A kind of anti-nematode liquid fungal agent and its application

Abstract

A liquid anti-nematode fungal agent and its application, the preparation method of which is as follows: it is made of Aspergillus niger J6 liquid fungal agent and functional additives; the activated Aspergillus niger J6 strain is rinsed with PDA liquid culture medium to obtain a spore suspension, which is then cultured in a PDA liquid culture medium to obtain a first-level seed liquid; the liquid culture medium is prepared, loaded into a fermentation tank, sterilized at high temperature, and cooled to obtain a fermentation medium; the first-level seed liquid is inoculated into a seed fermentation tank filled with a fermentation medium to obtain a second-level seed liquid, which is then transferred to another large fermentation tank for fermentation culture and then packaged; sampling and testing are performed regularly during the fermentation process, and the finished product of the liquid anti-nematode fungal agent is obtained after it meets the national standard. The preparation method is easy to operate, and the raw materials are abundant. It can be effectively used to prepare the liquid anti-nematode agent required for crops, and applied as fertilizer to crops, especially melons, lettuce, cherry tomatoes, etc., which can effectively prevent nematode diseases and ensure a bumper harvest of crops, with huge economic and social benefits.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural microorganisms, and in particular to an anti-nematode liquid fungal agent and application thereof. Background Art

[0002] Root-knot nematode disease is a soil-borne disease caused by root-knot nematodes that seriously harms the root system of plants. The disease causes huge economic losses to crops worldwide and is one of the important factors that seriously restrict agricultural development. In recent years, the occurrence of root-knot nematode disease in greenhouse vegetables has been increasing, which has seriously affected the yield, quality, commerciality and safety of greenhouse vegetables, causing great economic losses to farmers. At present, the prevention and control of root-knot nematodes is still mainly chemical control. The earliest fumigation chemical agents used to prevent and control root-knot nematodes are methyl bromide, chloropicrin and DD mixture. Although fumigation nematicides have a thorough nematicidal effect and are not easy to induce nematode resistance, fumigation nematicides are harmful to growing crops and seed buds. The use time is limited and can only be used two weeks before sowing. At the same time, the use of fumigation nematicides will affect the natural enemies of plant parasitic nematodes and other organisms that are beneficial to the soil ecological environment, and even kill them, which is not conducive to soil activation, natural enemy reproduction and continuous ecological regulation, and has side effects on environmental protection. Some varieties can affect fertility and even have carcinogenic effects, posing a serious threat to humans. In 1956, the non-fumigant organophosphorus nematicide chloranthate was first introduced. Later, non-fumigants such as chloranthate, chloranthate, aldicarb, chloranthate, chloranthate, and methyl isoflavone gradually appeared. Among them, chloranthate, chloranthate, and aldicarb belong to carbamate. At present, the nematicides commonly used at home and abroad include Wanqiang, chloranthate, dazomethane, chloranthate, and dithiocyanate. The commonly used non-fumigant nematicides include Lilimanku Granules, chloranthate, Wanqiang, chloranthate, aldicarb, and chloranthate. The advantages of non-fumigant nematicides are less pesticide damage and significant yield increase effects. However, its mode of action determines that its insecticidal effect is not as ideal as that of fumigant nematicides. At the same time, it may also cause nematodes to develop drug resistance. In addition, the toxicity of non-fumigant nematicides is relatively high, and they must generally be discontinued 40 days before harvest. The most important thing is that the use of pesticides not only cannot completely eliminate root-knot nematodes from the soil, but also leads to soil ecological imbalance and more serious crop diseases and insect pests. The negative impact of highly toxic chemical nematicides on human health and the ecological environment is becoming increasingly prominent. Therefore, green and pollution-free microbial control has gradually attracted people's attention.

[0003] At present, most of the microbial agents on the market in my country are powder products. During use, due to the small particles, they are easy to float and difficult to operate. In addition, the existing microbial products for controlling root-knot nematodes have problems such as poor prevention effect, low utilization rate, poor specificity, and short shelf life. Therefore, it is urgent to develop a high-efficiency functional microbial agent that is easy to produce, store and transport, and is conducive to the application of facility agriculture. Summary of the invention

[0004] In view of the above situation, in order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide an anti-nematode liquid fungal agent and its application, which can effectively prevent and control fruit and vegetable nematode diseases and is easy to produce, store, transport and use.

[0005] To achieve the above object, the technical solution provided by the present invention is a liquid anti-nematode fungal agent, which is made of 99.5-99.9% Aspergillus niger J6 liquid agent and 0.1-0.5% functional additive in volume ratio; the functional additive is a sterilized glycerol, Tween-20 or xanthan gum with a volume concentration of 50%, one, two or three of which are uniformly mixed;

[0006] The preparation method of the microbial agent is:

[0007] (1) Strain activation

[0008] The preserved Aspergillus niger J6 strain was transferred to a slant plate of PDA medium and cultured in a 30° C. incubator for 4 to 5 days until the black spores covered the entire plate, thus completing the activation of the Aspergillus niger J6 strain;

[0009] The Aspergillus niger J6 is classified and named as Aspergillus niger, and was deposited in the General Microbiology Center of China Microorganism Culture Collection Committee on October 12, 2010, with the deposit number of CGMCC No.4220, and the address is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing;

[0010] The PDA medium is prepared by adding distilled water to 200g of potato, 20g of glucose, 15-20g of agar, and the method is as follows: first weigh 200g of potato, wash and peel, cut into small pieces, add distilled water and boil for 20-30min, filter, heat, add 15-20g of agar, continue heating and stirring to mix, add glucose after the agar is dissolved, stir evenly, add distilled water to 1000mL, sterilize at 115℃ for 20min, and cool to room temperature.

[0011] (2) Preparation of primary seed solution:

[0012] Use a pipette to draw 5 mL of PDA liquid medium to wash the black spores on the plate, and use a cell counting plate to determine the spore concentration. 7 CFU / mL, and obtain a spore suspension; then take 2mL of the spore suspension and inoculate it into PDA liquid culture medium, and culture it in a shaking incubator at 25-30℃ and 180r / min for 12-24h, and after the spores germinate, obtain the first-level seed solution;

[0013] (3) Preparation of fermentation medium:

[0014] Weigh and prepare liquid culture medium according to the basic salt-glucose culture medium formula, put it into the fermentation tank, sterilize it under high pressure at 115℃~121℃ for 20~30min, and cool it for use;

[0015] The basic salt culture medium formula is NaCL 1g, KH2PO4 0.5g, K2HPO4 1.5g, (NH4)2SO4 1g, MgSO4·7H2O 0.1g, glucose 2g, fixed volume to 1000mL, pH 7.0;

[0016] (4) Preparation of secondary seed solution:

[0017] The first-level seed liquid is inoculated into a seed fermentation tank filled with the fermentation medium at an inoculation amount of 5-10% of the volume of the fermentation medium, and cultured at 25-30° C. and 30 Hz shaking for 12-48 hours to obtain the second-level seed liquid.

