Gardenia root-knot nematode prevention and control method

Abstract

The invention provides a cape jasmine root-knot nematode prevention and control method, and relates to the technical field of plant protection, the cape jasmine root-knot nematode prevention and control method comprises the four steps of preparation of a compound material, compound synergism with an organic bacterial fertilizer, field application and management after application, and according to the cape jasmine root-knot nematode prevention and control method, ricin in castor seed powder slurry can rapidly paralyze and kill root-knot nematode through direct contact; beneficial microorganisms and metabolites thereof in the fermented gardenia oil meal can induce plant root systems to generate resistance, the tolerance of plants to root-knot nematodes is improved, finally, microorganisms in the organic bacterial fertilizer can inhibit incubation and development of root-knot nematode eggs, the breeding and survival rate of nematodes is further reduced, and the yield of the nematodes is increased. Through the synergistic effect of the castor seed powder slurry, the fermented gardenia oil meal and the organic bacterial fertilizer, a contact killing-resistance induction-ovum parasitism triple prevention and control mechanism is formed, and the prevention and control effect can be well improved.

Description

Technical Field

[0001] The present invention relates to the technical field of plant protection, and in particular to a method for controlling gardenia root-knot nematodes. Background Art

[0002] Root-knot nematodes are common root parasites in forestry and agriculture, found in the roots of a wide variety of plants. They invade plant roots, forming root knots that disrupt the plant's ability to absorb nutrients, leading to poor growth, reduced yields, and, in severe cases, even plant death. Gardenia root-knot nematodes spread rapidly, causing widespread yield reductions or even death in a short period of time. This represents a major bottleneck for the healthy development of the gardenia industry, necessitating the development of a green, environmentally friendly, and effective method for controlling gardenia root-knot nematodes.

[0003] Traditional pest control methods rely primarily on chemical pesticides, which cause widespread environmental pollution during use, particularly to soil and water sources. Furthermore, the application of chemical pesticides negatively impacts non-target organisms, disrupting the stability of soil microbial communities and ecosystems. Long-term use can lead to deterioration of soil health and damage to the ecological environment.

[0004] At the same time, long-term use of chemical pesticides can easily lead to root-knot nematode resistance, gradually weakening the control effect and even making it impossible to completely control the reproduction and spread of root-knot nematodes. This makes traditional control methods face sustainability and stability issues, especially when dealing with root-knot nematode populations under different environmental conditions. Therefore, the present invention proposes a method for controlling root-knot nematodes in gardenia to address the problems existing in the existing technology. Summary of the Invention

[0005] In view of the above problems, the purpose of the present invention is to provide a method for controlling root-knot nematodes in gardenia, which has the advantages of being green, environmentally friendly and highly effective, and can solve the problems existing in the prior art.

[0006] To achieve the purpose of the present invention, the present invention is implemented through the following technical solutions: a method for controlling root-knot nematodes in Gardenia jasminoides, comprising the following steps:

[0007] Step 1: Preparation of compound materials

[0008] Prepare dried castor seeds and gardenia oil meal, ferment the gardenia oil meal in advance to obtain fermented gardenia oil meal, then grind the dried castor seeds, add clean water and mix to obtain castor seed slurry, then mix the castor seed slurry and fermented gardenia oil meal in a volume ratio of 1:3 to obtain a mixed slurry, then add 0.5% gardenia pectin by weight of the mixed slurry and stir, and after stirring, keep warm at 40°C for 6 hours to obtain a composite material;

[0009] Step 2: Compound synergy with organic fertilizer

[0010] The composite material and the pretreated organic fertilizer are stirred and mixed in a volume ratio of 1:1, and then 5% molasses water is added to adjust the water content to 55% to 60%. The mixed material is then placed in a cool place and allowed to stand for 6 to 8 hours to obtain a composite material;

[0011] Step 3: Field application

[0012] 5-10 days before transplanting gardenia, dig a circular trench with a radius of 15 cm with the gardenia planting point as the center, and then dig four radial trenches outward from the gardenia planting point. Then evenly spread the composite material into the trench, and finally cover the top with a mixture of carbonized gardenia shell powder and slaked lime, and level the ground.

