Comprehensive prevention and control method for tobacco root knot nematode disease containing biological agent

Abstract

The invention discloses a comprehensive prevention and control method for tobacco root knot nematode disease containing a biological agent. The method comprises the steps of crop rotation of tobacco and buckwheat / quinoa, host resistance induction of the microbial agent in the seedling raising period, tobacco planting soil quality improvement in the transplanting period and the like. The agronomic characters of tobacco seedlings are effectively improved, and the physical characters of soil are improved; the chemical properties of soil pH, alkali-hydrolyzable nitrogen, available phosphorus, quick-acting potassium, exchangeable calcium, exchangeable magnesium and the like are improved; the activity of soil urease, sucrase, acid phosphatase, catalase and peroxidase is improved; the content of water-soluble phenols, compound phenols and total phenols in soil is reduced; the disease index of the tobacco root knot nematode disease can be remarkably reduced, the survival rate of tobacco is increased, the application amount of chemical agents is reduced, and the healthy and sustainable development of the tobacco industry is promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of tobacco planting and plant protection, and specifically relates to a comprehensive prevention and control method for tobacco root-knot nematode disease containing a biological bacterial agent. Background Art

[0002] Tobacco (Nicotiana tabacum L.) is one of the important economic crops in my country, and its cultivation is easily subject to strong constraints from many ecological factors such as climate and soil. In recent years, the harm of tobacco root knot nematode disease has become one of the obstacles restricting the development of the industry. Tobacco root knot nematode disease is caused by plant root knot nematodes (Meloidogyne spp.), which mainly harms the roots of tobacco and seriously affects the healthy development of tobacco. At the same time, the mechanical wounds caused by root knot nematode infection on tobacco can easily induce a variety of tobacco rhizome diseases, such as tobacco black shank disease, Fusarium root rot, root black rot, bacterial wilt, etc. The complex infection diseases formed cause the tobacco plants to grow weakly and have poor resistance, which in turn aggravates the occurrence and prevalence of various tobacco diseases.

[0003] Root-knot nematodes have a wide host range, including a variety of crops and weeds. They are spread through soil and water. Especially in tobacco fields with continuous and dense planting, the disease spreads quickly and it is difficult to completely block the transmission route. In addition, when the root-knot nematodes are mildly or moderately infected, the tobacco plants may not show obvious external symptoms, making it difficult to detect and treat the disease in time. Furthermore, there are many different species of root-knot nematodes, and they show different sensitivities to different prevention and control measures, which requires that the prevention and control strategies must be targeted, increasing the complexity of prevention and control.

[0004] At present, the prevention and control of root-knot nematode disease mainly relies on chemical agents. The problem of pesticide residues in tobacco as a smoking food has attracted attention. Chemical nematicides will increase the pesticide residues in tobacco leaves, causing the pesticide residues in tobacco leaves to exceed the standard, thus becoming a difficult problem in tobacco production and trade. In addition, the application of chemical nematicides seriously pollutes the environment, is unsafe for humans and animals during use, and poses a great threat to the environment. It is difficult to ensure the sustainable development and safety of tobacco production. Therefore, some nematicides that were originally very effective have stopped production or are banned in some areas. In addition, long-term use of the same or several chemical pesticides will cause nematodes to develop resistance, that is, the nematodes' sensitivity to drugs will decrease, thereby reducing the control effect of the drugs. Therefore, it is difficult to achieve ideal control effects with a single chemical agent.

[0005] The prevention and control of root-knot nematode disease is a complex system project that requires comprehensive consideration of multiple factors, including the biological characteristics of nematodes, environmental conditions, the selection and use of pesticides, etc. Only the scientific and rational application of chemical pesticides can achieve effective prevention and control effects. Summary of the invention

[0006] To overcome the problems existing in the prior art, the object of the present invention is to provide an integrated control method for tobacco root-knot nematode disease containing a biological bacterial agent, which can effectively improve agronomic traits such as tobacco seedling plant height, root length, maximum leaf length, maximum leaf width and stem girth; improve physical properties such as soil bulk density, total porosity, soil aggregate structure, soil saturated water holding capacity, capillary water holding capacity and field water holding capacity; improve chemical properties such as soil pH, available nitrogen, available phosphorus, available potassium, exchangeable calcium and exchangeable magnesium; improve the activities of soil urease, sucrase, acid phosphatase, catalase and peroxidase; reduce the contents of soil water-soluble phenols, compound phenols and total phenols; through this method, the disease index of tobacco root-knot nematode disease can be significantly reduced, the survival rate of tobacco can be improved, the application amount of chemical agents can be reduced, and the healthy and sustainable development of the tobacco industry can be promoted. The present invention comprehensively applies agricultural, biological, physical and other effective biological control technologies to control the harm of tobacco root-knot nematode disease below the allowable level of economic damage, maintain the biodiversity in the tobacco field ecosystem, and realize the green development of the tobacco industry.