[0018] (5) Fermentation: The secondary seed liquid is then transferred to another large fermentation tank with a capacity of more than 1000 L for fermentation culture at 25 to 30° C. and 30 Hz shaking for 24 to 48 hours to obtain Aspergillus niger J6 liquid inoculant;

[0019] (6) Preparation of finished microbial agent: Add 0.1-0.5% functional additive to the Aspergillus niger J6 liquid microbial agent, stir well, take samples, and test according to the national standard GB20287-2006. If the effective viable count reaches more than 500 million / mL, the pH value is 5.0-6.0, and the rate of foreign bacteria is ≤1%, it is the finished anti-nematode liquid fungal agent, which is then canned and packaged for later use.

[0020] The invention discloses an application of the anti-nematode liquid fungal agent in preventing and treating nematode diseases of fruits and vegetables.

[0021] The fruits and vegetables are crops such as melons, cherry tomatoes, and lettuce.

[0022] The present invention provides an anti-nematode liquid fungal agent, which has a novel and unique preparation method, low production cost, easy operation and convenient application. The liquid fungal agent not only has a long shelf life, but is also easy to promote and apply in facility agriculture, can effectively prevent fruit and vegetable nematode diseases, especially has a significant preventive effect on root-knot nematode diseases of melons, lettuce, cherry tomatoes and other fruit and vegetable crops, has a significant effect of promoting growth, increasing production and improving soil, ensures a bumper harvest of crops, and has huge economic and social benefits. DETAILED DESCRIPTION

[0023] The specific implementation modes of the present invention are described in detail below in combination with embodiments and specific situations.

[0024] Embodiment 1:

[0025] An anti-nematode liquid fungal agent is prepared by mixing 99.9% of Aspergillus niger J6 liquid agent and 0.1% of 50% sterilized glycerol in a volume ratio. The preparation method is as follows:

[0026] (1) Strain activation

[0027] The preserved Aspergillus niger J6 strain was transferred to a slant plate of PDA medium and cultured in a 30° C. incubator for 4 days until the black spores covered the entire plate, completing the activation of the Aspergillus niger J6 strain;

[0028] (2) Preparation of primary seed solution

[0029] Use a pipette to draw 5 mL of PDA liquid medium to wash the black spores on the plate, and use a cell counting plate to determine the spore concentration. 7 CFU / mL, and obtain a spore suspension; then take 2mL of the spore suspension and inoculate it into PDA liquid culture medium, and culture it in a shaking incubator at 30℃ and 180r / min for 12h. After the spores germinate, obtain the first-level seed solution;

[0030] (3) Preparation of fermentation medium:

[0031] Weigh and prepare liquid culture medium according to the basic salt-glucose culture medium formula, put it into the fermentation tank, sterilize it at 115℃ for 20min, and cool it for use;

[0032] (4) Preparation of secondary seed solution:

[0033] Inoculate the first-level seed solution in a seed fermentation tank filled with the fermentation medium at an inoculation rate of 10% of the volume of the fermentation medium, and culture at 30° C. and 30 Hz with shaking for 12 hours to obtain the second-level seed solution;

[0034] (5) Fermentation: The secondary seed liquid is then transferred to another large fermentation tank (more than 1000 L) for fermentation culture at 25° C. and 30 Hz shaking for 48 h to obtain Aspergillus niger J6 liquid inoculant;

[0035] (6) Preparation of finished microbial agent: Add 0.1% of 50% sterilized glycerol to the Aspergillus niger J6 liquid microbial agent, stir thoroughly, take samples, and test according to the national standard GB20287-2006. If the effective viable count reaches more than 500 million / mL, the pH value is 5.0-6.0, and the rate of foreign bacteria is ≤1%, it is the finished anti-nematode liquid fungal agent, which is then canned and packaged for later use.

[0036] Embodiment 2:

[0037] An anti-nematode liquid fungal agent is prepared by mixing 99.9% of Aspergillus niger J6 liquid fungal agent and 0.1% of Tween-20 in a volume ratio. The preparation method is as follows:

[0038] (1) Strain activation

[0039] The preserved Aspergillus niger J6 strain was transferred to a slant plate of PDA medium and cultured in a 30° C. incubator for 4 days until the black spores covered the entire plate, completing the activation of the Aspergillus niger J6 strain;

[0040] (2) Preparation of primary seed solution

[0041] Use a pipette to draw 5 mL of PDA liquid medium to wash the black spores on the plate, and use a cell counting plate to determine the spore concentration. 7 CFU / mL, and obtain a spore suspension; then take 2mL of the spore suspension and inoculate it into PDA liquid culture medium, and culture it in a shaking incubator at 25°C and 180r / min for 24h. After the spores germinate, obtain the primary seed solution;

[0042] (3) Preparation of fermentation medium:

[0043] Weigh and prepare liquid culture medium according to the basic salt-glucose culture medium formula, put it into the fermentation tank, sterilize it at 115℃ for 30min, and cool it for use;

[0044] (4) Preparation of secondary seed solution:

[0045] Inoculate the first-level seed liquid in a seed fermentation tank filled with the above fermentation medium at an inoculation rate of 5% of the volume of the fermentation medium, and culture at 30° C. and 30 Hz with shaking for 12 hours to obtain the second-level seed liquid;

[0046] (5) Fermentation: The secondary seed liquid is then transferred to another large fermentation tank (more than 1000 L) for fermentation culture at 25° C. and 30 Hz shaking for 48 h to obtain Aspergillus niger J6 liquid inoculant;

[0047] (6) Preparation of finished microbial agent: Add 0.1% Tween-20 to the Aspergillus niger J6 liquid microbial agent, stir thoroughly, take samples, and test according to the national standard GB20287-2006. If the effective viable count reaches more than 500 million / mL, the pH value is 5.0-6.0, and the rate of foreign bacteria is ≤1%, it is the finished anti-nematode liquid fungal agent, which is then canned and packaged for later use.

