperature and humidity, and it is impossible to achieve "drug release on demand", and the disease prevention stability is poor under extreme climates. The development of low-cost and degradable carrier materials is difficult, and it is necessary to balance the drug loading capacity, slow-release performance, and environmental compatibility. Most existing carriers cannot meet these requirements simultaneously. The above problems have long restricted the improvement of the quality and efficiency of banana cultivation, and a systematic solution is urgently needed. Summary of the Invention

[0008] In view of the above problems, the present invention provides a method for preventing fruit rust in banana cultivation and a compound fertilizer composition.

[0009] To achieve these objectives of the present invention, a method for preventing fruit rust in banana cultivation provided by the present invention includes: a) During the period from the initial stage of banana budding to the end of harvesting, apply 11 grams of the first fertilizer per plant, mix it with 5 - 6 catties of water, and then drench it around the base of the stem within a range of 40 cm. The application frequency is once every 6 days; the first fertilizer is a water-soluble fertilizer with a nitrogen-phosphorus-potassium ratio of 30:10:10, containing 1.0% of trace element S, 0.65% of Zn, 0.5% of Mg, 0.2% of Fe, 0.15% of B, 0.01% of Cu, and 0.005% of Mo; b) Simultaneously apply 11 grams / plant of the second fertilizer, 15 grams / plant of potassium chloride, and 15 grams / 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 1.0% of trace element S, 0.65% of Zn, 0.5% of Mg, 0.2% of Fe, 0.15% of B, 0.01% of Cu, and 0.005% of Mo; c) During the critical growth stages of bananas, including after the complete fruit comb is exposed, at the time of cutting the buds, and before bagging, spray a mixed solution of the third fertilizer and the fourth fertilizer. The third fertilizer is a water-soluble fertilizer containing ≥100 g / L of calcium, ≥12% of humic acid, ≥8% of seaweed extract, 0.1% of chelated Zn, and 0.05 - 0.1% of B, diluted 750 times; the fourth fertilizer is a water-soluble fertilizer containing ≥15% of humic acid, ≥5% of fulvic acid, ≥30 g / L of calcium, ≥10 g / L of magnesium, and ≥2% of plant-derived polyphenols, diluted 1500 times.

[0010] Preferably, when spraying the mixed solution of the third fertilizer and the fourth fertilizer, add a disease-resistant and fruit-protecting agent, and do not add a brightening solution.

[0011] Preferably, during the initial stage of banana budding to the end of harvesting, a fifth fertilizer is also applied. The spraying frequency is once every 15 days. Each time, 10 ml per plant is used and diluted with 5 - 6 catties of water and applied by drenching around the base of the stem within a range of 40 cm. The fifth fertilizer is a water-soluble fertilizer containing 90 g / L of calcium and 21 g / L of magnesium.

[0012] Preferably, when applying fertilizer to the roots, a compound microbial inoculant is added, which includes any one or more of Bacillus subtilis, Bacillus amyloliquefaciens, and arbuscular mycorrhizal fungi (such as the ratio of the three is 1:1:1). The addition amount per plant is 5 g, and it is mixed with Litian Funong fertilizer and applied by drenching. The weight ratio of the microbial inoculant to the fertilizer is 1:10. The total viable count of the microbial inoculant ≥ 5×10 8 CFU / g.

[0013] Preferably, a plant immune activator methyl jasmonate (MeJA) is added to the spraying mixture, with a concentration of 50 - 100 ppm, and it is sprayed once during the banana budding stage, fruit swelling stage, and 20 days before harvesting. The methyl jasmonate enhances cross-resistance to rust, leaf spot, and anthracnose, and the effect lasts until the next growth cycle.

[0014] Preferably, it further includes: adding a modified lignin-based porous microsphere carrier to the spraying mixture. The microsphere carrier is prepared by an acidolysis-self-assembly method from agricultural waste lignin, with a pore size of 5 - 20 nm, a specific surface area ≥ 200 m² / g, and carboxymethyl cellulose (CMC) is grafted on the surface to improve the adhesion to the leaf surface. The microsphere carrier is loaded with methyl jasmonate (MeJA) and lipopeptide antibiotics, and the loading ratio is MeJA:lipopeptide = 1:2 (w / w). The total loading amount accounts for 15% - 20% of the mass of the microspheres. The spraying method is: mixing the loaded microspheres with the mixture of claim 1 in a volume ratio of 1:4 and then spraying. The spraying amount is 30 - 50 ml per plant, covering both the front and back of the leaves and the surface of the fruit cluster. The porous structure of the microsphere carrier slowly releases MeJA, prolongs the effective period, and resists ultraviolet rays and rain erosion. The surface CMC can enhance the adhesion to the leaf surface, and the leaf coverage rate increases by 40% - 50% after spraying. The lipopeptide antibiotics target and inhibit the expansion of rust mycelia, forming an immune killing double protection with the systemic resistance induced by MeJA. The lignin-based carrier is completely degraded in the soil in about 30 days without residual pollution.