[0007] To achieve the above object, the present invention is realized through the following technical solutions: An integrated control method for tobacco root-knot nematode disease containing a biological bacterial agent, comprising the following steps:

[0008] S1, Implement a two-year four-crop rotation planting system of tobacco and buckwheat / quinoa in the plot for planting tobacco;

[0009] S2, Induce host resistance with a microbial bacterial agent during the seedling stage, and apply a compound microbial bacterial agent when cultivating tobacco seedlings; the compound microbial bacterial agent contains the following components in mass fractions: Bacillus velezensis with a preservation number of CCTCC No. M2022923 5%, Bacillus subtilis with a preservation number of CCTCC No. M 20221207 5%, Pseudomonas qingdaonensis with a preservation number of CCTCC No. M2023153 5%, protein peptide powder 10%, mineral source fulvic acid potassium 10%, molasses 65%; the contents of Bacillus velezensis, Bacillus subtilis and Pseudomonas qingdaonensis in the compound microbial bacterial agent are not less than 3×10 9 cfu / g; wherein, the method for applying the compound microbial bacterial agent is: add 0.5 - 1.0 kg of the microbial bacterial agent to each cubic meter of conventional seedling substrate and then sow; and / or, when the 4th leaf of the tobacco seedling grows out, top-dress 0.5 - 1.0 kg of the compound microbial bacterial agent per 100 square meters; and / or, 7 days before transplanting, top-dress 0.5 - 1.0 kg of the compound microbial bacterial agent per 100 square meters;

[0010] S3. Improvement of the soil quality for tobacco planting during the transplanting period. The improvement of the soil quality for tobacco planting is as follows: after the rotation crop is harvested, the soil is deeply plowed by 30 - 40 cm, then flooded for 7 - 10 days, and then sunned for 10 - 15 days; 45 - 60 kg of soil conditioner is applied per mu before planting tobacco; the soil conditioner contains the following components by mass fraction: 25% CaO, 16% MgO, 56% lime, 1% potassium phosphite, 1% copper sulfate, 0.5% zinc sulfate, and 0.5% ferrous sulfate.

[0011] Further, the tobacco root - knot nematode disease is Meloidogyne incognita.

[0012] Through the above technical solutions, the present invention can at least achieve the following beneficial effects:

[0013] 1. The characteristics of the present invention are as follows: aiming at the pathogen species and the occurrence and epidemic characteristics of tobacco root - knot nematode disease in the tobacco - growing areas of Yunnan, comprehensive control of tobacco root - knot nematode disease is carried out through the coordinated action of multiple technical measures such as crop rotation, induction of host resistance by microbial inoculants during the seedling - raising period, and improvement of the soil quality for tobacco planting, playing complementary roles and achieving the best control effect.

[0014] 2. The present invention uses crop rotation between tobacco and non - Solanaceae crops, making full use of the regulatory effects of rotation crops such as buckwheat / sweet potato / quinoa on the physical properties, chemical properties, and fertility of the soil, overcoming soil quality degradation caused by continuous cropping obstacles or unreasonable crop rotation, and providing guarantee for tobacco plants to resist root - knot nematode disease. Reasonable arrangement of the rotation of previous and subsequent crops can utilize their beneficial effects and prevent adverse factors, thereby improving the physical and chemical properties of the soil, regulating soil fertility, and further enhancing the disease resistance of tobacco plants.

[0015] 3. The present invention adds microbial inoculants to the seedling - raising substrate, and proposes to mix carriers such as protein peptide powder, mineral - source fulvic acid potassium, and molasses with Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis. On the one hand, the protection and function - promoting effects of the carriers on the strains are utilized, and different carriers and their combinations have different effects on the strains; on the other hand, the composition has the effect of promoting the agronomic traits of tobacco seedlings, thereby promoting the disease - resistance ability of tobacco seedlings to root - knot nematode disease.

[0016] 4. There is a close relationship between the occurrence and prevalence of tobacco root-knot nematode disease and soil quality. Overcultivation, unreasonable fertilization and irrigation, and excessive use of chemical pesticides can lead to the destruction of soil structure, reduction of organic matter content, and decrease of microbial diversity, thus weakening the disease resistance of tobacco to root-knot nematode disease. Therefore, good soil quality can provide sufficient nutrients and suitable environmental conditions for tobacco growth, thereby enhancing the disease resistance of crops to root-knot nematode disease. The present invention innovatively combines measures such as deep plowing of soil, water soaking, sun drying, and application of soil conditioner, and enhances the disease control effect by optimizing soil structure, enhancing soil fertility, promoting soil biodiversity, and improving soil environment. Detailed implementation mode

[0017] Unless otherwise specified, the materials and reagents used in the present invention are commercially available.