[0013] Step 4: Post-application management

[0014] During the first 7 days after application, spray water every morning and evening to maintain soil moisture at 60% to 70%. Check the pH value of the topsoil every 15 days and make corresponding treatments based on the pH value. If new nodules still appear after 40 days, apply 50% of the original amount of the composite material.

[0015] The invention is further improved in that: in the step 1, the gardenia oil meal is fermented, comprising the following steps: taking dried gardenia oil meal, corn flour and banana peel powder, mixing them in a mass ratio of 10:3:1 to obtain a mixture, then adding clean water to adjust the water content to 55%-60%, then adding 3% of the total weight of the mixture by EM bacterial agent, turning and mixing the mixture evenly, and then composting and fermenting; during the fermentation process, maintaining the pile temperature at 50-55° C. for the first six days, turning the pile every three days, measuring the pH value every 24 hours starting from the tenth day, and terminating the fermentation when the pH value is 6.8-7.2 to obtain the fermented gardenia oil meal.

[0016] A further improvement is that in step 1, the castor seed slurry is prepared by grinding dried castor seeds into 100-mesh fine powder, stirring the powder into a uniform slurry at a ratio of 1 part powder to 2 parts water, placing the slurry into a light-proof container, covering the slurry with a breathable film, and placing the slurry into a constant temperature incubator at 25° C. for 24 hours to obtain the castor seed slurry.

[0017] A further improvement is that in step 2, the organic bacterial fertilizer is pretreated by mixing the beneficial bacterial fertilizer with the carbonized gardenia fruit shell powder in a volume ratio of 1:0.3.

[0018] A further improvement is that the carbonized gardenia husk powder is prepared by slowly roasting dried gardenia husks over low heat until the surface is charred black and the interior is dark brown, then cooling to room temperature, crushing the husks through a 2 mm sieve to obtain the carbonized gardenia husk powder.

[0019] A further improvement is that in step three, the input amount of the composite material is 30 to 40 kg per mu.

[0020] A further improvement is that in step three, the specific method of evenly spreading the composite material into the ditch is as follows: the composite material is spread into the annular ditch, and then covered with 5 cm of soil, followed by watering, and then 1 cm thick wet rice husks are laid at the bottom of the radial ditch, and then the composite material is spread, and then covered with 8 cm of soil and compacted, wherein the ratio of the composite material in the annular ditch to the composite material in the radial ditch is 1:1.

[0021] A further improvement is that in step three, the carbonized gardenia fruit shell powder and slaked lime are evenly mixed in a mass ratio of 3:1.

[0022] A further improvement is that in step 4, when the pH is greater than 8.0, sulfur powder is sprinkled to neutralize the solution, and when the pH is less than 7.0, decomposed pine needle fertilizer is applied.

[0023] The beneficial effects of the present invention are:

[0024] (1) The present invention utilizes the synergistic effects of natural plant ingredients, castor bean paste, fermented gardenia oil meal, and organic fertilizer, to successfully replace traditional chemical pesticides and reduce pollution to soil, water sources, and non-target organisms. Gardenia oil meal, fruit shells, and castor seeds, as agricultural waste, are effectively utilized, promoting a sustainable circular agricultural model of "turning waste into treasure." This not only reduces the cost of agricultural waste treatment but also converts it into beneficial pest control materials, providing a new solution for green agriculture.

[0025] (2) The present invention utilizes ricin in castor seed slurry to quickly paralyze and kill root-knot nematodes through direct contact, providing a rapid control effect, while the beneficial microorganisms and their metabolites in fermented gardenia oil meal can induce plant roots to produce resistance, which helps to improve the plant's tolerance to root-knot nematodes. Finally, the microorganisms in the organic fertilizer can inhibit the hatching and development of root-knot nematode eggs, further reducing the reproduction and survival rate of the nematodes. Therefore, the present invention forms a triple control mechanism of contact killing-resistance induction-egg parasitism through the synergistic effect of castor seed slurry, fermented gardenia oil meal and organic fertilizer, which can greatly improve the control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic flow chart of the steps of the present invention. DETAILED DESCRIPTION

[0027] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the examples. The examples are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0028] In the following examples, the organic fertilizer is a highly effective microbial fertilizer with an active ingredient content of up to 80%, the main component being the number of viable bacteria, an organic matter content of 45%, and a total nutrient content of ≥5.0%. All raw materials were purchased from commercial sources.

