Beauveria bassiana Bb20240406 and its application in pest and disease control

Abstract

The present invention relates to the field of microbial technology, and discloses a Beauveria bassiana ( Beauveria bassiana ) strain Bb20240406 and its application in pest control. Its preservation number is: CGMCC No. 41802. This strain has high insecticidal activity against above-ground and underground pests of peanuts and good control effects; it has strong inhibitory effects on the pathogens of peanut fruit rot, root rot, southern blight, and leaf diseases, and good field control effects. In addition, the impact of this strain on the population of Orius sauteri is lower than that of conventional chemical pesticides. Applying the strain provided by the present invention to production can reduce the dosage and application frequency of chemical pesticides, solve the problems of pesticide residues in agricultural products and environmental pollution; reduce the impact on the population of natural enemies, protect the farmland ecological environment, and maintain ecological balance.

Description

Technical Field

[0001] The present invention relates to the technical field of microorganisms, and in particular to Beauveria bassiana Bb20240406 and application thereof in disease and insect pest control. Background Art

[0002] Beauveria belongs to the genus Beauveria ( Beauveria ), is an entomogenous fungus. At present, the academic community generally believes that there are 6 branches of Beauveria bassiana, among which Beauveria bassiana is considered to be one of the insect pathogenic fungi with great development potential. Although it has a long development history, it is mainly used for biological control of pests and has a wide range of applications, while research on plant disease control is relatively small. In recent years, environmental awareness in agricultural production has been continuously improved, and there have been many reports on the success of Beauveria bassiana in biological control of plant diseases. Studies have shown that onion bulbs treated with Beauveria bassiana are not easily affected by Fusarium oxysporum onion-specific type ( F. Oxysporum f. sp. cepae ) infection, which can effectively protect crops. A study used a solution prepared by mixing Beauveria bassiana with methylcellulose to coat tomato seeds and found that tomato seedlings protected by Beauveria bassiana can effectively resist Rhizoctonia solani ( Rhizoctonia solani ) and Pythium spp. Other studies have explored the mechanisms by which Beauveria bassiana inhibits soil-borne pathogens, demonstrating that it primarily antagonizes pathogens through competition and resistance. Other studies have found that Beauveria bassiana inhibits the mycelial growth of Sclerotinia sclerotiorum, Fusarium wilt, and Gibberella fusca, with inhibition rates exceeding 50% on the third day.

[0003] Peanuts are an important oilseed crop in my country. In recent years, the economic benefits of peanut cultivation have become apparent, leading to a gradual expansion in cultivated areas and a significant increase in continuous cropping. This, coupled with complex and variable climatic conditions, has led to an increasing incidence of peanut pests and diseases, severely impacting both yield and quality. Common pests such as western flower thrips, peanut aphids, white grubs, and beet armyworms, as well as diseases such as leaf spot, root rot, fruit rot, and white rot, have caused significant losses to peanut production.

[0004] Currently, chemical pesticides are the primary means of controlling peanut pests and diseases. However, long-term use leads to increased resistance in pests and diseases, resulting in pesticide residues in agricultural products, environmental pollution, and disruption of farmland ecological balance. Therefore, the development of safe, efficient, and environmentally friendly biological control methods is urgent. Providing highly effective Beauveria bassiana strains for superior peanut germplasm and their application are urgent challenges facing those skilled in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a kind of Beauveria bassiana ( Beauveria bassiana), and its application in the prevention and control of peanut diseases and pests is provided. After further identification, this strain has high insecticidal activity against above-ground and underground pests of peanuts and good control effects; it has strong inhibitory effects on the pathogens of peanut fruit rot, root rot, southern blight, and leaf diseases, and good field control effects. In addition, the impact of this strain on the population of Orius sauteri is lower than that of conventional chemical pesticides. Applying this strain in production can reduce the dosage and frequency of chemical pesticides, solve the problems of pesticide residues in agricultural products and environmental pollution; reduce the impact on the population of natural enemies, protect the farmland ecological environment, and maintain ecological balance.