[0015] Preferably, the modified lignin-based porous microsphere carrier is further loaded with an inclusion complex, which is composed of abscisic acid (ABA) and γ-aminobutyric acid (GABA) encapsulated by a chitosan-N-isopropylacrylamide (CS-PNIPAM) thermosensitive gel, and the mass ratio is ABA:GABA = 1:1. During the period from the budding stage of bananas to before bagging, when the ambient temperature ranges from 30°C to 40°C and the relative humidity is ≥80% and continues for more than 3 consecutive days, spraying the inclusion compound and completing the spraying within 24 hours; When the ambient temperature of the inclusion complex is ≥30℃ or the relative humidity is ≥80%, the gel shrinks and releases ABA and GABA, reducing the incidence of fruit rust under high temperature and high humidity conditions to less than 3%; The total loading amount of the microsphere carrier is 25%-30% (MeJA+lipopeptide+inclusion complex), and the humic acid released after the lignin-based carrier is degraded in the soil increases the soil organic matter content by 15%-20%.

[0016] The invention provides a compound fertilizer composition for banana planting, comprising the first fertilizer, the second fertilizer, the third fertilizer, the fourth fertilizer, potassium chloride and amino acid liquid organic fertilizer, and applying the composite fertilizer composition according to corresponding methods.

[0017] Preferably, it also includes the microbial agent and its application method.

[0018] Preferably, the method further comprises the methyl jasmonate, the carrier and the inclusion compound, and is applied according to the corresponding method.

[0019] The present invention has at least the following beneficial effects: 1. Traditional fixed-ratio fertilization causes excess potassium in the budding period, inhibiting nitrogen absorption, excess nitrogen in the fruit expansion period delays maturity, and a lack of trace elements leads to weak fruit skin. The present invention adopts a phased dynamic fertilization strategy. In the early stage of budding, a high nitrogen formula (30-10-10+TE) is applied to promote stem and leaf growth, and a high potassium formula (5-5-45+TE) is used to pre-embed potassium elements; in the fruit expansion period, the third and fourth fertilizer combinations are used to supplement calcium and magnesium and increase the humic acid content, thereby increasing the thickness of the fruit skin cell wall and reducing the incidence of fruit rust.

[0020] 2. Conventional fungicides have a short effective period. The present invention develops a modified lignin-based porous microsphere carrier (pore size 5-20nm, specific surface area ≥200 m² / g), grafts CMC on the surface to enhance adhesion, and loads methyl jasmonate and lipopeptide antibiotics (1:2) to achieve sustained release, thereby extending the effective period and maintaining a high rust inhibition rate under high temperature and high humidity environments.

[0021] 3. The present invention adds a composite microbial agent (Bacillus subtilis + Bacillus amyloliquefaciens + arbuscular mycorrhizal fungi, with a viable count of ≥ 5×10 8 CFU / g), and applied with fertilizer at a ratio of 1:10. The soil organic matter content increased by 85% (1.8%→3.3%), the nitrogen fertilizer utilization rate increased from 58% to 82%, and the yield fluctuation rate in the continuous cropping area narrowed from ±15% to ±5%.

[0022] 4. High temperature and high humidity environment (≥30℃ / 80%RH) accelerates the spread of diseases, and traditional solutions lack dynamic response capabilities. The present invention develops a temperature-sensitive gel inclusion complex that releases ABA and GABA (1:1) at 30 - 40℃ / RH≥80%, and synergistically releases with the lignin carrier humic acid. Under extreme high temperature and high humidity environments, the incidence of fruit rust 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.