[0029] Example 1

[0030] according to Figure 1 As shown, this embodiment provides a method for controlling root-knot nematodes in Gardenia jasminoides, comprising the following steps:

[0031] Step 1: Preparation of compound materials

[0032] Prepare dry castor seeds and gardenia oil meal, because the gardenia oil meal fermentation time is longer, therefore gardenia oil meal is carried out fermentation treatment in advance, obtain fermented gardenia oil meal, take dry gardenia oil meal, corn flour and banana peel powder, according to mass ratio 10:3:1, mix, wherein corn flour is used for supplementing carbon source, banana peel powder provides oligosaccharide and promotes actinomycete proliferation, then add clear water, regulate water content to 55%, then add 3% EM bacterial agent of gross weight, turn and mix evenly rear compost fermentation, during fermentation process, maintain pile temperature 50 ℃ for the first six days, and turn the pile once every three days (upper and lower layers exchange, increase oxygen), start to measure pH value once every 24h on the tenth day (use glass electrode pH meter, get 3 points in the center of the pile and mix and measure), until pH value is 6.8 (weakly acidic to neutral, is conducive to actinomycete production chitinase) stop fermentation, obtain fermented gardenia oil meal, now fermentation product total flavonoids content ≥3%, chitinase activity ≥15U / g.

[0033] The dried castor seeds were then ground into a 100-mesh fine powder and stirred into a uniform slurry at a ratio of 1 part powder to 2 parts water (stirring speed 25 rpm / min, stirring time ≥ 30 min). The mixture was then placed in a light-proof container and covered with a breathable membrane (pore size 0.22 μm to prevent mold). The mixture was then placed in a 25° C. constant temperature incubator and allowed to stand for 24 hours (stirring at a low speed for 5 minutes every 6 hours to avoid precipitation) to obtain a castor seed slurry.

[0034] Castor seed slurry and fermented gardenia oil meal are then mixed in a volume ratio of 1:3 (100 L castor seed slurry + 300 L fermented gardenia oil meal). Gardenia pectin (i.e., 500 g / 100 L mixed slurry) is then added at 0.5% of the total weight of the castor seed slurry and fermented gardenia oil meal mixture. Stirring is initiated at 80 rpm / min for 20 minutes or longer. During mixing, the pectin molecular chains adsorb ricin and fermentation metabolites to form sustained-release colloidal particles with a diameter of 1 μm. After uniform mixing, a composite material is obtained.

[0035] Step 2: Compound synergy with organic fertilizer

[0036] The core compound obtained in the first step is mixed with the pretreated organic fertilizer in a 1:1 volume ratio to ensure better interaction between the microorganisms in the organic fertilizer and the active ingredients of the compound. After mixing, 5% molasses water (5g molasses per 100ml of water) is added. The addition of molasses water helps to enhance microbial activity and strengthen its control of nematodes. After adding molasses water, the moisture content of the mixture is adjusted to maintain between 5% and 5% to effectively support microbial activity while not being too moist to cause excessive fermentation or hinder microbial growth.

[0037] Place the mixed material in a cool place, cover with plastic sheet (with air holes), and let it stand for 6 to 8 hours to ensure that the microbial community reaches a relatively ideal activity level, providing the best effect for subsequent prevention and control.

[0038] For organic bacterial fertilizer, the pretreatment method is to mix the beneficial bacterial fertilizer with carbonized gardenia husk powder in a volume ratio of 1:0.3. The carbonized gardenia husk powder has a high surface area and microporous structure, which can absorb the functional bacteria in the organic bacterial fertilizer and prolong the survival of the bacteria. At the same time, active ingredients such as geniposide synergize with ricin in the compound material to enhance the control effect against nematodes. This dual physical and chemical action can significantly improve the effectiveness and durability of the control while reducing negative impacts on the environment.