[0048] Embodiment 3:

[0049] An anti-nematode liquid fungal agent is prepared by mixing 99.9% of Aspergillus niger J6 liquid fungal agent and 0.1% of xanthan gum in a volume ratio, and the preparation method thereof is as follows:

[0050] (1) Strain activation

[0051] The preserved Aspergillus niger J6 strain was transferred to a slant plate of PDA medium and cultured in a 30° C. incubator for 5 days until the black spores covered the entire plate, completing the activation of the Aspergillus niger J6 strain;

[0052] (2) Preparation of primary seed solution

[0053] Use a pipette to draw 5 mL of PDA liquid medium to wash the black spores on the plate, and use a cell counting plate to determine the spore concentration. 7 CFU / mL, and obtain spore suspension; then take 2mL of spore suspension and inoculate into PDA liquid culture medium, and culture at 30℃, 180r / min shaking table for 16h, and after spore germination, obtain primary seed liquid;

[0054] (3) Preparation of fermentation medium:

[0055] Weigh and prepare liquid culture medium according to the basic salt-glucose culture medium formula, put it into the fermentation tank, sterilize it at 121℃ for 20min, and cool it for use;

[0056] (4) Preparation of secondary seed solution:

[0057] Inoculate the first-level seed liquid in a seed fermentation tank filled with the above fermentation medium at an inoculation rate of 8% of the volume of the fermentation medium, and culture at 28° C. and 30 Hz shaking for 48 hours to obtain the second-level seed liquid;

[0058] (5) Fermentation: The secondary seed liquid is then transferred to another large fermentation tank (more than 1000 L) for fermentation culture at 28° C. and 30 Hz shaking for 36 h to obtain Aspergillus niger J6 liquid inoculant;

[0059] (6) Preparation of finished microbial agent: Add 0.1% xanthan gum to the Aspergillus niger J6 liquid microbial agent, stir thoroughly, take samples, and test according to the national standard GB20287-2006. If the effective viable count reaches more than 500 million / mL, the pH value is 5.0-6.0, and the rate of foreign bacteria is ≤1%, it is the finished anti-nematode liquid fungal agent, which is then canned and packaged for later use.

[0060] Embodiment 4:

[0061] An anti-nematode liquid fungal agent is prepared by uniformly mixing 99.5% of Aspergillus niger J6 liquid agent and 0.5% of a mixed solution of 50% glycerol, Tween-20 and xanthan gum in a volume ratio. The preparation method is as follows:

[0062] (1) Strain activation

[0063] The preserved Aspergillus niger J6 strain was transferred to a slant plate of PDA medium and cultured in a 30° C. incubator for 4 days until the black spores covered the entire plate, completing the activation of the Aspergillus niger J6 strain;

[0064] (2) Preparation of primary seed solution

[0065] Use a pipette to draw 5 mL of PDA liquid medium to wash the black spores on the plate, and use a cell counting plate to determine the spore concentration. 7 CFU / mL, and obtain a spore suspension; then take 2mL of the spore suspension and inoculate it into PDA liquid culture medium, and culture it in a shaking incubator at 28℃ and 180r / min for 24h. After the spores germinate, obtain the first-level seed solution;

[0066] (3) Preparation of fermentation medium

[0067] Weigh and prepare liquid culture medium according to the basic salt-glucose culture medium formula, put it into the fermentation tank, sterilize it at 121℃ for 20min, and cool it for use;

[0068] (4) Preparation of secondary seed solution:

[0069] Inoculate the first-level seed liquid in a seed fermentation tank filled with the fermentation medium at an inoculation rate of 5-10% of the volume of the fermentation medium, and culture at 25° C. and 30 Hz shaking for 24 hours to obtain the second-level seed liquid;

[0070] (5) Fermentation: The secondary seed liquid is then transferred to another large fermentation tank (more than 1000 L) for fermentation culture at 30° C. and 30 Hz shaking for 24 h to obtain Aspergillus niger J6 liquid inoculant;

[0071] (6) Preparation of finished microbial agent: Add 0.5% of 50% glycerol, Tween-20 and xanthan gum mixture to Aspergillus niger J6 liquid microbial agent, stir thoroughly, take samples, and test according to the national standard GB20287-2006. If the effective viable count reaches more than 500 million / mL, the pH value is 5.0-6.0, and the rate of foreign bacteria is ≤1%, it is the finished anti-nematode liquid fungal agent, which is then canned and packaged for later use.

[0072] Embodiment 5:

[0073] An anti-nematode liquid fungal agent is prepared by uniformly mixing 99.7% of Aspergillus niger J6 liquid agent and 0.3% of a 50% glycerol and Tween-20 mixed solution in a volume ratio. The preparation method is as follows:

[0074] (1) Strain activation

[0075] The preserved Aspergillus niger J6 strain was transferred to a slant plate of PDA medium and cultured in a 30° C. incubator for 4.5 days until the black spores covered the entire plate, thus completing the activation of the Aspergillus niger J6 strain;

[0076] (2) Preparation of primary seed solution

[0077] Use a pipette to draw 5 mL of PDA liquid medium to wash the black spores on the plate, and use a cell counting plate to determine the spore concentration. 7CFU / mL, and obtain spore suspension; then take 2mL of spore suspension and inoculate into PDA liquid culture medium, and culture it in a shaking incubator at 28℃ and 180r / min for 20h, and after spore germination, obtain the primary seed liquid;

[0078] (3) Preparation of fermentation medium

[0079] Weigh and prepare liquid culture medium according to the basic salt-glucose culture medium formula, put it into the fermentation tank, sterilize it at 121℃ for 20min, and cool it for use;

[0080] (4) Preparation of secondary seed solution:

[0081] Inoculate the first-level seed liquid in a seed fermentation tank filled with the fermentation medium at an inoculation rate of 5-10% of the volume of the fermentation medium, and culture at 28° C. and 30 Hz shaking for 20 hours to obtain the second-level seed liquid;

[0082] (5) Fermentation: The secondary seed liquid is then transferred to another large fermentation tank (more than 1000 L) for fermentation culture at 30° C. and 30 Hz shaking for 36 h to obtain Aspergillus niger J6 liquid inoculant;

[0083] (6) Preparation of finished microbial agent: Add 0.3% of a mixture of 50% glycerol and Tween-20 to the Aspergillus niger J6 liquid microbial agent, stir thoroughly, take samples, and test according to the national standard GB20287-2006. If the effective viable count reaches more than 500 million / mL, the pH value is 5.0-6.0, and the rate of foreign bacteria is ≤1%, it is the finished anti-nematode liquid fungal agent, which is then canned and packaged for later use.

[0084] The invention discloses an application of the anti-nematode liquid fungal agent in preventing and controlling nematode diseases of fruits and vegetables.

[0085] The fruits and vegetables are crops such as melon, lettuce, and cherry tomatoes.