[0018] In the ranges disclosed herein, the endpoints and any values are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0019] The inventor found in the research that crop rotation of buckwheat / quinoa and tobacco can improve the physical properties of tobacco-growing soil, improve the chemical properties of tobacco-growing soil, regulate the fertility of tobacco-growing soil, overcome continuous cropping obstacles, promote the healthy growth of tobacco plants, and is beneficial to reducing the occurrence and prevalence of tobacco root-knot nematode disease.

[0020] The inventor found in the research that a composite microbial agent is prepared by mixing carriers such as protein peptide powder, mineral source fulvic acid potassium, and molasses with Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis in a certain proportion, and is applied to tobacco seedling substrates and / or sprayed on tobacco seedlings, which can improve the agronomic traits of tobacco seedlings, enhance the disease resistance of tobacco plants, and further contribute to reducing the disease index of tobacco root-knot nematode disease.

[0021] The inventor found in the research that after the rotation crop is harvested, the tobacco-growing soil is deeply plowed, then flooded and soaked, turned over and sun-dried, and a soil conditioner is applied before planting tobacco. Finally, the structure of the tobacco-growing soil is optimized, the soil fertility is enhanced, the soil biodiversity is promoted, the soil environment is improved, and the disease index of tobacco root-knot nematode disease is significantly reduced.

[0022] Based on this, the present invention provides a comprehensive control method for tobacco root-knot nematode disease containing a biological agent, comprising the following steps:

[0023] S1. Implement a two-year four-crop rotation planting system of tobacco and buckwheat / quinoa in the tobacco-growing plots.

[0024] S2. Induce host resistance with microbial inoculants during the seedling stage. Apply a compound microbial inoculant when cultivating tobacco seedlings. The compound microbial inoculant contains the following components by mass fraction: Bacillus velezensis with a preservation number of CCTCC No. M2022923, 5%; Bacillus subtilis with a preservation number of CCTCC No. M20221207, 5%; Pseudomonas qingdaonensis with a preservation number of CCTCC No. M2023153, 5%; protein peptide powder, 10%; mineral source fulvic acid potassium, 10%; molasses, 65%. The contents of Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis in the compound microbial inoculant are all not less than 3×10 9 cfu / g. Among them, the method of applying the compound microbial inoculant is as follows: Sow after adding 0.5 - 1.0 kg of the microbial inoculant to every cubic meter (m 3 ) of conventional seedling-raising substrate; and / or, top-dress 0.5 - 1.0 kg of the compound microbial inoculant per 100 square meters (m 2 ) when the 4th leaf of the tobacco seedlings grows; and / or, top-dress 0.5 - 1.0 kg of the compound microbial inoculant per 100 square meters (m 2 ) 7 days before transplanting.

[0025] S3. Improve the quality of the tobacco-planting soil during the transplanting period. The improvement of the tobacco-planting soil means that after the rotation crop is harvested, the soil is deeply plowed by 30 - 40 cm, flooded for 7 - 10 days, and then sun-dried for 10 - 15 days. Apply 45 - 60 kg of soil conditioner per mu and then plant tobacco. The soil conditioner contains the following components by mass fraction: CaO, 25%; MgO, 16%; lime, 56%; potassium phosphite, 1%; copper sulfate, 1%; zinc sulfate, 0.5%; and ferrous sulfate, 0.5%.

[0026] Preferably, the tobacco root-knot nematode disease is Meloidogyne incognita.

[0027] In step S1, the two-year four-crop rotation planting system means that in the first year: flue-cured tobacco - buckwheat / quinoa → in the second year: flue-cured tobacco - buckwheat / quinoa.

[0028] Preferably, the mass percentage of Bacillus velezensis in the compound microbial inoculant is 5%, the mass percentage of Bacillus subtilis is 5%, the mass percentage of Pseudomonas qingdaonensis is 5%, the protein peptide powder is 10%, the mineral source fulvic acid potassium is 10%, and the molasses is 65%.

[0029] Preferably, the content of Bacillus velezensis is not less than 1×10 9 cfu / g, for example, it can be 2×10 9 ~3×1011 cfu / g; The content of Bacillus subtilis is not less than 1×10 9 cfu / g, for example, it can be 2×10 9 ~3×10 11 cfu / g; The content of Pseudomonas qingdaonensis is not less than 1×10 9 cfu / g, for example, it can be 2×10 9 ~3×10 11 cfu / g. The above uses cfu / g as the measurement unit of the solid bacterial agent. When it is a liquid bacterial agent, it is converted to cfu / mL, where 1 cfu / g = 1 cfu / mL.

[0030] In the present invention, there is no special limitation on the specific dosage of the bacterial agent, as long as it can play a role in promoting the resistance of tobacco seedlings to tobacco root-knot nematode disease.

[0031] In the present invention, there is no special limitation on the raw materials used as the above-mentioned bacterial agent. It can be any relevant product in the art that can be used to prepare the bacterial agent, either a commercially available relevant product or a relevant product prepared according to the existing technology.