[0039] The preparation method of carbonized gardenia fruit shell is as follows: take dry gardenia fruit shell (no mold), put it into a wok, and slowly roast it over low heat until the surface is charred black and the inside is dark brown (that is, the dry gardenia fruit shell is carbonized), then cool it to room temperature, crush it through a 2 mm sieve, and obtain carbonized gardenia fruit shell powder.

[0040] Step 3: Field application

[0041] Five days before transplanting gardenia, a circular trench (10 cm deep and 10 cm wide) with a radius of 15 cm was dug with the gardenia planting site as the center. Then, four radial trenches (30 cm long, 20 cm deep, and 8 cm wide) were dug outward from the gardenia planting site. The composite material was then evenly spread into the trench. Specifically, the composite material was spread into the circular trench, and then covered with 5 cm of fine soil. After that, water was applied. 1-2 L of clean water was slowly poured along the edge of the trench (to moisten the soil but not to accumulate water) to promote contact between the material and the surface roots. Then, a 1 cm thick layer of wet rice husk (humidity 60% ± 5%) was spread at the bottom of the radial trench. The composite material was then sprinkled in and covered with 8 cm of fine soil and compacted. The ratio of the composite material in the circular trench to the composite material in the radial trench was 1:1, and the corresponding composite material input was 30 kg per mu.

[0042] Finally, cover the top with a mixture of carbonized gardenia shell powder and slaked lime (mass ratio 3:1), using 2 kg per mu, and then rake it lightly into the soil (depth ≤ 2 cm) to avoid direct contact with the roots, and finally level the ground.

[0043] Step 4: Post-application management

[0044] For the first 7 days after application, spray water every morning and evening to maintain soil moisture at 60%. You can use a sprayer to evenly spray water to avoid excessive moisture or dryness in the soil, which will affect the effect of the composite material. Test the pH value of the topsoil (5 cm) every 15 days and perform corresponding treatment according to the pH value. Specifically:

[0045] When the pH is greater than 8.0, it indicates that the soil is too alkaline. In this case, sulfur powder should be applied for acidification. Apply 1 kg of sulfur powder per mu and mix it into the soil. The tillage depth is about 10 cm. Sulfur powder can lower the soil pH value, improve the alkaline environment of the soil, and promote the healthy growth of plant roots.

[0046] When the pH is less than 7.0, the soil is acidic, which may affect microbial growth or lead to poor nutrient absorption. In this case, decomposed pine needle fertilizer should be applied to neutralize the acidity. The role of decomposed pine needle fertilizer is to stabilize the pH in the appropriate range of weak acidity to neutrality by replenishing organic matter, improving soil structure and microbial activity. Therefore, 5 kg of decomposed pine needle fertilizer should be applied per mu and mixed into the soil at a plowing depth of 10 cm. Pine needle fertilizer can effectively alleviate soil acidity, improve soil structure, and promote soil microbial activity.

[0047] If new nodules are still found 40 days after application, it means that the control effect of root-knot nematodes is not ideal. Then apply 50% of the original amount of the composite material. When applying, spray or directly spread it according to the soil moisture conditions to ensure that the composite material can evenly penetrate into the soil and exert a lasting effect.

[0048] Post-application management steps ensure the longevity and stability of control effects through appropriate moisture control, pH monitoring and adjustment, and timely application of composite materials. Regular monitoring and timely adjustment of the soil environment help maximize the effectiveness of the composite materials and minimize adverse effects on the soil environment. Scientific management methods can further enhance the effectiveness of root-knot nematode control and promote healthy plant growth.