[0086] According to the bacterial agent given in the above embodiment, any amount of bacterial agent can be prepared according to needs. The given embodiment is only used to illustrate the specific implementation mode of the present invention, rather than to limit the protection scope of the present invention. The technical core protected by the present invention is the bacterial agent, and the bacterial agent can be prepared in any amount according to actual needs.

[0087] The anti-nematode liquid fungal agent provided by the present invention can be effectively applied to crops, especially melons, lettuces, cherry tomatoes, etc., and has a significant effect in preventing and controlling root-knot nematode diseases of fruits and vegetables, which can ensure a high yield and harvest of crops. The test results show that the anti-nematode liquid fungal agent has a very good beneficial technical effect. The relevant materials are as follows:

[0088] 1. Quality inspection:

[0089] The specific results of the quality test of the anti-nematode liquid fungal agent provided by the present invention are compared with the national standard. From Table 1, it can be seen that the product quality is better than the requirements specified in the national standard GB20287-2006.

[0090] Table 1 Comparison of test results of anti-nematode liquid fungal agent products and national standards

[0091]

[0092] 2. Experiment on the application effect of crops (taking Example 1 as an example)

[0093] Experiment 1: Application effect test on cherry tomatoes

[0094] 1. Materials and methods

[0095] 1.1 Test materials

[0096] In March 2021, the experiment was arranged in a tomato vegetable greenhouse in Henan. The experimental field has convenient transportation, easy observation and management, square plots, flat terrain, uniform fertility, convenient drainage and irrigation, high planting production level, and consistent previous crops. The test soil is loam. The nutrients of the plough layer soil are: organic matter 6.26%, hydrolyzed nitrogen 303.33mg / kg, available phosphorus 316.74mg / kg, and available potassium 401mg / kg.

[0097] The test crop was cherry tomato, and the variety was Shengtao No. 6.

[0098] The test fertilizer is the anti-nematode liquid fungal agent of the present invention (effective live bacteria count ≥ 200 million / g), which is provided by the Biological Research Institute Co., Ltd. of Henan Academy of Sciences.

[0099] 1.2 Test methods

[0100] This experiment has 4 treatments, arranged in random blocks, repeated three times, and the area of ​​the plot is 50m 2 .

[0101] Treatment 1: Blank control

[0102] Treatment 2: Fermentation medium of the anti-nematode liquid fungal agent of the present invention 5 L / mu

[0103] Treatment 3: 5 L / mu of the anti-nematode liquid fungal agent of the present invention

[0104] Treatment 4: 0.5% avermectin granules 3.3 kg / mu

[0105] The experiment was strictly divided into plots according to the requirements of the plan. The plots were irrigated in single rows to avoid cross-irrigation and cross-rowing. The plants in the plots were drip-irrigated according to the experimental design dosage. After transplanting, continuous drip irrigation was used twice, with an interval of 7 days each time. 1 ton of fermented chicken manure and 80 kg of compound fertilizer (N: P: K = 17: 17: 17) were used as base fertilizer per mu. 10 kg of water-soluble fertilizer (N: P: K = 20: 20: 20) was applied during the fruit setting period, and 10 kg of water-soluble fertilizer containing 36% potassium oxide was applied during the fruit swelling period. On March 13, 2022, tomato seedlings were planted, with 30 seedlings per treatment and a planting density of 2,000 plants per mu; film was covered on March 12; the first vine adjustment and pruning was carried out on April 11; watering was carried out on March 13, April 13, April 23, and May 6. At harvest, tomatoes on 5 plants were randomly picked, the yield was counted, and the yield was estimated. Soil samples were collected and the nematode density in the plot was determined by sucrose centrifugal flotation method and the nitrogen, phosphorus and potassium content of the soil was determined. At the same time, 5 plants were randomly selected and the roots of the plants were completely dug out with a small iron shovel (be careful not to damage the root knots), and the number of root knots was counted.

[0106] 2. Results Analysis

[0107] 2.1 Effects of different treatments on biological control of root-knot nematodes in cherry tomatoes

[0108] The test results of the effects of different treatments on the biological control of cherry tomato root-knot nematodes are shown in Table 1. As can be seen from Table 1, treatment 3 has the least average number of root knots and the highest control effect, which is as high as 92.27% compared with the control treatment 1 and 88.44% compared with treatment 2; treatment 4 is second, and treatment 2 has the lowest control effect.

[0109] Table 1 Effects of different treatments on biocontrol of root-knot nematodes in cherry tomatoes

[0110]

[0111] 2.2 Effects of different treatments on cherry tomato yield

[0112] The first yield estimation was conducted on June 23. The second bunch of fruits from the bottom of the cherry tomato plants were randomly collected. Five bunches of fruits were taken from each plot and weighed. Then the statistics were calculated and the yield was measured. The results of the first yield estimation are shown in Table 2. As can be seen from Table 2, the average per mu yield of treatment 3 was the highest, which was 761.60 kg higher than that of control treatment 1, and the average per mu yield increase rate was as high as 26.56%. The yield differences compared with control treatment 1 and the other treatments were extremely significant (p<0.01).

[0113] On July 11, the second yield estimation was carried out. The second bunch of fruits from the upper part of the cherry tomato plants were randomly collected. Five bunches of fruits were taken from each plot and weighed. Then the statistics were calculated and the yield was measured. The results of the first yield estimation are shown in Table 3. As can be seen from Table 3, the average per mu yield of treatment 3 was the highest, and the average per mu yield increased by 295.68 kg compared with the control treatment 1, and the average per mu yield increase rate was as high as 16.92%. Compared with the control treatments 1 and 2, the yield differences were extremely significant (p<0.01), while the yield difference between treatments 3 and 4 was not significant (p>0.05).

[0114] As shown in Table 4, different treatments had a great impact on the total yield of cherry tomatoes. Treatment 3 had the highest average total yield of cherry tomatoes, with an average yield increase rate of 22.91% per mu, which was significantly different from control treatment 1 and the other treatments (p<0.01).

[0115] Table 2 Effects of different treatments on the first yield estimation results of cherry tomatoes

[0116]

[0117] Table 3 Effects of different treatments on the second yield estimation results of cherry tomatoes

[0118]

[0119] Table 4 Effects of different treatments on total yield of cherry tomatoes

[0120]

[0121] 2.3 Effects of different treatments on chlorophyll content in cherry tomatoes

[0122] During the second yield estimation, 5 leaves were randomly collected from each plot to measure their chlorophyll content. The specific measurement results are shown in Table 5. Although the chlorophyll content of each treatment increased to varying degrees compared with the control treatment 1, there was no significant difference between the treatment groups (p>0.05).