[0032] In the present invention, the agronomic traits of tobacco plants include plant height, root length, maximum leaf length, maximum leaf width, stem girth, etc.; the physical properties of the soil include soil bulk density, total porosity, soil aggregate structure, soil saturated water holding capacity, capillary water holding capacity, and field water holding capacity, etc.; the chemical properties of the soil include pH, alkaline hydrolyzable nitrogen, available phosphorus, available potassium, exchangeable calcium, and exchangeable magnesium, etc.; the biological properties of the soil include the enzyme activities of soil urease, sucrase, acid phosphatase, catalase, peroxidase, etc.; soil phenolic acids include water-soluble phenols, complex phenols, and total phenols.

[0033] In the present invention, preventing and controlling tobacco root-knot nematode disease means reducing the disease index of tobacco root-knot nematode disease, or reducing the losses caused by the disease after the disease occurs, etc.

[0034] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the preferred embodiments of the present invention will be described in detail below to facilitate understanding by those skilled in the art.

[0035] In the present invention, Bacillus velezensis with the preservation number of CCTCC No. M2022923 has been disclosed in the Chinese invention patent with the publication number of: CN115572702 B.

[0036] In the present invention, Bacillus subtilis with the preservation number of CCTCC NO. M 20221207 has been disclosed in the Chinese invention patent with the publication number of CN115537363B.

[0037] In the present invention, Pseudomonas qingdaonensis with the preservation number of CCTCC No. M 2023153 has been disclosed in the Chinese invention patent with the publication number of CN117106614B.

[0038] To reduce repetition, the Bacillus velezensis mentioned in Examples 1 to 8 below specifically refers to: Bacillus velezensis with the preservation number of CCTCC No. M2022923; Bacillus subtilis specifically refers to: Bacillus subtilis with the preservation number of CCTCC No. M20221207; Pseudomonas qingdaonensis specifically refers to: Pseudomonas qingdaonensis with the preservation number of CCTCC No. M 2023153.

[0039] Example 1:

[0040] An integrated control method for tobacco root-knot nematode disease, comprising the following steps:

[0041] Step 1, Implement a two-year four-crop rotation planting system of tobacco and buckwheat in the plot for planting tobacco. In the first year: flue-cured tobacco - buckwheat → In the second year: flue-cured tobacco - buckwheat.

[0042] Step 2, Induce host resistance with microbial inoculum during the seedling stage. The compound microbial inoculum containing Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis includes protein peptide powder (purchased from Xi'an Allbio Biotechnology Co., Ltd., with a protein content of 98%), mineral source fulvic acid potassium (purchased from Shandong Pulan Biotechnology Co., Ltd., with a mineral source fulvic acid potassium content of 50%), and molasses (purchased from Jiangsu Jiujia Biotechnology Co., Ltd., with a molasses organic matter content of 75% and a nitrogen, phosphorus, and potassium content of 4%), as well as Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis, which contains the following components by mass fraction: protein peptide powder 10%, mineral source fulvic acid potassium 10%, molasses 65%, Bacillus velezensis 5%, Bacillus subtilis 5%, Pseudomonas qingdaonensis 5%; the content of Bacillus velezensis is 3×10 9 cfu / g, the content of Bacillus subtilis is 3×10 9 cfu / g, and the content of Pseudomonas qingdaonensis is 3×10 9 cfu / g. The application of the compound microbial inoculum in inducing host resistance with microbial inoculum during the seedling stage includes sowing after adding 1.0 kg of microbial inoculum to every cubic meter (m 3 ) of conventional seedling-raising substrate; applying 0.75 kg of the compound microbial inoculum per 100 square meters (m 2 ) when the 4th leaf of the tobacco seedlings grows; applying 0.75 kg of the compound microbial inoculum per 100 square meters (m 2 ) 7 days before transplanting; a total of 3 applications are made.

[0043] Step 3, improving the quality of tobacco-growing soil during the transplanting period. After harvesting the rotation crop buckwheat, the soil is deeply plowed by 35 cm, soaked in water for 8 days, and then sun-dried for 12 days. After applying 50 kg of soil conditioner per mu, tobacco is planted. The soil conditioner contains the following components by mass fraction: CaO 25%, MgO 16%, lime 56%, potassium phosphite 1%, copper sulfate 1%, zinc sulfate 0.5%, and ferrous sulfate 0.5%.

[0044] Example 2:

[0045] A comprehensive control method for tobacco root-knot nematode disease includes the following steps:

[0046] Step 1, implementing a two-year four-crop rotation system of tobacco and buckwheat in the tobacco-growing plot. In the first year: flue-cured tobacco - quinoa → In the second year: flue-cured tobacco - quinoa.