[0023] 5. The present invention integrates six functional components, namely macronutrient fertilizers, amino acid organic fertilizers, microbial inoculants, plant hormones, antibiotics, and environment-responsive inclusion complexes, through four-dimensional coordination of root microbial fertilizer conditioning, stem base nutrient regulation, foliar slow-release protection, and environment-responsive triggering, resulting in an increase in the yield per plant of the examples.

[0024] Other advantages, objectives, and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a fruit rust diagram of a banana, showing the typical morphology of banana fruit rust, which is irregular rust spots ranging from brown to dark brown. DETAILED DESCRIPTION OF THE INVENTION

[0026] The following examples are used to further elaborate the present invention in detail, so that those skilled in the art can implement it according to the description in the specification.

[0027] It should be understood that the terms such as "having", "comprising", and "including" used herein do not exclude the presence or addition of one or more other elements or their combinations.

[0028] The materials of the present invention are as follows: First fertilizer, the present invention uses the 30-10-10+TE water-soluble fertilizer of Litian Funong Fertilizer, which contains: nitrogen (N) 30%, phosphorus (P2O5) 10%, potassium (K2O) 10%, 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, which promotes the growth of stems and leaves, enhances photosynthesis, and is suitable for the initial budding stage to the vegetative growth stage. Among the trace elements, iron (Fe) prevents chlorosis, zinc (Zn) regulates enzyme activity, and boron (B) promotes flower bud differentiation, with a synergistic effect. The pH value is 6.0 - 6.5.

[0029] Second Fertilizer: For this invention, the 5-5-45+TE water-soluble fertilizer of Litian Funong Fertilizer is adopted, 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 a super-high potassium formula that can enhance the sugar accumulation in fruits and the cell wall thickness, and strengthen the disease resistance and storage tolerance. Among the trace elements, sulfur (S) promotes protein synthesis, and magnesium (Mg) enhances the stability of chlorophyll. pH 5.5 - 6.0.

[0030] Amino Acid Liquid Organic Fertilizer: For this invention, Yuansheng Peptide Amino Acid Liquid Organic Fertilizer, model YSP-15, is adopted, which contains plant protein hydrolysis (soybean meal), with amino acid content ≥15% and organic matter content ≥20%. Among the trace elements, Zn is 0.1%, Fe is 0.2%, and B is 0.02%, which can promote root development and enhance the activity of soil microorganisms.

[0031] Third Fertilizer: For this invention, the fruit water-soluble fertilizer of Litian Funong, model LTFG-750, is adopted, with Ca ≥100 g / L, humic acid (≥12%), seaweed extract (≥8%), chelated trace elements (Zn 0.1%, B 0.05 - 0.1%), at a concentration of 750 times. It can supply calcium and boron simultaneously, promote the movement of calcium in the crop, increase the safety absorption threshold of boron element in the crop, improve the absorption and utilization rate of calcium and boron in the crop, avoid poisoning phenomena, and at the same time has the effects of promoting fruit swelling and sugar accumulation, enhancing the glossiness of the fruit peel; inducing the expression of stress-resistant genes and reducing physiological fruit cracking. pH 5.0 - 5.8, weakly acidic, suitable for the absorption of banana fruit surface.

[0032] Fourth Fertilizer: For this invention, the Runzhise water-soluble fertilizer of Litian Funong, model FNRS-1500, is adopted, with humic acid (≥15%), fulvic acid (≥5%), seaweed element (3%), calcium (Ca) ≥30 g / L, magnesium (Mg) ≥10 g / L (total medium elements ≥50 g / L), zinc (Zn) 0.1%, boron (B) 0.05%, plant-derived polyphenols (Polyphenols) ≥2% (natural antioxidant), at a concentration of 1500 times; pH 4.5 - 5.5, weakly acidic, suitable for the absorption of banana leaves. Humic acid and fulvic acid synergistically inhibit the spore germination of rust fungi and reduce the incidence of fruit rust. Polyphenolic substances enhance the antioxidant capacity of the fruit peel and delay post-harvest browning. Calcium element increases the cell wall thickness and improves the fruit peel hardness.

[0033] Fifth Fertilizer: For this invention, the Shuogen water-soluble fertilizer of Litian Funong, model LTFG-SG10, is adopted, with Ca 90 g / L, Mg 21 g / L (total Ca + Mg ≥100 g / L), pH = 8.5 after being diluted 1:250 times, and water-insoluble substances ≤50 g / L.