[0006] To achieve the above object, the technical solutions provided by the present invention are as follows:

[0007] In the first aspect of the present invention, a Beauveria bassiana Bb20240406 strain is provided, and the preservation number of this strain is CGMCC No. 41802, the preservation date is January 21, 2025, and the preservation taxonomic name is Beauveria bassiana Beauveria bassiana , the preservation unit is the General Microbiology Center of the China Committee for Culture Collection of Microorganisms, the address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Postcode: 100101, Tel: 8610 - 64807355.

[0008] In the second aspect of the present invention, a fermentation broth, a bacterial suspension, or a sterile supernatant thereof or a preparation containing the above-mentioned Beauveria bassiana Bb20240406 strain is provided.

[0009] In the third aspect of the present invention, the above-mentioned Beauveria bassiana Bb20240406 strain or the above-mentioned fermentation broth, bacterial suspension, or a sterile supernatant thereof or a preparation is applied in the prevention and control of Frankliniella occidentalis, Aphis craccivora, Holotrichia parallela larvae, Spodoptera exigua, and Bemisia tabaci.

[0010] In the fourth aspect of the present invention, the above-mentioned Beauveria bassiana Bb20240406 strain or the above-mentioned fermentation broth, bacterial suspension, or a sterile supernatant thereof or a preparation is applied in the prevention and control of peanut fruit rot, peanut root rot, peanut southern blight, peanut brown spot, and peanut black spot.

[0011] In the fifth aspect of the present invention, the above-mentioned Beauveria bassiana Bb20240406 strain or the above-mentioned fermentation broth, bacterial suspension, or a sterile supernatant thereof or a preparation is applied in the inhibition of peanut pathogens, and the peanut pathogens are: Fusarium solani ( Fusarium solani ), Neocosmospora vasinfecta ( Neonectria invadens ), Sclerotium rolfsii ( Sclerotium rolfsii )

[0012] The sixth aspect of the present invention provides the application of the above-mentioned Beauveria bassiana Bb20240406 strain, or the above-mentioned fermentation broth, bacterial suspension, sterile supernatant thereof or its preparation in promoting peanut fruit retention and yield increase.

[0013] The seventh aspect of the present invention provides a bacterial agent for promoting peanut fruit retention and yield increase, and the active ingredient of the bacterial agent includes the above-mentioned Beauveria bassiana Bb20240406 strain.

[0014] The eighth aspect of the present invention provides the application of the above-mentioned Beauveria bassiana Bb20240406 strain, or the above-mentioned bacterial agent for promoting peanut fruit retention and yield increase in the production of biological organic fertilizer.

[0015] The ninth aspect of the present invention provides a biological organic fertilizer, which contains the above-mentioned Beauveria bassiana Bb20240406 strain or the above-mentioned bacterial agent for promoting peanut fruit retention and yield increase.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] (1) Significantly effective in pest and disease control

[0018] (1) Pest control

[0019] Efficient control of multiple pests: The Beauveria bassiana Bb20240406 strain shows excellent virulence against the main pests such as Frankliniella occidentalis, Aphis craccivora, Holotrichia oblita, and Spodoptera exigua commonly found in peanut fields. Through virulence determination, the median lethal time LT50 of this strain against Frankliniella occidentalis, Aphis craccivora, Holotrichia oblita, and Spodoptera exigua are 2.71 d, 2.83 d, 2.77 d, and 3.06 d respectively, indicating that it can cause a large number of pests to die in a short time, effectively reduce the pest population, and reduce the damage of pests to peanut plants.

[0020] Strong ability to continuously control pests: In the field control experiment, whether it is underground pests such as Holotrichia oblita or above-ground pests, the Bb20240406 strain shows good continuous pest control effect. Taking the control of above-ground pests in spring peanut fields as an example, although the early control effect after the first application of the drug is lower than that of chemical pesticides, the control effect shows an upward trend after 7 days and is significantly higher than that of chemical pesticides after 15 days, indicating that this strain has strong adaptability and the ability to continuously play a role in the field environment.

[0021] Wide applicability to different plots and sowing periods: The control test results in peanut fields with different plots and sowing periods in Baoding City show that the strain Bb20240406 can effectively control pests under various planting conditions. For example, in different environments such as net rooms with high pest densities, spring peanut fields with serious occurrence of white grubs all year round, spring peanut fields in practice gardens, and wheat stubble peanut fields, by adjusting the application rate, this strain can achieve good control effects, significantly reducing the damage rate of peanut pods and providing reliable guarantee for the safe production of peanuts.