[0047] Step 2, inducing host resistance with microbial inoculants during the seedling stage. The composite microbial inoculant containing Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis includes protein peptide powder, mineral-source fulvic acid potassium, and molasses, as well as Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis. It contains the following components by mass fraction: protein peptide powder 10%, mineral-source fulvic acid potassium 10%, molasses 65%, Bacillus velezensis 5%, Bacillus subtilis 5%, and Pseudomonas qingdaonensis 5%; the content of Bacillus velezensis is 3×10 9 cfu / g, the content of Bacillus subtilis is 3×10 9 cfu / g, and the content of Pseudomonas qingdaonensis is 3×10 9 cfu / g. The application of the composite microbial inoculant in inducing host resistance with microbial inoculants during the seedling stage includes sowing after adding 0.5 kg of the microbial inoculant to every cubic meter (m 3 ) of conventional seedling-raising substrate; applying 0.5 kg of the composite microbial inoculant per 100 square meters (m 2 ) when the 4th leaf of the tobacco seedlings grows; applying 0.5 kg of the composite microbial inoculant per 100 square meters (m 2 ) 7 days before transplanting; a total of 3 applications are made.

[0048] Step 3, improving the quality of tobacco-growing soil during the transplanting period. After harvesting the rotation crop quinoa, the soil is deeply plowed by 30 cm, soaked in water for 7 days, and then sun-dried for 10 days. After applying 45 kg of soil conditioner per mu, tobacco is planted. The soil conditioner contains the following components by mass fraction: CaO 25%, MgO 16%, lime 56%, potassium phosphite 1%, copper sulfate 1%, zinc sulfate 0.5%, and ferrous sulfate 0.5%.

[0049] Example 3:

[0050] A comprehensive control method for tobacco root-knot nematode disease includes the following steps:

[0051] Step 1: Implement a two-year four-crop rotation planting system of tobacco and buckwheat in the tobacco-growing plot. In the first year: flue-cured tobacco - quinoa → In the second year: flue-cured tobacco - quinoa.

[0052] Step 2: Induce host resistance with microbial inoculants during the seedling stage. The compound microbial inoculant containing Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis includes protein peptide powder, mineral-source fulvic acid potassium, molasses, as well as Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis, and contains the following components by mass fraction: protein peptide powder 10%, mineral-source fulvic acid potassium 10%, molasses 65%, Bacillus velezensis 5%, Bacillus subtilis 5%, Pseudomonas qingdaonensis 5%; the content of Bacillus velezensis is 3×10 9 cfu / g, the content of Bacillus subtilis is 3×10 9 cfu / g, and the content of Pseudomonas qingdaonensis is 3×10 9 cfu / g. The application of the compound microbial inoculant in inducing host resistance with microbial inoculants during the seedling stage includes sowing after adding 1.0 kg of the microbial inoculant to every cubic meter (m 3 ) of conventional seedling-raising substrate, and applying it once in total.

[0053] Step 3: Improve the quality of the tobacco-planting soil during the transplanting period. After the rotation crop quinoa is harvested, the soil is deeply plowed by 40 cm, then flooded for 10 days, and then sun-dried for 15 days; 60 kg of soil conditioner is added per mu before planting tobacco. The soil conditioner contains the following components by mass fraction: CaO 25%, MgO 16%, lime 56%, potassium phosphite 1%, copper sulfate 1%, zinc sulfate 0.5%, and ferrous sulfate 0.5%.

[0054] Example 4:

[0055] A comprehensive control method for tobacco root-knot nematode disease, including the following steps:

[0056] Step 1: Implement a two-year four-crop rotation planting system of tobacco and buckwheat in the tobacco-growing plot. In the first year: flue-cured tobacco - quinoa → In the second year: flue-cured tobacco - quinoa.

[0057] Step 2: Induce host resistance with microbial inoculants during the seedling stage. The compound microbial inoculant containing Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis includes protein peptide powder, mineral-source fulvic acid potassium, molasses, as well as Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis, and contains the following components by mass fraction: protein peptide powder 10%, mineral-source fulvic acid potassium 10%, molasses 65%, Bacillus velezensis 5%, Bacillus subtilis 5%, Pseudomonas qingdaonensis 5%; the content of Bacillus velezensis is 3×10 9 cfu / g, the content of Bacillus subtilis is 3×10 9cfu / g, the content of Pseudomonas qingdaonensis is 3×10 9 cfu / g. The application of the compound microbial inoculant in inducing host resistance during the seedling stage includes applying 0.75 kg of the compound microbial inoculant per 100 square meters (m 2 ) when the fourth leaf of the tobacco seedling grows out; applying 0.75 kg of the compound microbial inoculant per 100 square meters (m 2 ) 7 days before transplanting; applying a total of 2 times.

[0058] Step 3, improving the quality of the tobacco-planting soil during the transplanting period. After the rotation crop buckwheat is harvested, the soil is deeply plowed by 35 cm, then flooded for 8 days, and then sun-dried for 12 days; 50 kg of soil conditioner is applied per mu before planting tobacco. The soil conditioner contains the following components by mass fraction: CaO 25%, MgO 16%, lime 56%, potassium phosphite 1%, copper sulfate 1%, zinc sulfate 0.5% and ferrous sulfate 0.5%.