[0034] Potassium chloride. In the present invention, fertilizer-grade potassium chloride from Sinochem is used, with potassium oxide ≥ 60.0%.

[0035] Example 1 A method for preventing fruit rust in banana cultivation according to the present invention includes: Root fertilization: Apply 11 grams of Litian Funong fertilizer (the first fertilizer) with a nitrogen-phosphorus-potassium ratio of 30-10-10+TE per plant, dilute it with 5-6 catties of water, and drench it around the stem base within a range of 40 cm, once every 6 days (the test plot of the present invention is in Guangxi, starting from August to December).

[0036] Simultaneously apply 11 grams / plant of 5-5-45+TE Litian Funong fertilizer (the second fertilizer) + 15 grams / plant of potassium chloride + 15 grams / plant of Yuansheng Peptide Amino Acid Liquid Organic Fertilizer to the roots, mix them into the aqueous solution of the first and second fertilizers, and spray them together.

[0037] Fruit spraying plan: Spray a mixture of 750-fold solution of Litian Funong Fruit (the third fertilizer) (1 ml: 1.5 catties of water) and 1500-fold solution of Funong Runzhise (the fourth fertilizer) (1 ml: 3 catties of water). Add 20 ml and 10 ml to every 30 catties of water. Spray at key times, including: the first time after the complete fruit comb is exposed, the second time at bud break, and the third time before bagging. When spraying, simultaneously add fruit protection agents (such as Quadris, Kasugamycin, used according to the conventional methods and dosages in their instructions), and do not add other brightening liquids.

[0038] Example 2 A method for preventing fruit rust in banana cultivation according to the present invention includes: Compared with the scheme of Example 1, the difference is that during the initial stage of banana budding to the end of harvesting, when spraying, additionally add Litian Funong Shuogen Water Soluble Fertilizer (the fifth fertilizer), drench it once every 15 days, 10 ml / plant diluted with 5-6 catties of water, and drench it within a range of 40 cm around the stem base.

[0039] Example 3 A method for preventing fruit rust in banana cultivation according to the present invention includes: On the basis of Example 1, add 5 grams of compound microbial inoculant (total viable count ≥ 5×10 8 CFU / g) per plant, and mix it with 30-10-10+TE fertilizer for drenching. The compound microbial inoculant includes: Bacillus subtilis (total viable count ≥ 2×10 8 CFU / g), Bacillus amyloliquefaciens (total viable count ≥ 1×10 8 CFU / g) and arbuscular mycorrhizal fungi (spore count ≥ 50 spores / gram), and the mass ratio is selected as 1:1:1. The total viable count of the inoculant needs to be ≥ 5×10 8CFU / g. The pH adaptation range of the microbial agent is 5.5 - 7.5. First, use a pH test paper or pH meter to detect the pH value of the topsoil about 10 cm deep. If the soil pH is lower than 5.5, add lime to adjust it to 6.0 - 6.5; if it is higher than 7.5, sulfur powder can be added to lower the pH.

[0040] Before mixing the microbial agent with the fertilizer, first dissolve the microbial agent powder in 200 ml of clear water (water temperature 25 - 30°C), and stir until it is completely dispersed. The weight ratio of the microbial agent to the Litian Funong fertilizer is 1:10. When mixing, use a stirring barrel, set the rotation speed to 200 revolutions per minute, and stir for 10 minutes to ensure uniform mixing of the microbial agent and the fertilizer. The mixed fertilizer is applied by drenching within a range of 40 cm around the stem base.

[0041] In this example, Bacillus subtilis secretes amylase, protease, etc., to promote the decomposition of organic matter; Bacillus amyloliquefaciens produces indole acetic acid (IAA) to stimulate root growth; arbuscular mycorrhizal fungi (AMF) expand the root absorption range through the hyphal network and improve the utilization rate of elements such as phosphorus and zinc. After the three are compounded, the soil organic matter and nitrogen fertilizer utilization rate are improved.

[0042] Example 4 A method for preventing fruit rust in banana cultivation according to the present invention includes: on the basis of Example 3, further add methyl jasmonate to the mixed solution of the third fertilizer and the fourth fertilizer, with a concentration of 50 - 100 ppm, and spray it once each at the banana budding stage, fruit swelling stage, and 20 days before harvest. In this example, 80 ppm is used. Dissolve 0.8 g of methyl jasmonate with a purity of ≥98% in 10 liters of clear water, with the water temperature of the clear water being 25 - 30°C, and use a magnetic stirrer to stir for 5 minutes until it is completely uniform.