[0123] Table 5 Effects of different treatments on chlorophyll content of cherry tomatoes

[0124]

[0125] 3. Summary

[0126] The test results show that: compared with the blank control and the application of the same amount of fermentation medium per mu, the application of 5L of the anti-nematode liquid fungal agent of the present invention can not only significantly increase the yield of cherry tomatoes (p<0.01), but also significantly improve the prevention effect against root-knot nematode disease, and at the same time can increase the chlorophyll content of cherry tomatoes to a certain extent.

[0127] Experiment 2: Application effect test on melon

[0128] 1. Materials and methods

[0129] 1.1 Test Materials

[0130] The experiment was arranged in a vegetable greenhouse of a professional planting cooperative in Henan on March 3, 2023. The experimental field has convenient transportation, easy observation and management, square plots, flat terrain, uniform fertility, convenient drainage and irrigation, high planting production level, and consistent previous crops. The test soil is loam.

[0131] The tested crop variety was Boyang 61 melon.

[0132] The test fertilizer is the anti-nematode liquid fungal agent of the present invention (effective live bacteria count ≥ 200 million / g), which is provided by the Biological Research Institute Co., Ltd. of Henan Academy of Sciences.

[0133] 1.2 Test methods

[0134] This experiment has 4 treatments, arranged in random blocks, repeated three times, and the area of ​​the plot is 50m 2 .

[0135] Treatment 1: conventional fertilization + drip irrigation of the anti-nematode liquid fungal agent of the present invention at 5 L / mu

[0136] Treatment 2: conventional fertilization + drip irrigation of the fermentation matrix of the anti-nematode liquid fungal agent of the present invention at 5 L / mu

[0137] Treatment 3: conventional fertilization + drip irrigation with an equal amount of clean water 5L / mu

[0138] Treatment 4: Conventional fertilization

[0139] The experiment was divided into plots strictly according to the requirements of the plan. The plots were irrigated in single rows to avoid cross-irrigation and cross-rowing. The plants in the plots were drip-irrigated according to the experimental design. Continuous drip irrigation was used twice before transplanting, with an interval of 7 days each time. At the time of harvest, 5 melons were randomly picked from each plot and weighed, and the yield was counted and estimated. Soil samples were collected, and the nematode density in the plot was determined by sucrose centrifugal flotation method and the nitrogen, phosphorus and potassium content in the soil was determined. At the same time, 5 plants were randomly selected and the roots of the plants were completely dug out with a small iron shovel (be careful not to damage the root knots), and the number of root knots was counted.

[0140] The test greenhouse area is 80m long and 8m wide, with 6 rows in total. The melon seedlings were planted on March 10, 2023, with an average of about 200 melons planted in each row, and an average of 1,250 per mu. The conventional fertilization is 150kg of organic fertilizer per mu; watering for planting on March 10 and watering for seedling return on March 20; harvesting on May 30, 2023.

[0141] 2. Results Analysis

[0142] 2.1 Effects of different treatments on melon yield

[0143] The test results of the effects of different treatments on melon yield are shown in Tables 1 and 2. It can be seen from Tables 1 and 2 that compared with the blank control treatment 4 without sterilization, the average weight of individual melons increased in each treatment, but the difference was not significant (p>0.05); and the average estimated per-acre yield and actual yield of treatment 1 increased significantly compared with other treatments (p<0.01), with treatment 1 having the highest average per-acre yield, and the yield increase rate reaching 38.96%. There was no significant difference in yield between treatments 3 and 4 (p>0.05).

[0144] Table 1 Statistics and analysis of the last estimated yield data at the end of the experiment

[0145]

[0146] Note: Lowercase letters in the table represent significant differences at the 0.05 level, and uppercase letters in the table represent significant differences at the 0.01 level, the same below.

[0147] Table 2 Statistics and analysis of production data at the end of the test

[0148]

[0149]

[0150] 2.2 Effects of different treatments on melon sweetness

[0151] The sweetness of the melons in each treatment was tested on site using a sweetness meter. The results are shown in Table 2. As can be seen from Table 2, although there was no significant difference in the sweetness values ​​among the treatments (p>0.05), their sweetness values ​​increased to varying degrees compared with the blank control treatment 4, among which the sweetness value of treatment 1 increased the most, and the sweetness value of treatment 3 increased the least.

[0152] Table 2 Effects of different treatments on sweetness value of melon

[0153]

[0154] 2.3 Effects of different treatments on the control of melon root-knot nematodes

[0155] The effects of different treatments on the average root knot number and biological control effect of melon roots are shown in Table 3. It can be seen from Table 3 that compared with the blank control treatment 4, treatment 3 and treatment 2, the average root knot number of treatment 1 was significantly reduced (p<0.01), and its control effect was significantly increased (p<0.01), and treatment 1 had the best control effect.

[0156] The effects of different treatments on the number of second-instar larvae of root-knot nematodes in melon soil and the biological control effect are shown in Table 4. It can be seen from Table 4 that compared with the blank control treatment 4, the number of second-instar larvae in treatment 1 was extremely significantly reduced (p<0.01), the control effect was extremely significantly increased (p<0.01), and the control effect was also significantly different from treatments 2 and 3 (p<0.01).

[0157] Table 3 Statistical analysis of the average root knot number and biocontrol effect of different treatments on melon roots

[0158]

[0159] Table 4 Statistical analysis of the number of second-instar larvae and biological control effects of different treatments on root-knot nematodes in melon soil

[0160]

[0161] 3. Summary

[0162] The test results show that applying 5L of the anti-nematode liquid fungal agent of the present invention per mu can not only significantly increase the yield of Boyang 61 melon (p<0.01) compared with the blank control and the application of the same amount of substrate per mu, but also can improve the sweetness value of the melon to a certain extent.

[0163] Experiment 3: Application effect test on lettuce

[0164] 1 Materials and methods

[0165] 1.1 Test materials

[0166] The experiment was arranged in a vegetable greenhouse of a family farm in Henan on October 23, 2023. The test site has convenient transportation, square fields, flat fields, uniform fertility, convenient drainage and irrigation, easy observation and management, and the planting level is equivalent to the local productivity. The test soil is tidal soil. Available nitrogen 46.71mg / kg, available phosphorus 65.74mg / kg, available potassium 150.52mg / kg, soil fertility 519.03mg / kg, soil conductivity 547.0us / cm, pH 6.9.

[0167] Test crops: lettuce, variety: Italian loose leaf lettuce.

[0168] The test fertilizer is the anti-nematode liquid fungal agent of the present invention (effective live bacteria count ≥ 200 million / g), which is provided by the Biological Research Institute Co., Ltd. of Henan Academy of Sciences.