[0022] (2)Disease control

[0023] Obvious inhibitory effect on pathogenic bacteria: The plate confrontation test shows that the inhibitory rate of Beauveria bassiana Bb20240406 on the pathogenic bacteria of peanut fruit rot and root rot is significantly higher than that of other strains. This means that this strain can effectively inhibit the growth and reproduction of pathogenic bacteria, reducing the occurrence and spread of diseases.

[0024] Good control effects on various diseases: In field and pot control tests, the strain Bb20240406 has significant control effects on peanut fruit rot, root rot, leaf diseases (such as brown spot and black spot), etc. When controlling fruit rot in peanut fields in Luan County, Tangshan, with an application rate of 67.5 trillion spores / hm², the control effect is significant; in the pot test for controlling root rot, with a spore content of 6 trillion spores / hm², the control effect is significant; when spraying to control peanut brown spot and black spot, with an application rate of 135 trillion spores / hm², the control effect is significantly higher than that of common chemical pesticides. By effectively controlling diseases, the healthy growth of peanut plants is guaranteed, and the yield and quality of peanuts are improved.

[0025] (II)Outstanding environmental protection advantages

[0026] Reduce the use of chemical pesticides: The strain Beauveria bassiana Bb20240406 provided by this invention can be an effective substitute for chemical pesticides and play an important role in the control of peanut pests and diseases. Using this strain can reduce the dosage and application frequency of chemical pesticides, reducing the environmental pollution risk caused by the large use of chemical pesticides. For example, in the control test of above-ground pests in peanut fields, the control effect of the strain Bb20240406 in the later stage is better than that of chemical pesticides, indicating that to a certain extent, the dependence on chemical pesticides can be reduced, thus reducing the residues of chemical pesticides in soil, water bodies and the air.

[0027] Reduce pesticide residues in agricultural products: With the reduction of the use amount of chemical pesticides, the pesticide residues in agricultural products are correspondingly reduced. This not only helps to ensure the food safety of consumers, but also improves the market competitiveness of peanuts and their processed products, meeting the requirements of green agriculture and sustainable development.

[0028] Protect the farmland ecological environment: Beauveria bassiana Bb20240406 is a biological agent with less damage to the farmland ecological environment. Compared with chemical pesticides, it will not cause serious negative impacts on soil microbial communities, water ecosystems, etc., which is conducive to maintaining the balance and stability of the farmland ecosystem.

[0029] (III) Friendly to natural enemies

[0030] Reduce the killing of Orius sauteri: Orius sauteri is an important natural enemy insect in peanut fields and plays a key role in controlling the population of pests. Comparative studies have shown that the impact of Beauveria bassiana Bb20240406 on the number of Orius sauteri is significantly lower than that of chemical pesticides such as 25% imidacloprid wettable powder, 25% thiamethoxam water dispersible granules, and 60g / L spinetoram suspension concentrate. At different time points after spraying, the decline in the number of Orius sauteri in the Bb20240406 treatment area was not significant, and 15 days after spraying, the number of Orius sauteri in this treatment area was significantly higher than that in the chemical pesticide treatment area, and the insect population recovered significantly. This shows that this strain can protect the population of natural enemy insects such as Orius sauteri to the greatest extent while controlling pests and diseases.

[0031] Enhance the natural pest control ability: Due to the protective effect of Beauveria bassiana Bb20240406 on natural enemy insects, it helps to maintain the biodiversity of the farmland ecosystem and enhance the pest control ability of natural enemies. Natural enemy insects can continuously prey on and parasitize pests, forming a long-term and stable ecological prevention and control mechanism, further reducing the damage of pests to peanuts and lowering the cost of pest and disease control.