[0043] The spraying time needs to be strictly controlled at the banana budding stage (when the flower bud first appears), the fruit swelling stage (when the fruit diameter reaches 5 - 6 cm), and 20 days before harvest. When spraying, try to cover the surface of the leaves and the fruit cluster as much as possible, and the spraying amount per plant is 30 - 50 ml.

[0044] Add methyl jasmonate solution to the mixed solution at a volume ratio of 1:100, mix and stir evenly before use.

[0045] Example 5 A method for preventing fruit rust in banana cultivation of the present invention includes: on the basis of Example 4, adding a modified lignin-based porous microsphere carrier to the sprayed mixture. The microsphere carrier is prepared by an acidolysis-self-assembly method from lignin, with a pore size of 5-20 nm, a specific surface area ≥200 m² / g, and carboxymethyl cellulose grafted on the surface; the microsphere carrier is loaded with methyl jasmonate and lipopeptide antibiotics, and the loading ratio is methyl jasmonate: lipopeptide antibiotics = 1:2 by mass ratio, and the total loading amount accounts for 15%-20% of the mass of the microspheres; the spraying method is: mixing the loaded microspheres with the mixture of Claim 1 in a volume ratio of 1:4 and then spraying, with a spraying amount of 30-50 ml per plant, covering both the front and back sides of the leaves and the surface of the fruit spike.

[0046] Specifically, lignin (Hubei Hanwei Chemical Co., Ltd., 8068-03-9, purity 98%, molecular weight 3000-5000 Da) is mixed with 5% dilute sulfuric acid in a mass ratio of 1:10, the reaction temperature is 120°C, and the time is 2 hours. Subsequently, it is washed with water until neutral to obtain acidolysis lignin. During self-assembly, the acidolysis lignin is dispersed in an ammonia water solution (concentration 5%) with a pH of 9, the stirring speed is 800 revolutions per minute, the temperature is 80°C, and after reacting for 4 hours, 1 M HCl is added dropwise until the pH = 3 to form microspheres. The pore size of the microspheres is measured by the BET method to be 5-20 nm, and the specific surface area ≥200 m² / g. When grafting carboxymethyl cellulose (CMC, Hubei Shixing Chemical Co., Ltd., 9000-11-7) on the surface, the microspheres are mixed with a 2% CMC solution in a mass ratio of 1:2, an EDC / NHS activator is added, and the reaction is carried out at 40°C for 6 hours, followed by centrifugation and freeze-drying.

[0047] Methyl jasmonate and lipopeptide antibiotics (Surfactin, purity ≥80%) are mixed in a mass ratio of 1:2. During loading, the mixed drug is dissolved in ethanol (concentration 20 mg / mL), impregnated in a mass ratio of microspheres to the solution of 1:5, ultrasonic treatment is carried out for 30 minutes (frequency 40 kHz), and the solvent is evaporated under reduced pressure. The total loading amount is controlled at 15%-20%. The loaded microspheres need to be stored in a dry container away from light.

[0048] Mix the loaded microspheres with the mixture of the third fertilizer and the fourth fertilizer in a volume ratio of 1:4, and then spray on the surfaces of the leaves and the fruit spike, with a spraying amount of 30-50 ml per plant.

[0049] The degradation rate of the loaded microspheres tested for 30 days is 98.2%, and the drug persistence period is 12-18 days. In contrast, without using the loaded microspheres, the drug persistence period is only 3-5 days.

[0050] Example 6 A method for preventing fruit rust in banana cultivation of the present invention includes: on the basis of Example 5, the modified lignin-based porous microsphere carrier is further loaded with an inclusion complex, which is composed of abscisic acid and γ-aminobutyric acid encapsulated by chitosan-N-isopropylacrylamide thermosensitive gel, and the mass ratio of abscisic acid to γ-aminobutyric acid is 1:1; the total loading amount of the microsphere carrier is 25%-30%; during the period from the emergence of banana buds to before bagging, when the ambient temperature ranges from 30°C to 40°C, the relative humidity ≥ 80%, and it lasts continuously for more than 3 days, the inclusion complex is sprayed and the spraying is completed within 24 hours.