[0169] 1.2 Test methods

[0170] This experiment has 4 treatments, arranged in random blocks, repeated 3 times, and the area of ​​the plot is 100m 2 .

[0171] Treatment 1: conventional fertilization + drip irrigation with 5L of the anti-nematode liquid fungal agent of the present invention per mu

[0172] Treatment 2: conventional fertilization + drip irrigation with 5 L of the anti-nematode liquid fungal agent matrix of the present invention per mu

[0173] Treatment 3: Conventional fertilization + drip irrigation with 5L of water per mu

[0174] The conventional fertilization is 20 kg of nitrogen, phosphorus and potassium compound fertilizer 15-15-15.

[0175] The experiment was divided into plots strictly according to the requirements of the plan, and the plants in the plots were drip irrigated according to the experimental design dosage. After transplanting, continuous drip irrigation was used twice, and 5L of the anti-nematode liquid fungal agent of the present invention was used for drip irrigation per mu each time, with an interval of 7 days each time. The harvest was on December 18, 2023. At the time of harvest, each plot was harvested and yield was calculated and soil samples were collected.

[0176] 2 Results and analysis

[0177] 2.1 Effects of different treatments on lettuce yield

[0178] As can be seen from Table 1, the average yield per mu of lettuce in treatment 1 of the anti-nematode liquid fungal agent of the present invention is the highest, and the difference is extremely significant compared with other groups (p<0.01). Compared with the blank control treatment 3 without bacteria, the average yield per mu of lettuce in treatment 1 increased by 581.34 kg, and the yield increase rate per mu was as high as 20.64%, and the yield difference between the two was extremely significant (p<0.01); compared with the blank control treatment 3, the average yield per mu of lettuce in treatment 2 increased by 86.11 kg, and the yield increase rate per mu reached 3.05%, but the yield difference between the two was not significant (p>0.05).

[0179] Table 1 Effects of different treatments on lettuce yield

[0180]

[0181] Note: Lowercase letters in the table represent 0.05 significance level, and uppercase letters represent 0.01 significance level. Same below.

[0182] 2.2 Effects of different treatments on lettuce root weight and chlorophyll content

[0183] As shown in Table 2, the average root weight of lettuce treated with the anti-nematode liquid fungal agent of the present invention was the largest, and the difference was extremely significant compared with the other groups (p<0.01). Compared with the blank control treatment 3 without bacteria, the average root weight of lettuce in treatment 1 increased by 4.47g / plant, an average increase of 61.57%. As shown in Table 3, the chlorophyll content of lettuce in treatment 1 increased by 5.82μg / g compared with the blank control without bacteria, that is, an average increase of 18.09% compared with the blank control treatment 3 without bacteria. As shown in Tables 2 and 3, the differences in the average root weight and chlorophyll content of treatment 1 compared with the other treatments reached an extremely significant level (p<0.01).

[0184] Table 2 Effects of different treatments on lettuce root weight

[0185]

[0186] Table 3 Effects of different treatments on chlorophyll content of lettuce

[0187]

[0188] 2.3 Effects of different treatments on the physical and chemical properties of lettuce soil

[0189] As can be seen from Table 4, the nitrogen, phosphorus and potassium contents, soil fertility and electrical conductivity of treatment 1 of the anti-nematode liquid fungal agent of the present invention were significantly increased compared with those of the other treatments (p<0.01).

[0190] Table 4 Effects of different treatments on the physical and chemical properties of lettuce in soil

[0191]

[0192] 2.4 Effects of different treatments on the control of root-knot nematodes and their second-instar larvae in soil

[0193] As shown in Table 4, the average root knot number of lettuce in the treatment group 1 of the anti-nematode liquid fungus agent of the present invention was reduced by 2.16 / plant compared with the blank control treatment 3, that is, a reduction of 76.33%. As shown in Table 5, the average number of second-instar larvae in the soil of lettuce in the treatment group 1 of the anti-nematode liquid fungus agent of the present invention was reduced by 520 / g soil compared with the blank control, that is, a reduction of 68.42%. Moreover, the average number of root knots and the average number of second-instar larvae in the soil of the treatment group 1 of the anti-nematode liquid fungus agent of the present invention were significantly different from those of the control treatment 3 and treatment 2 (p<0.01).

[0194] Table 4 Control effect of different treatments on lettuce root-knot nematodes

[0195]

[0196] 3. Summary

[0197] The test results show that: compared with the blank control and the application of the same amount of fermentation matrix per mu, the application of 5L of the anti-nematode liquid fungal agent of the present invention can not only significantly increase the lettuce yield, leaf chlorophyll content and root weight (p<0.01), but also significantly improve the prevention effect against root-knot nematode disease, and at the same time significantly increase the soil nutrient content and fertility (p<0.01).

[0198] While conducting the experiment on Example 1, the same experiments were also conducted on other examples, and the same or similar effects were obtained, which will not be described one by one here.

[0199] Although the present invention only provides the application effect of the new anti-nematode liquid fungal agent on cherry tomatoes, melons and lettuce, it is not limited to these three fruits and vegetables. It can also be applied to vegetables and fruits such as cucumbers, loofahs, cabbages, and field crops such as peanuts, and can achieve significant effects of preventing and controlling root-knot nematodes, promoting growth and increasing production, and improving soil.

[0200] In summary, the microbial agent of the present invention has abundant raw materials, a simple preparation method, and low production cost. It is not only convenient to apply, but also conducive to application in fruit and vegetable planting in facility agriculture, effectively preventing and controlling crop root-knot nematode disease, promoting root development, improving soil structure, and increasing the utilization rate of chemical fertilizers. While increasing yield, it reduces the use of chemical fertilizers, reduces production costs, improves crop quality, and reduces environmental pollution. It has multiple functions such as activating soil, increasing production and efficiency, preventing diseases and resisting drought, and resisting continuous cropping. It has practical promotion and application value, and has huge economic and social benefits.