[0059] Example 5:

[0060] A comprehensive control method for tobacco root-knot nematode disease includes the following steps:

[0061] Step 1, implementing a two-year four-crop rotation planting system of tobacco and buckwheat in the tobacco-planting plot. In the first year: flue-cured tobacco - buckwheat → In the second year: flue-cured tobacco - buckwheat.

[0062] Step 2, inducing host resistance with microbial inoculant during the seedling stage. The compound microbial inoculant containing Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis includes protein peptide powder, mineral-source fulvic acid potassium, and molasses, as well as Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis, and contains the following components by mass fraction: protein peptide powder 10%, mineral-source fulvic acid potassium 10%, molasses 65%, Bacillus velezensis 5%, Bacillus subtilis 5%, Pseudomonas qingdaonensis 5%; the content of Bacillus velezensis is 3×10 9 cfu / g, the content of Bacillus subtilis is 3×10 9 cfu / g, the content of Pseudomonas qingdaonensis is 3×10 9 cfu / g. The application of the compound microbial inoculant in inducing host resistance during the seedling stage includes sowing after adding 1.0 kg of the microbial inoculant to each cubic meter (m 3 ) of the conventional seedling-raising substrate; applying 0.75 kg of the compound microbial inoculant per 100 square meters (m 2 ) when the fourth leaf of the tobacco seedling grows out; applying 0.75 kg of the compound microbial inoculant per 100 square meters (m 2 ) 7 days before transplanting; applying a total of 3 times.

[0063] Step 3, improvement of the soil quality for tobacco planting during the transplanting period. After the rotation crop buckwheat is harvested, the soil is deeply plowed by 35 cm, soaked with water for 8 days, and then sun-dried for 12 days.

[0064] Example 6:

[0065] A comprehensive control method for tobacco root-knot nematode disease, comprising the following steps:

[0066] Step 1, implement a two-year four-crop rotation planting system of tobacco and buckwheat in the tobacco planting plot. In the first year: flue-cured tobacco - buckwheat → In the second year: flue-cured tobacco - buckwheat.

[0067] Step 2, induce host resistance with microbial inoculum during the seedling stage. The compound microbial inoculum containing Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis includes protein peptide powder, mineral source fulvic acid potassium, molasses, as well as Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis, and contains the following components in mass fractions: 10% of protein peptide powder, 10% of mineral source fulvic acid potassium, 65% of molasses, 5% of Bacillus velezensis, 5% of Bacillus subtilis, and 5% of Pseudomonas qingdaonensis; the content of Bacillus velezensis is 3×10 9 cfu / g, the content of Bacillus subtilis is 3×10 9 cfu / g, and the content of Pseudomonas qingdaonensis is 3×10 9 cfu / g. The application of the compound microbial inoculum to induce host resistance with microbial inoculum during the seedling stage includes sowing after adding 1.0 kg of the microbial inoculum to every cubic meter (m 3 ) of conventional seedling-raising substrate; applying 1 kg of the compound microbial inoculum per 100 square meters (m 2 ) when the 4th leaf of the tobacco seedling grows; applying 1 kg of the compound microbial inoculum per 100 square meters (m 2 ) 7 days before transplanting; a total of 3 applications are made.

[0068] Step 3, improvement of the soil quality for tobacco planting during the transplanting period. After the rotation crop buckwheat is harvested, apply 50 kg of soil conditioner per mu and then plant tobacco. The soil conditioner contains the following components in mass fractions: 25% of CaO, 16% of MgO, 56% of lime, 1% of potassium phosphite, 1% of copper sulfate, 0.5% of zinc sulfate, and 0.5% of ferrous sulfate.

[0069] Example 7:

[0070] A comprehensive control method for tobacco root-knot nematode disease, comprising the following steps:

[0071] Step 1, implement a two-year four-crop rotation planting system of tobacco and buckwheat in the tobacco planting plot. In the first year: flue-cured tobacco - buckwheat → In the second year: flue-cured tobacco - buckwheat.

[0072] Step 2, inducing host resistance by microbial inoculant during the seedling stage. The compound microbial inoculant containing Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis includes protein peptide powder, mineral-source fulvic acid potassium, molasses, as well as Bacillus velezensis, Bacillus subtilis, and Pseudomonas qingdaonensis, and contains the following components by mass fraction: protein peptide powder 10%, mineral-source fulvic acid potassium 10%, molasses 65%, Bacillus velezensis 5%, Bacillus subtilis 5%, Pseudomonas qingdaonensis 5%; the content of Bacillus velezensis is 3×10 9 cfu / g, the content of Bacillus subtilis is 3×10 9 cfu / g, and the content of Pseudomonas qingdaonensis is 3×10 9 cfu / g. The application of the compound microbial inoculant in inducing host resistance by microbial inoculant during the seedling stage includes sowing after adding 1.0 kg of the microbial inoculant to every cubic meter (m 3 ) of conventional seedling-raising substrate; applying 0.75 kg of the compound microbial inoculant per 100 square meters (m 2 ) when the 4th leaf of the tobacco seedlings grows; applying 0.75 kg of the compound microbial inoculant per 100 square meters (m 2 ) 7 days before transplanting; and applying it 3 times in total.