[0051] When preparing the inclusion complex, chitosan and N-isopropylacrylamide (NIPAM) are mixed in a mass ratio of 1:10, reacted at 60°C with ammonium persulfate as the initiator for 6 hours, and after dialysis purification, CS-PNIPAM gel is obtained. The phase transition temperature (LCST) of the thermosensitive gel is detected to be 32°C ± 1°C. Abscisic acid (ABA) and γ-aminobutyric acid (GABA) are mixed in a mass ratio of 1:1 and dissolved in the gel solution (concentration 5%), and inclusion complex microspheres are formed by the ion cross-linking method (0.1 M CaCl2). When loading onto lignin microspheres, the mass ratio of the inclusion complex to the microspheres is 1:3, and the total loading amount is controlled at 25%-30%.

[0052] The microsphere carrier loaded with the inclusion complex is mixed with the mixed solution in Example 5 (the mixed solution obtained by mixing methyl jasmonate and lipopeptide in a mass ratio of 1:2) in a volume ratio of 1:4 to obtain a treatment solution for treating the high temperature and high humidity danger of bananas.

[0053] A temperature and humidity recorder is set up in the banana experimental base for real-time monitoring. During the period from the emergence of banana buds to before bagging (about 3 months), when the temperature reaches 32°C and the humidity is 85%, and it lasts continuously for more than 3 days, spraying is triggered, and the spraying operation is carried out at a spraying amount of 40 ml per plant, covering the leaves and the surface of the ear. If the rainfall exceeds 10 mm within 24 hours after spraying, it is necessary to re-spray once.

[0054] Comparative Example 1 Adopt the traditional fertilization scheme: use compound fertilizer with a conventional nitrogen-phosphorus-potassium ratio of 15-15-15, 20 grams per plant, once every 10 days. No amino acid organic fertilizer and special spraying agent are added. Use the conventional foliar spraying fungicide difenoconazole for sterilization, spraying once a week.

[0055] Effect analysis 1. Ear length (cm): The vertical straight-line distance from the base of the ear (the place where the stalk of the last comb of fruits is attached) to the tip of the ear (the top of the first comb of fruits). Detection method: Measure when the ear is in a natural drooping state 3 days before harvesting.

[0056] 2. Ear thickness (cm): Use a toothed roll to measure the maximum cross-sectional circumference perpendicular to the main ear axis at the middle of the ear (at the 1 / 2 of the total length).

[0057] 3. Fruit finger weight (kg): the net weight of a single banana fruit (excluding the fruit stalk). When sampling, take the 3rd, 5th and 7th fruit fingers of the 4th to 6th combs (middle fruit combs) of the bunch, remove deformed fruits (bending degree > 30° or scar area > 5%), cut the fruit fingers 1 cm from the base of the fruit stalk, weigh them immediately after peeling (to prevent water evaporation), and measure each fruit 3 times to obtain the stable value.

[0058] 4. Fruit index (pieces / plant): The total number of commercially viable fruits (length ≥ 14 cm) on a single banana plant’s ripe bunches. Detection method: Complete a full plant survey 7 days before harvest.

[0059] 5. Rust fruit incidence: The percentage of fruits with brown to dark brown irregular rust spots on the surface of the fruit skin. Detection method: 7 days before harvest, the whole plant is surveyed, and the rust fruit incidence (%) = (Rust fruit index / total fruit index) × 100.

[0060] 6. Peel hardness: The puncture resistance of the fruit’s equatorial surface. Test method: Use a digital fruit hardness tester to measure the puncture resistance of the fruit skin at the middle equatorial surface of the fruit. Test the fruit hardness of the fruit skin by taking the middle fruit fingers of the 3rd, 6th, and 9th combs of each bunch of fruit, peeling the fruit, and measuring the fruit skin after peeling. The puncture speed is 2 mm / s, the puncture depth is 5 mm, and the average of the 3 measurements is taken.

[0061] 7. Soil organic matter content: the dry weight percentage of organic matter in unit mass of soil. Detection method: According to Part 6 of NY / T1121.6-2006 Soil Testing, air-dried soil sample is passed through a 0.25mm sieve, 0.5g is accurately weighed, potassium dichromate-sulfuric acid oxidation method is used, 620nm colorimetric determination, 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.