[0032] (IV) Significant yield increase effect

[0033] Improve the quality and yield of peanut pods: By effectively controlling peanut pests and diseases, the Beauveria bassiana Bb20240406 strain creates a good growth environment for peanut plants, reduces phenomena such as flower and fruit dropping and pod rot caused by pests and diseases, and improves the plumpness and quality of peanut pods. In peanut field trials in different plots and sowing periods, the treatment areas using this strain all showed obvious yield increase effects. For example, in the control trials of spring peanut fields and wheat stubble peanut fields, the peanut yields in the Bb20240406 treatment areas were significantly higher than those in the control areas, increasing the economic income of farmers.

[0034] Ensure the sustainable development of the peanut industry: Stable yields and good quality are the basis for the sustainable development of the peanut industry. The application of the Beauveria bassiana Bb20240406 strain not only increases peanut yields, but also reduces production costs and environmental risks, which is conducive to ensuring the healthy and stable development of the peanut industry and is of great significance for promoting agricultural efficiency increase and farmers' income increase. Description of the drawings

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to the provided drawings.

[0036] Figure 1 It is the dynamic growth and decline curve of Orius sauteri after pesticide application;

[0037] Figure 2 It is the confrontation culture colony of Fusarium solani and Beauveria bassiana Bb20240406;

[0038] Figure 3 It is the confrontation culture colony of Neocosmospora vasinfecta and Beauveria bassiana Bb20240406;

[0039] Figure 4 It is the confrontation culture colony of Fusarium oxysporum and Beauveria bassiana Bb20240406;

[0040] Figure 5 It is the confrontation culture of 5 biocontrol bacteria and Sclerotium rolfsii: Figure 5 In which a represents the confrontation culture colony of Trichoderma harzianum and Sclerotium rolfsii; Figure 5 In which b represents the confrontation culture colony of Bacillus megaterium and Sclerotium rolfsii; Figure 5 In which c represents the confrontation culture colony of Bacillus subtilis and Sclerotium rolfsii; Figure 5 In which d represents the confrontation culture colony of Beauveria bassiana Bb20240406 and Sclerotium rolfsii; Figure 5 In which e represents the confrontation culture colony of Metarhizium anisopliae M18-8-4 and Sclerotium rolfsii; Figure 5 In which f represents the single culture colony of Sclerotium rolfsii. Detailed implementation manners

[0041] The following further illustrates the present invention in conjunction with embodiments.

[0042] A strain was isolated in the present invention. Through comprehensive analysis of data such as colony and cell morphology, physiological and biochemical characteristics, and 16S rRNA gene sequence determination, this strain was identified as Beauveria bassiana ( Beauveria bassiana ) and named Bb20240406. This strain was deposited in the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on January 21, 2025, with the deposit number: CGMCC No. 41802.

[0043] This strain has high insecticidal activity against above-ground and underground pests of peanuts and good control effects; it has strong inhibitory effects on the pathogens of peanut fruit rot, root rot, southern blight, and leaf diseases, and good field control effects. In addition, the impact of this strain on the population of Orius sauteri is lower than that of conventional chemical pesticides.

[0044] The following are specific examples of the present invention:

[0045] Example 1: Isolation and identification of Beauveria bassiana ( Beauveria bassiana ) Bb20240406

[0046] I. Isolation of Beauveria bassiana

[0047] The corn borer larvae infected with Beauveria bassiana were surface-sterilized with 75% alcohol in a laminar flow hood for 3 - 5 min. Then transferred to 0.5% sodium hypochlorite solution (NaClO) and soaked for 2 min, followed by rinsing 3 times with sterile water. The water from the third rinse was inoculated back onto a PDA plate to verify the disinfection effect. The insect bodies were placed on sterile filter paper to absorb moisture, and then cut into small pieces with a scalpel and placed on a PDA medium plate (containing 0.05% chloramphenicol). 3 pieces of cadaver were inoculated into each petri dish and arranged in a triangle. Incubated in an incubator at 26°C for 10 d until the insect bodies were covered with white mycelia. The white and pure mycelia at the edge were picked with an inoculation loop and streaked for purification. After single colonies grew, they were transferred to a new PDA medium, and this was repeated 3 times to obtain a purified single strain, which was stored in a 4°C refrigerator.