Claims

1. An anti-nematode liquid fungal agent, which is made of 99.5-99.9% Aspergillus niger J6 liquid agent and 0.1-0.5% functional additives in a volume ratio; the functional additive is a sterilized glycerol, Tween-20 or xanthan gum with a volume concentration of 50%, one, two or three of which are uniformly mixed; The preparation method of the microbial agent is: (1) Strain activation The preserved Aspergillus niger J6 strain was transferred to a slant plate of PDA medium and cultured in a 30° C. incubator for 4 to 5 days until the black spores covered the entire plate, completing the activation of the Aspergillus niger J6 strain; The Aspergillus niger J6 is classified and named as Aspergillus niger, and was deposited in the General Microbiology Center of China Microorganism Culture Collection Committee on October 12, 2010, with the deposit number of CGMCC No. 4220, and the address is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing; The PDA medium is prepared by adding distilled water to 200g of potato, 20g of glucose, 15-20g of agar, and the method is as follows: first weigh 200g of potato, wash and peel, cut into small pieces, add distilled water and boil for 20-30min, filter, heat, add 15-20g of agar, continue heating and stirring to mix, add glucose after the agar is dissolved, stir evenly, add distilled water to 1000mL, sterilize at 115℃ for 20min, and cool to room temperature. (2) Preparation of primary seed solution: Use a pipette to draw 5 mL of PDA liquid medium to wash the black spores on the plate, and use a cell counting plate to determine the spore concentration. 7 CFU / mL, and obtain spore suspension; then take 2 mL of spore suspension and inoculate it into PDA liquid culture medium, and culture it in a shaking incubator at 25-30℃ and 180 r / min for 12-24 h. After the spores germinate, obtain the first-level seed solution; (3) Preparation of fermentation medium: Weigh and prepare liquid culture medium according to the basic salt-glucose culture medium formula, put it into the fermentation tank, sterilize it by high pressure at 115℃~121℃ for 20~30min, and cool it for use; The basic salt culture medium formula is NaCL 1g, KH2PO4 0.5g, K2HPO4 1.5g, (NH4)2SO4 1g, MgSO4•7H2O 0.1g, glucose 2g, fixed volume to 1000 mL, pH 7.0; (4) Preparation of secondary seed solution: Inoculate the first-level seed liquid in a seed fermentation tank filled with the above fermentation medium at an inoculation amount of 5-10% of the volume of the fermentation medium, and culture at 25-30° C. and 30 Hz shaking for 12-48 hours to obtain the second-level seed liquid; (5) Fermentation: The secondary seed liquid is then transferred to another large fermentation tank with a capacity of more than 1000 L for fermentation culture at 25-30°C and 30 Hz shaking for 24-48 h to obtain Aspergillus niger J6 liquid inoculant; (6) Preparation of finished microbial agent: Add 0.1-0.5% functional additives to the Aspergillus niger J6 liquid microbial agent, stir thoroughly, take samples, and conduct tests according to the national standard GB20287-2006. The finished anti-nematode liquid fungal agent is obtained when the number of effective live bacteria reaches more than 500 million / mL, the pH value is 5.0-6.0, and the rate of foreign bacteria is ≤1%.

2. The anti-nematode liquid fungal agent according to claim 1, characterized in that: The microbial agent is prepared by mixing 99.9% of Aspergillus niger J6 liquid microbial agent and 0.1% of 50% sterilized glycerol in a volume ratio, and the preparation method thereof is as follows: (1) Strain activation The preserved Aspergillus niger J6 strain was transferred to a slant plate of PDA medium and cultured in a 30° C. incubator for 4 days until the black spores covered the entire plate, completing the activation of the Aspergillus niger J6 strain; (2) Preparation of primary seed solution Use a pipette to draw 5 mL of PDA liquid medium to wash the black spores on the plate, and use a cell counting plate to determine the spore concentration. 7 CFU / mL, and obtain spore suspension; then take 2 mL of spore suspension and inoculate into PDA liquid culture medium, and culture in a shaking incubator at 30℃ and 180r / min for 12 h. After spore germination, obtain the first-level seed solution; (3) Preparation of fermentation medium: Weigh and prepare liquid culture medium according to the basic salt-glucose culture medium formula, put it into the fermentation tank, sterilize it by high pressure at 115℃ for 20 min, and cool it for use; (4) Preparation of secondary seed solution: The first-level seed solution is inoculated into a seed fermentation tank filled with the above fermentation medium at an inoculation amount of 10% of the volume of the fermentation medium, and cultured at 30°C and 30 Hz shaking for 12 hours to obtain the second-level seed solution; (5) Fermentation: The secondary seed liquid is then transferred to another large fermentation tank with a capacity of more than 1000 L for fermentation culture at 25°C and 30 Hz shaking for 48 h to obtain Aspergillus niger J6 liquid inoculant; (6) Preparation of finished microbial agent: Add 0.1% of 50% sterilized glycerol to the Aspergillus niger J6 liquid microbial agent, stir thoroughly, take samples, and conduct tests according to the national standard GB20287-2006. The finished anti-nematode liquid fungal agent is obtained when the number of effective live bacteria reaches more than 500 million / mL, the pH value is 5.0-6.0, and the rate of foreign bacteria is ≤1%.

3. The anti-nematode liquid fungal agent according to claim 1, characterized in that: The bacterial agent is prepared by mixing 99.9% of Aspergillus niger J6 liquid bacterial agent and 0.1% of Tween-20 in a volume ratio, and the preparation method thereof is as follows: (1) Strain activation The preserved Aspergillus niger J6 strain was transferred to a slant plate of PDA medium and cultured in a 30° C. incubator for 4 days until the black spores covered the entire plate, completing the activation of the Aspergillus niger J6 strain; (2) Preparation of primary seed solution Use a pipette to draw 5 mL of PDA liquid medium to wash the black spores on the plate, and use a cell counting plate to determine the spore concentration. 7 CFU / mL, and obtain spore suspension; then take 2 mL of spore suspension and inoculate into PDA liquid culture medium, and culture in a shaking incubator at 25℃ and 180r / min for 24 h. After spore germination, obtain the first-level seed solution; (3) Preparation of fermentation medium: Weigh and prepare liquid culture medium according to the basic salt-glucose culture medium formula, put it into the fermentation tank, sterilize it by high pressure at 115℃ for 30 min, and cool it for use; (4) Preparation of secondary seed solution: The first-level seed solution was inoculated into a seed fermentation tank filled with the above fermentation medium at an inoculation rate of 5% of the volume of the fermentation medium, and cultured at 30°C and 30 Hz with shaking for 12 hours to obtain the second-level seed solution; (5) Fermentation: The secondary seed liquid is then transferred to another large fermentation tank with a capacity of more than 1000 L for fermentation culture at 25°C and 30 Hz shaking for 48 h to obtain Aspergillus niger J6 liquid inoculant; (6) Preparation of finished microbial agent: Add 0.1% sterilized Tween-20 to the Aspergillus niger J6 liquid microbial agent, stir thoroughly, take samples, and conduct tests according to the national standard GB20287-2006. The finished anti-nematode liquid fungal agent is obtained when the effective live bacteria count reaches more than 500 million / mL, the pH value is 5.0-6.0, and the contaminant bacteria rate is ≤1%.