[0062] 8. Drug persistence: the time for the active ingredients of the drug on the leaves to maintain a concentration of ≥EC50. Detection method: Take the middle functional leaves 0, 3, 7, 12, and 18 days after spraying, freeze-freeze in liquid nitrogen, and then freeze-dry, extract with methanol ultrasonically (40kHz, 30min), and use HPLC (Agilent 1260, C18 column, mobile phase acetonitrile-0.1% formic acid water) for quantitative detection, methyl jasmonate detection wavelength 210nm, lipopeptide 280nm.

[0063] 9. Carrier degradation rate: The percentage of mass loss of microspheres in soil. Detection method: 1g of microspheres were placed in a 200-mesh nylon mesh bag, buried at a depth of 15cm, and 3 bags were taken every 5 days for sampling, and dried at 105℃ to constant weight; degradation rate (%) = (W0-Wt) / W0×100 (W0: initial mass; Wt: residual mass at time t).

[0064] 10. Leaf coverage rate Effective attachment area ratio of the liquid medicine on the leaf surface Detection method: Use the staining method, add 0.1% sodium fluorescein tracer; imaging detection, take pictures of the leaves under an ultraviolet lamp (365nm), and analyze the luminous area with ImageJ software; calculation: coverage rate (%) = (fluorescent area / total leaf area) × 100.

[0065] I. Sample and count 20 plants for each example, and continuously count for 3 seasons. The following is the comparison of the effect data of Examples 1 to 6 and Comparative Example 1: Table 1 II. Conduct high-temperature and high-humidity stress tests in a banana planting greenhouse Conduct high-temperature and high-humidity stress tests on the schemes of Example 6 and Comparative Example 1 respectively. The high-temperature and high-humidity conditions are set as: 40°C / 90% RH for 7 days, and count the rusty fruit rate and fruit drop rate respectively. The results are as follows: Table 2 High-temperature and high-humidity stress test (40°C / 90% RH for 7 days) Among them, the fruit drop rate (%) = (number of dropped fruits / (total number of fruits on the tree + number of dropped fruits)) × 100. The total number of fruits on the tree is the number of mature fruits finally retained on the plant before harvesting. The number of dropped fruits is the number of immature fruits naturally dropped from the plant before harvesting (excluding artificial or mechanical damage).

[0066] From the above results, it can be seen that the present invention adopts a stage-based dynamic fertilization combined with a slow-release protection technology from the initial budding stage to the harvesting stage of bananas. The single-plant yield is increased from 28.5 ± 2.1 kg in the comparative example to 34.0 ± 0.9 kg in Example 6, and the ear morphology is synchronously optimized. The length is increased from 88 ± 4 cm to 96 ± 1 cm, and the thickness is expanded from 22 ± 1 cm to 26 ± 1 cm. The key rust prevention index of the present invention is significantly improved. The number of rusty fruits is reduced 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 is increased from 2.6 ± 0.2 kg / cm² to 4.6 ± 0.2 kg / cm². In terms of nutrient utilization, the soil organic matter content is increased from 1.8 ± 0.3% in the comparative example to 3.3 ± 0.2% in Example 6. After introducing the microbial inoculant in Example 3, the number of fruits per finger per plant is increased to 140 ± 8; the slow-release carrier technology adopted in Example 5 extends the drug effective period to more than 12 days. In Example 6, the rusty fruit incidence rate remains ≤ 1.0 ± 0.1% under high-temperature and high-humidity conditions, and the fruit drop rate is low, effectively improving the resistance of bananas to high-temperature and high-humidity stress, and is suitable for improving the fruit quality and ensuring the commercial value in the main banana production areas in the tropical and subtropical regions.

[0067] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily achieved.