[0049] Example 2

[0050] according to Figure 1 As shown, this embodiment provides a method for controlling root-knot nematodes in Gardenia jasminoides, comprising the following steps:

[0051] Step 1: Preparation of compound materials

[0052] Prepare dried castor seeds and gardenia oil meal. Because the gardenia oil meal fermentation time is long, the gardenia oil meal is fermented in advance to obtain fermented gardenia oil meal. Take dried gardenia oil meal, corn flour and banana peel powder, mix them according to a mass ratio of 10:3:1, wherein the corn flour is used to supplement the carbon source, and the banana peel powder provides oligosaccharides to promote actinomycete proliferation. Then add clear water to adjust the moisture content to 60%, then add 3% of the total weight of EM bacterial agent, stir evenly and compost and ferment. During the fermentation process, maintain a pile temperature of 50°C for the first six days, and turn the pile once every three days (upper and lower layers are exchanged to increase oxygen). Start to measure the pH value every 24 hours from the tenth day (using a glass electrode pH meter, taking 3 points in the center of the pile and mixing and measuring). Stop fermentation until the pH value is 6.8-7.2 (weakly acidic to neutral, which is conducive to chitinase production by actinomycetes) to obtain fermented gardenia oil meal. Now, the fermentation product has a total flavonoid content of ≥3% and a chitinase activity of ≥15U / g.

[0053] The dried castor seeds were then ground into a 100-mesh fine powder and stirred into a uniform slurry at a ratio of 1 part powder to 2 parts water (stirring speed 25 rpm / min, stirring time ≥ 30 min). The mixture was then placed in a light-proof container and covered with a breathable membrane (pore size 0.22 μm to prevent mold). The mixture was then placed in a 25° C. constant temperature incubator and allowed to stand for 24 hours (stirring at a low speed for 5 minutes every 6 hours to avoid precipitation) to obtain a castor seed slurry.

[0054] Castor seed slurry and fermented gardenia oil meal are then mixed in a volume ratio of 1:3 (100 L castor seed slurry + 300 L fermented gardenia oil meal). Gardenia pectin (i.e., 500 g / 100 L mixed slurry) is then added at 0.5% of the total weight of the castor seed slurry and fermented gardenia oil meal mixture. Stirring is initiated at 80 rpm / min for 20 minutes or longer. During mixing, the pectin molecular chains adsorb ricin and fermentation metabolites to form sustained-release colloidal particles with a diameter of 2 μm. After uniform mixing, a composite material is obtained.

[0055] Step 2: Compound synergy with organic fertilizer

[0056] The core compound obtained in the first step is mixed with the pretreated organic fertilizer in a 1:1 volume ratio to ensure better interaction between the microorganisms in the organic fertilizer and the active ingredients of the compound. After mixing, 5% molasses water (5g molasses per 100ml of water) is added. The addition of molasses water helps to enhance microbial activity and strengthen its control of nematodes. After adding molasses water, the moisture content of the mixture is adjusted to maintain it between 60% and 60%, which can effectively support microbial activity while not being too moist to cause excessive fermentation or hinder microbial growth.

[0057] Place the mixed material in a cool place, cover with plastic sheet (with ventilation holes), and let it stand for 8 hours to ensure that the microbial community reaches a relatively ideal activity level, providing the best effect for subsequent prevention and control.

[0058] For organic bacterial fertilizer, the pretreatment method is to mix the beneficial bacterial fertilizer with carbonized gardenia husk powder in a volume ratio of 1:0.3. The carbonized gardenia husk powder has a high surface area and microporous structure, which can absorb the functional bacteria in the organic bacterial fertilizer and prolong the survival of the bacteria. At the same time, active ingredients such as geniposide synergize with ricin in the compound material to enhance the control effect against nematodes. This dual physical and chemical action can significantly improve the effectiveness and durability of the control while reducing negative impacts on the environment.

[0059] The preparation method of carbonized gardenia fruit shell is as follows: take dry gardenia fruit shell (no mold), put it into a wok, and slowly roast it over low heat until the surface is charred black and the inside is dark brown (that is, the dry gardenia fruit shell is carbonized), then cool it to room temperature, crush it through a 2 mm sieve, and obtain carbonized gardenia fruit shell powder.

[0060] Step 3: Field application

[0061] Ten days before transplanting gardenia, a circular trench (10 cm deep and 10 cm wide) with a radius of 15 cm was dug with the gardenia planting site as the center. Then, four radial trenches (30 cm long, 20 cm deep, and 8 cm wide) were dug outward from the gardenia planting site. The composite material was then evenly spread into the trench. Specifically, the composite material was spread into the circular trench, and then covered with 5 cm of fine soil. After that, water was applied. 1-2 L of clean water was slowly poured along the edge of the trench (to moisten the soil but not to accumulate water) to promote contact between the material and the surface roots. Then, a 1 cm thick layer of wet rice husk (humidity 60% ± 5%) was spread at the bottom of the radial trench. The composite material was then sprinkled in and covered with 8 cm of fine soil and compacted. The ratio of the composite material in the circular trench to the composite material in the radial trench was 1:1, and the corresponding composite material input was 40 kg per mu.