[0073] Example 8:

[0074] An integrated control method for tobacco root-knot nematode disease includes the following steps:

[0075] Step 1, implementing a two-year four-crop rotation planting system of tobacco and buckwheat in the plot for planting tobacco. In the first year: flue-cured tobacco - buckwheat → In the second year: flue-cured tobacco - buckwheat.

[0076] Step 2, improving the quality of the tobacco-planting soil during the transplanting period. After the rotation crop buckwheat is harvested, the soil is deeply plowed by 35 cm, then flooded for 8 days, and then sun-dried for 12 days; 50 kg of soil conditioner is applied per mu before planting tobacco. The soil conditioner contains the following components by mass fraction: CaO 25%, MgO 16%, lime 56%, potassium phosphite 1%, copper sulfate 1%, zinc sulfate 0.5%, and ferrous sulfate 0.5%.

[0077] Comparative Example 1:

[0078] According to the method of Example 1, the difference is that tobacco is continuously cropped without rotation with any crops.

[0079] Comparative Example 2:

[0080] According to the method of Comparative Example 1, the difference is that continuous cropping of tobacco is replaced by continuous cropping of potatoes.

[0081] Comparative Example 3:

[0082] According to the method of Comparative Example 1, the difference is that the microbial inoculum for inducing host resistance in the seedling raising stage of Step 2 is not used.

[0083] Comparative Example 4:

[0084] According to the method of Comparative Example 1, the difference is that the improvement of the quality of tobacco-growing soil in the transplanting stage of Step 3 is not used. Comparative Example 5:

[0085] According to the method of Comparative Example 1, the difference is that the microbial inoculum for inducing host resistance in the seedling raising stage of Step 2 is not used, and the improvement of the quality of tobacco-growing soil in the transplanting stage of Step 3 is not used.

[0086] Test Example:

[0087] The effects of the present invention will be further described below in combination with the application of the present method in tobacco cultivation. The specific test process and results are as follows.

[0088] The methods in the above-mentioned examples and comparative examples were used in the entire processes of the seedling raising stage, transplanting stage, and field stage of tobacco. On the 30th day after emergence, 10 tobacco seedlings with uniform growth vigor were selected to measure the agronomic traits; at the harvest stage, the physical and chemical indexes of the soil were analyzed and tested, the disease incidence was investigated, and the control effect was calculated.

[0089] The soil water holding capacity and porosity were measured by the cutting ring method: A cutting ring with a standard volume of 100 cm 3 was used, and its weight was recorded as M0; the cutting ring with the weighed mass was vertically pressed into the PVC container so that the cutting ring was filled with soil. Without damaging the soil inside the cutting ring, the cutting ring was taken out, and the soil exposed at both ends of the cutting ring was shaved off with a small knife. After wiping off the soil remaining outside the cutting ring, a lid was immediately covered to prevent water evaporation. The cutting ring containing the soil was placed in a flat-bottomed PVC container with the perforated lid facing downwards, and water was slowly added to keep the water surface about 1 mm lower than the upper edge of the cutting ring, and it was soaked overnight to make the soil fully absorb water to saturation. The cutting ring was taken out and weighed and recorded as M1; then it was placed in a flat-bottomed container paved with dry sand, with a coarse filter paper placed below. After a 2-hour infiltration process, it was taken out and weighed and recorded as M2; then it was placed on the dry sand (also with a coarse filter paper placed) and continued to infiltrate for 6 hours, and then taken out and weighed and recorded as M3; finally, it was dried to a constant weight in an oven at 110 °C, taken out and weighed and recorded as M4. The specific index calculations are as follows:

[0090] Bulk density (g / cm 3 ) = (M4 - M0) / 100

[0091] Saturated water holding capacity (%) = (M1 - M4) / (M4 - M0) × 100%

[0092] Capillary water holding capacity (%) = (M2 - M4) / (M4 - M0) × 100%

[0093] Field water holding capacity (%) = (M3 - M4) / (M4 - M0) × 100%

[0094] Capillary porosity (%) = Capillary water holding capacity × Bulk density

[0095] Non - capillary porosity (%) = (Saturation water holding capacity - Capillary water holding capacity) × Bulk density