4. The anti-nematode liquid fungal agent according to claim 1, characterized in that: The bacterial agent is prepared by mixing 99.9% of Aspergillus niger J6 liquid bacterial agent and 0.1% of xanthan gum in a volume ratio, and the preparation method thereof is as follows: (1) Strain activation The preserved Aspergillus niger J6 strain was transferred to a slant plate of PDA medium and cultured in a 30° C. incubator for 5 days until the black spores covered the entire plate, completing the activation of the Aspergillus niger J6 strain; (2) Preparation of primary seed solution Use a pipette to draw 5 mL of PDA liquid medium to wash the black spores on the plate, and use a cell counting plate to determine the spore concentration. 7 CFU / mL, and obtain spore suspension; then take 2 mL of spore suspension and inoculate into PDA liquid culture medium, and culture in a shaking incubator at 30℃ and 180r / min for 16h, and after spore germination, obtain the primary seed solution; (3) Preparation of fermentation medium: Weigh and prepare liquid culture medium according to the basic salt-glucose culture medium formula, put it into the fermentation tank, sterilize it by high pressure at 121℃ for 20 min, and cool it for use; (4) Preparation of secondary seed solution: The first-level seed solution is inoculated into a seed fermentation tank filled with the above fermentation medium at an inoculation rate of 8% of the volume of the fermentation medium, and cultured at 28° C. and 30 Hz shaking for 48 hours to obtain the second-level seed solution; (5) Fermentation: The secondary seed liquid is then transferred to another large fermentation tank with a capacity of more than 1000 L for fermentation culture at 28°C and 30 Hz shaking for 36 h to obtain Aspergillus niger J6 liquid inoculant; (6) Preparation of finished microbial agent: Add 0.1% xanthan gum to the Aspergillus niger J6 liquid microbial agent, stir thoroughly, take samples, and test according to the national standard GB20287-2006. The effective live bacteria count reaches more than 500 million / mL, the pH value is 5.0-6.0, and the foreign bacteria rate is ≤1%. This is the finished anti-nematode liquid fungal agent.

5. The anti-nematode liquid fungal agent according to claim 1, characterized in that: The bacterial agent is prepared by uniformly mixing 99.5% of Aspergillus niger J6 liquid bacterial agent and 0.5% of a mixed solution of 50% glycerol, Tween-20 and xanthan gum in a volume ratio, and the preparation method thereof is as follows: (1) Strain activation The preserved Aspergillus niger J6 strain was transferred to a slant plate of PDA medium and cultured in a 30° C. incubator for 4 days until the black spores covered the entire plate, completing the activation of the Aspergillus niger J6 strain; (2) Preparation of primary seed solution Use a pipette to draw 5 mL of PDA liquid medium to wash the black spores on the plate, and use a cell counting plate to determine the spore concentration. 7 CFU / mL, and obtain spore suspension; then take 2 mL of spore suspension and inoculate into PDA liquid culture medium, and culture in a shaking incubator at 28℃ and 180r / min for 24 h. After the spores germinate, obtain the first-level seed solution; (3) Preparation of fermentation medium Weigh and prepare liquid culture medium according to the basic salt-glucose culture medium formula, put it into the fermentation tank, sterilize it at 121℃ for 20min, and cool it for use; (4) Preparation of secondary seed solution: Inoculate the first-level seed liquid in a seed fermentation tank filled with the above fermentation medium at an inoculation rate of 5-10% of the volume of the fermentation medium, and culture at 25°C and 30HZ shaking for 24 hours to obtain the second-level seed liquid; (5) Fermentation: The secondary seed liquid is then transferred to another large fermentation tank with a capacity of more than 1000 L for fermentation culture at 30°C and 30 Hz shaking for 24 h to obtain Aspergillus niger J6 liquid inoculant; (6) Preparation of finished microbial agent: Add 0.5% of a mixture of 50% glycerol, Tween-20 and xanthan gum to the Aspergillus niger J6 liquid microbial agent, stir thoroughly, take samples, and conduct tests according to the national standard GB20287-2006. The finished anti-nematode liquid fungal agent is obtained when the number of effective live bacteria reaches more than 500 million / mL, the pH value is 5.0-6.0, and the rate of foreign bacteria is ≤1%.

6. The anti-nematode liquid fungal agent according to claim 1, characterized in that: The bacterial agent is prepared by uniformly mixing 99.7% of Aspergillus niger J6 liquid bacterial agent and 0.3% of a mixed solution of 50% glycerol and Tween-20 in a volume ratio, and the preparation method thereof is as follows: (1) Strain activation The preserved Aspergillus niger J6 strain was transferred to a slant plate of PDA medium and cultured in a 30° C. incubator for 4.5 days until the black spores covered the entire plate, thus completing the activation of the Aspergillus niger J6 strain; (2) Preparation of primary seed solution Use a pipette to draw 5 mL of PDA liquid medium to wash the black spores on the plate, and use a cell counting plate to determine the spore concentration. 7 CFU / mL, and obtain spore suspension; then take 2 mL of spore suspension and inoculate into PDA liquid culture medium, and culture it in a shaking incubator at 28℃ and 180r / min for 20 h. After the spores germinate, obtain the first-level seed liquid; (3) Preparation of fermentation medium Weigh and prepare liquid culture medium according to the basic salt-glucose culture medium formula, put it into the fermentation tank, sterilize it at 121℃ for 20min, and cool it for use; (4) Preparation of secondary seed solution: Inoculate the first-level seed liquid in a seed fermentation tank filled with the above fermentation medium at an inoculation rate of 5-10% of the volume of the fermentation medium, and culture at 28°C and 30HZ shaking for 20 hours to obtain the second-level seed liquid; (5) Fermentation: The secondary seed liquid is then transferred to another large fermentation tank with a capacity of more than 1000 L for fermentation culture at 30°C and 30 Hz shaking for 36 h to obtain Aspergillus niger J6 liquid inoculant; (6) Preparation of finished microbial agent: Add 0.3% of a mixture of 50% sterilized glycerol and Tween-20 to the Aspergillus niger J6 liquid microbial agent, stir thoroughly, take samples, and conduct tests according to the national standard GB20287-2006. If the number of effective live bacteria reaches more than 500 million / mL, the pH value is 5.0-6.0, and the rate of foreign bacteria is ≤1%, it is the finished anti-nematode liquid fungal agent.

7. Use of the anti-nematode liquid fungal agent according to any one of claims 1 to 6 in preventing and controlling nematode diseases in fruits and vegetables, with a dosage of 5 L / mu.

8. The use of the anti-nematode liquid fungal agent according to claim 7 in preventing and controlling nematode diseases in fruits and vegetables, characterized in that: The fruits and vegetables are melon, cherry tomato and lettuce.

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