[0062] Finally, cover the top with a mixture of carbonized gardenia shell powder and slaked lime (mass ratio 3:1), using 2 kg per mu, and then rake it lightly into the soil (depth ≤ 2 cm) to avoid direct contact with the roots, and finally level the ground.

[0063] Step 4: Post-application management

[0064] For the first 7 days after application, spray water every morning and evening to maintain soil moisture at 70%. You can use a sprayer to evenly spray water to avoid excessive moisture or dryness in the soil, which will affect the effect of the composite material. Test the pH value of the topsoil (5 cm) every 15 days and perform corresponding treatment according to the pH value. Specifically:

[0065] When the pH is greater than 8.0, it indicates that the soil is too alkaline. In this case, sulfur powder should be applied for acidification. Apply 1 kg of sulfur powder per mu and mix it into the soil. The tillage depth is about 10 cm. Sulfur powder can lower the soil pH value, improve the alkaline environment of the soil, and promote the healthy growth of plant roots.

[0066] When the pH is less than 7.0, the soil is acidic, which may affect microbial growth or lead to poor nutrient absorption. In this case, decomposed pine needle fertilizer should be applied to neutralize the acidity. The role of decomposed pine needle fertilizer is to stabilize the pH in the appropriate range of weak acidity to neutrality by replenishing organic matter, improving soil structure and microbial activity. Therefore, 5 kg of decomposed pine needle fertilizer should be applied per mu and mixed into the soil at a plowing depth of 10 cm. Pine needle fertilizer can effectively alleviate soil acidity, improve soil structure, and promote soil microbial activity.

[0067] If new nodules are still found 40 days after application, it means that the control effect of root-knot nematodes is not ideal. Then apply 50% of the original amount of the composite material. When applying, spray or directly spread it according to the soil moisture conditions to ensure that the composite material can evenly penetrate into the soil and exert a lasting effect.

[0068] The conventional chemical control method was used as a control group for comparison with Example 1 and Example 2, wherein the conventional chemical control method is as follows:

[0069] (1) 7 days before transplanting: apply 10% thiazolyl granules (30 kg / mu) in the furrow;

[0070] (2) 30 days after transplanting: irrigate with 1.8% avermectin emulsifiable concentrate (1000 times dilution, 2 L / plant);

[0071] (3) Repeat the irrigation once every 60 days, for a total of 3 times per season.

[0072] The comparison results are shown in Table 1 below:

[0073] Table 1

[0074]

[0075]

[0076] The nematode reduction rate = (the number of nematodes before application - the number of nematodes 60 days after application) / the number of nematodes before application × 100%.

[0077] As shown in Table 1 above, the nematode reduction rates in Examples 1 and 2 were significantly higher than those in traditional chemical control methods, indicating that the synergistic effect of natural plant ingredients and organic fertilizer can significantly improve the control of root-knot nematodes, especially when using green control methods, which can achieve better nematode inhibition. In summary, the control effect of Example 1 is superior to traditional chemical control methods in all indicators, demonstrating the significant advantages of the present method in controlling gardenia root-knot nematodes, with a longer duration of effect, higher control effect, and lower environmental burden.