[0096] Total porosity (%) = Capillary porosity + Non - capillary porosity

[0097] The dry - sieving method was used for soil aggregate classification. That is, the soil remaining in the PVC container after cutting the core sampler was taken out, air - dried indoors naturally, and gently broken into soil clods with a diameter of about 1 cm according to the natural structure of the soil sample. Plant residues, stones and other sundries were removed. 100 g of air - dried soil was placed in five nested sieves with pore sizes of 5 mm, 2 mm, 1 mm, 0.5 mm and 0.25 mm from top to bottom. The electric sieve shaker (model 8411, China) was started, and after shaking for 10 minutes, the soil weights (m) of each layer of the nested sieves were weighed and recorded, and six - level soil aggregates of >5 mm, 2 - 5 mm, 1 - 2 mm, 0.5 - 1 mm, 0.25 - 0.5 mm and <0.25 mm were separated. The specific calculation indexes are as follows in the formula:

[0098] Proportion of each - level soil aggregate (%) = m / 100 g × 100%

[0099] Soil pH was determined by the potentiometric method, alkaline hydrolyzable nitrogen was determined by the diffusion method, available phosphorus was determined by the sodium bicarbonate method, available potassium was determined by the flame photometry method, exchangeable calcium and exchangeable magnesium were determined by the atomic absorption spectrophotometry method.

[0100] Soil urease activity was determined by the phenol - sodium hypochlorite colorimetric method, soil acid phosphatase activity was determined by the disodium phenyl phosphate colorimetric method, soil invertase activity was determined by the 3,5 - dinitrosalicylic acid colorimetric method; catalase activity was determined by the potassium permanganate titration method, peroxidase activity was determined by the purpurogallin colorimetric method.

[0101] Soil phenolic acids were determined by ASE - HPLC method.

[0102] Investigation and calculation method of disease index:

[0103] Investigation and grading standard for tobacco root - knot nematode disease: Grade 0: No galls on the roots; Grade 1: A small number of small galls on the roots; Grade 3: Two - thirds of the roots are covered with small galls; Grade 5: The roots are covered with small galls and have secondary galls; Grade 7: The roots form fibrous root masses.

[0104] Disease index = [∑(Number of diseased plants at each level × Representative value of each level) / (Total number of plants investigated × Representative value of the highest level)] × 100

[0105] Table 1. Test Conditions and Results of the Disease Index of Root-knot Nematode under Different Treatments

[0106]

[0107] Table 2. Test Conditions and Results of the Agronomic Traits of Tobacco Seedlings under Different Treatments

[0108]

[0109] Table 3. Test Conditions and Results of the Physical Properties of Tobacco-growing Soil at the Harvesting Stage under Different Treatments

[0110]

[0111] Table 4. Test Conditions and Results of the Chemical Properties of Tobacco-growing Soil under Different Treatments

[0112]

[0113] Table 5. Test Conditions and Results of the Biological Properties of Tobacco-growing Soil under Different Treatments

[0114]

[0115] Table 6. Test Conditions and Results of the Phenolic Acid Content in Tobacco under Different Treatments

[0116]

[0117] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A comprehensive control method for tobacco root-knot nematode disease, characterized in that: The following steps are involved: Step 1: The tobacco and buckwheat fields are planted with a two-year four-crop rotation system. The first year: flue-cured tobacco - quinoa → the second year: flue-cured tobacco - quinoa; Step 2, inducing host resistance with a microbial agent during the seedling period, the composite microbial agent containing Bacillus velezii, Bacillus subtilis and Pseudomonas Qingdao includes protein peptide powder, mineral potassium humate and molasses, and Bacillus velezii, Bacillus subtilis and Pseudomonas Qingdao, wherein the components are as follows by mass fraction: protein peptide powder 10%, mineral potassium humate 10%, molasses 65%, Bacillus velezii 5%, Bacillus subtilis 5%, Pseudomonas Qingdao 5%; Bacillus velezii content 3×10 9 cfu / g, and the content of Bacillus subtilis was 3×10 9 cfu / g, the content of Pseudomonas Qingdaoensis was 3×10 9 cfu / g; The application of compound microbial agents to induce host resistance during the seedling stage includes per cubic meter (m 3 ) Add 0.5 kg of microbial agent to conventional seedling medium before sowing; when the fourth leaf of tobacco seedling grows out, add 0.5 kg of microbial agent to conventional seedling medium before sowing; when the fourth leaf of tobacco seedling grows out, add 0.5 kg of microbial agent to conventional seedling medium after ... 2 ) Apply 0.5 kg of compound microbial agent; 7 days before transplanting, per 100 square meters (m 2 ) Apply 0.5 kg of compound microbial agent for 3 times in total; Step 3, improving the quality of tobacco-planting soil during the transplanting period, after the rotation crop quinoa is harvested, the soil is plowed to a depth of 30 cm, then soaked in water for 7 days, and then turned over and dried for 10 days; 45 kg of soil conditioner is added per mu before planting tobacco; the soil conditioner contains the following components in mass fraction: CaO 25%, MgO 16%, lime 56%, potassium phosphite 1%, copper sulfate 1%, zinc sulfate 0.5% and ferrous sulfate 0.5%.

2. A method according to claim 1, characterized in that: The tobacco root knot nematode disease is southern root knot nematode (Meloidogyne incognita) disease.

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