Claims

1. A method for preventing fruit rust in banana cultivation, characterized in that, Including: a) During the initial stage of banana budding to the end of harvesting, root fertilization is carried out. 11 grams of the first fertilizer is applied per plant, mixed with 5 - 6 catties of water and then drenched around the stem base within a range of 40 cm. The application frequency is once every 6 days. The first fertilizer is a water-soluble fertilizer with a nitrogen-phosphorus-potassium ratio of 30:10:10, containing 1.0% of trace element S, 0.65% of Zn, 0.5% of Mg, 0.2% of Fe, 0.15% of B, 0.01% of Cu, and 0.005% of Mo; b) Synchronously apply 11 grams / plant of the second fertilizer, 15 grams / plant of potassium chloride, and 15 grams / 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 1.0% of trace element S, 0.65% of Zn, 0.5% of Mg, 0.2% of Fe, 0.15% of B, 0.01% of Cu, and 0.005% of Mo; c) During the key growth stages of bananas, including after the complete fruit comb is exposed, at the time of cutting the bud, and before bagging, spray a mixture of the third fertilizer and the fourth fertilizer. The third fertilizer is a water-soluble fertilizer containing ≥100 g / L of calcium, ≥12% of humic acid, ≥8% of seaweed extract, and 0.1% of chelated Zn, 0.05 - 0.1% of B, and is diluted 750 times. The fourth fertilizer is a water-soluble fertilizer containing ≥15% of humic acid, ≥5% of fulvic acid, ≥30 g / L of calcium, ≥10 g / L of magnesium, and ≥2% of plant-derived polyphenols, and is diluted 1500 times.

2. The banana planting method for preventing fruit rust according to claim 1, wherein, When spraying the mixture of the third fertilizer and the fourth fertilizer, add a disease-resistant fruit protection agent and do not add a brightening liquid.

3. The banana planting method for preventing fruit rust according to claim 1, wherein During the initial stage of banana budding to the end of harvesting, the fifth fertilizer is also applied. The spraying frequency is once every 15 days. Each time, 10 milliliters per plant is mixed with 5 - 6 catties of water and drenched around the stem base within a range of 40 cm. The fifth fertilizer is a water-soluble fertilizer containing 90 g / L of calcium and 21 g / L of magnesium.

4. The banana cultivation method for preventing fruit rust according to claim 1, characterized in that, When applying fertilizer to the roots, a compound microbial inoculant is added, which includes any one or more of Bacillus subtilis, Bacillus amyloliquefaciens, and arbuscular mycorrhizal fungi. The addition amount per plant is 5 grams, and it is mixed with the fertilizer and drenched. The weight ratio of the microbial inoculant to the fertilizer is 1:

10. The total viable count of the microbial inoculant is ≥5×10 8 CFU / g.

5. The banana planting method for preventing fruit rust according to claim 1, characterized in that, Methyl jasmonate is also added to the spraying mixture, with a concentration of 50 - 100 ppm, and is sprayed once each at the banana budding stage, the fruit swelling stage, and 20 days before harvesting.

6. The rust removal method according to claim 5, wherein A modified lignin-based porous microsphere carrier is also added to the spraying mixture. The microsphere carrier is prepared by an acidolysis-self-assembly method from lignin, with a pore size of 5 - 20 nm, a specific surface area ≥200 m² / g, and carboxymethyl cellulose grafted on the surface. The microsphere carrier is loaded with methyl jasmonate and lipopeptide antibiotics, and the loading ratio is methyl jasmonate:lipopeptide antibiotics = 1:2 by mass, and the total loading amount accounts for 15% - 20% of the microsphere mass; The spraying method is: Mix the loaded microspheres with the mixture of claim 1 in a volume ratio of 1:4 and then spray. The spraying amount is 30 - 50 milliliters per plant, covering both the front and back of the leaves and the surface of the fruit cluster.

7. The rust removal method according to claim 6, characterized in that The modified lignin-based porous microsphere carrier is further loaded with an inclusion complex. The inclusion complex is composed of abscisic acid and γ-aminobutyric acid wrapped by chitosan-N-isopropylacrylamide thermosensitive gel, and the mass ratio is abscisic acid:γ-aminobutyric acid = 1:

1. The total loading amount of the microsphere carrier is 25% - 30%; Before the banana shows the bud until before bagging, when the ambient temperature ranges from 30°C to 40°C, the relative humidity ≥ 80%, and it lasts continuously for more than 3 days, spray the clathrate and complete the spraying within 24 hours.

8. A compound fertilizer composition for banana cultivation, characterized in that, It includes the first fertilizer, the second fertilizer, the third fertilizer, the fourth fertilizer, potassium chloride and amino acid liquid organic fertilizer described in claim 3, and is applied according to the method thereof.

9. The composite fertilizer composition for banana cultivation according to claim 8, characterized in that, It also includes the microbial inoculum described in claim 4 and is applied according to the method thereof.

10. The composite fertilizer composition for banana cultivation according to claim 8, characterized in that, It also includes methyl jasmonate described in claim 5, the carrier described in claim 6, the clathrate described in claim 7, and is applied according to the corresponding method.

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