[0078] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the framework and scope of application of the present invention. Such changes and improvements are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for controlling root-knot nematodes in Gardenia jasminoides, characterized by: The following steps are involved: Step 1: Preparation of compound materials Prepare dried castor seeds and gardenia oil meal, ferment the gardenia oil meal in advance to obtain fermented gardenia oil meal, then grind the dried castor seeds, add clean water and mix to obtain castor seed slurry, then mix the castor seed slurry and fermented gardenia oil meal in a volume ratio of 1:3 to obtain a mixed slurry, then add 0.5% gardenia pectin by weight of the mixed slurry and stir, and after stirring, keep warm at 40°C for 6 hours to obtain a composite material; Step 2: Compound synergy with organic fertilizer The composite material and the pretreated organic fertilizer are stirred and mixed in a volume ratio of 1:1, and then 5% molasses water is added to adjust the water content to 55% to 60%. The mixed material is then placed in a cool place and allowed to stand for 6 to 8 hours to obtain a composite material; Step 3: Field application 5-10 days before transplanting gardenia, dig a circular trench with a radius of 15 cm with the gardenia planting point as the center, and then dig four radial trenches outward from the gardenia planting point. Then evenly spread the composite material into the trench, and finally cover the top with a mixture of carbonized gardenia shell powder and slaked lime, and level the ground. Step 4: Post-application management During the first 7 days after application, spray water every morning and evening to maintain soil moisture at 60% to 70%. Check the pH value of the topsoil every 15 days and make corresponding treatments based on the pH value. If new nodules still appear after 40 days, apply 50% of the original amount of the composite material.

2. The method for controlling root-knot nematodes in Gardenia jasminoides according to claim 1, wherein: In the step 1, the gardenia oil meal is fermented, comprising the following steps: taking dried gardenia oil meal, corn flour and banana peel powder, mixing them in a mass ratio of 10:3:1 to obtain a mixture, then adding clean water to adjust the water content to 55% to 60%, then adding 3% of the total weight of the mixture by EM bacterial agent, turning and mixing the mixture evenly, and then composting and fermenting. During the fermentation process, the compost temperature is maintained at 50 to 55° C. for the first six days, and the compost is turned every three days. Starting from the tenth day, the pH value is measured every 24 hours, and the fermentation is terminated when the pH value is 6.8 to 7.2 to obtain the fermented gardenia oil meal.

3. The method for controlling root-knot nematodes in Gardenia jasminoides according to claim 1, wherein: In step 1, the castor seed slurry is prepared by grinding dried castor seeds into 100-mesh fine powder, stirring the powder into a uniform slurry at a ratio of 1 part powder to 2 parts water, placing the powder into a light-proof container, covering the container with a breathable film, and placing the container in a constant temperature incubator at 25° C. for 24 hours to obtain the castor seed slurry.

4. The method for controlling root-knot nematodes in Gardenia jasminoides according to claim 1, wherein: In the step 2, the organic bacterial fertilizer is pretreated by mixing the beneficial bacterial fertilizer with the carbonized gardenia fruit shell powder in a volume ratio of 1:0.

3.

5. The method for controlling root-knot nematodes in Gardenia jasminoides according to claim 4, wherein: The carbonized gardenia fruit shell powder is prepared by slowly roasting dried gardenia fruit shells over a low fire until the surface is burnt black and the interior is dark brown, then cooling to room temperature, crushing the shells and passing through a 2 mm sieve to obtain the carbonized gardenia fruit shell powder.

6. The method for controlling root-knot nematodes in Gardenia jasminoides according to claim 1, wherein: In the step 3, the input amount of the composite material is 30-40 kg per mu.

7. The method for controlling root-knot nematodes in Gardenia jasminoides according to claim 1, wherein: In step three, the specific method of evenly spreading the composite material into the ditch is as follows: the composite material is spread into the annular ditch, and then covered with 5 cm of soil, followed by watering, and then 1 cm thick wet rice husks are spread on the bottom of the radial ditch, and then the composite material is spread, and then covered with 8 cm of soil and compacted, wherein the ratio of the composite material in the annular ditch to the composite material in the radial ditch is 1:

1.

8. The method for controlling root-knot nematodes in Gardenia jasminoides according to claim 1, wherein: In the step 3, the carbonized gardenia fruit shell powder and slaked lime are evenly mixed in a mass ratio of 3:

1.

9. The method for controlling root-knot nematodes in Gardenia jasminoides according to claim 1, wherein: In the step 4, when the pH value is greater than 8.0, sulfur powder is sprinkled to neutralize the pH value, and when the pH value is less than 7.0, decomposed pine needle fertilizer is applied.

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