[0048] II. Identification and classification at the molecular level based on ITS sequence characteristics

[0049] DNA was extracted from the mycelia of strain Bb20240406. Then, using the extracted genomic DNA of Bb20240406 as a template and the universal primers ITS-1 and ITS-2 for the fungal ITS region as primers, PCR amplification was carried out to obtain an amplification product, namely the ITS sequence of Bb2L0240406. The primer sequences are as follows: ITS-1: 5′-TCCGTAGGTGAACCTGCGG-3′; ITS-2: 5′-TCCTCCGCTTATTGATATGC-3′. The reaction conditions for PCR were: 95°C for 5 min, 94°C for 30 s, 57°C for 30 s, 72°C for 90 s, and 72°C for 10 min. 3 μL of the PCR product was detected by 1.2% agarose gel electrophoresis. Then it was sent for sequencing.

[0050] The ITS sequence of Bb20240406 (see SEQ ID No. 1) was sequenced and the ITS sequence of Bb20240406 was subjected to a homology BLAST comparison in the Genbank database. The results showed that the ITS sequence of the strain Bb20240406 of the present invention and the ITS sequence of Beauveria bassiana were more than 99% homologous. At the same time, a phylogenetic tree was constructed using MEGA software. The results showed that the strain Bb20240406 of the present invention was clustered with Beauveria bassiana, indicating that Bb20240406 belongs to the genus Beauveria bassiana in terms of classification.

[0051] Example 2: Beauveria bassiana ( Beauveria bassiana ) Biological characteristics of Bb20240406

[0052] 1. Study on the control effect of Beauveria bassiana Bb20240406 strain on spring peanut field white grubs

[0053] Using Beauveria bassiana strain Bb20240406 as the inoculum, a solid fermentation medium was obtained via a liquid-solid biphasic fermentation method, and the conidia content was determined. Before sowing, the solid fermentation medium was weighed according to the conidia dosage of the experimental treatment, diluted with wheat bran, and evenly spread into the peanut sowing furrow. An equal amount of wheat bran was used as a control. Field plots were 30 m² in size, with each treatment arranged in randomized blocks and replicated three times. One day before peanut harvest, a five-point sampling method was conducted, covering an area of 1 m². Peanut pod damage was assessed using a specific grading scale (Grade 0: pod intact, no signs of damage; Grade 1: pod skin damaged, kernel intact; Grade 2: less than half of the kernel damaged; Grade 3: more than half of the kernel damaged). Pod damage index, yield, and control efficacy were calculated.

[0054] The experiment was conducted from May to September 2019 in Xiwuyao Village, Wuyao Township, Lianchi District, Baoding City, Hebei Province. The peanut variety used was Jihua No. 6. The farmland had a monoculture of crops, primarily wheat and corn. Peanuts had been planted year after year in the experimental site, resulting in a high incidence of white grubs year-round. The treatment methods and pesticide dosages are shown in Table 1.

[0055] Table 1 - Dosage and application method for spring peanut field control of white grubs

[0056]

[0057] The results of the control of white grubs in spring peanut fields are shown in Table 2. 2 The control effect of (II-2) was 84.88%, and the fruit preservation effect was 80.34%, which were significantly higher than those of other treatments. Its yield was 4209.33 kg / hm 2, there was no significant difference in yield compared with that of the treatment with 30% phoxim microcapsule suspension (II-6) at 4026.00 kg / hm 2 There was no significant difference in the control effect of Beauveria bassiana Bb20240406 applied at 300 trillion spores / hm 2 (II-1) and the wettable powder of Beauveria bassiana at 450 trillion spores / hm 2 (II-4), and the yields were 4114.00 kg / hm 2 and 3549.33 kg / hm 2 respectively. The control effect of the wettable powder of Beauveria bassiana at 300 trillion spores / hm 2 (II-3) was 57.12%, which was significantly lower than that of other treatments. During the field investigation of the insect population (Table 3), it was found that the control effect of treatment II-2 was 50.00%, which was significantly higher than that of other treatments, and the control effect of treatment II-3 was significantly lower than that of other treatments.

[0058] Table 2 - Control results of Beauveria bassiana Bb20240406 on grubs in spring peanut fields of farmland

[0059]

[0060] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level tested by Duncan's multiple comparison method.

[0061] Table 3 - Effects of Beauveria bassiana Bb20240406 on the grub population in spring peanut fields of farmland

[0062]

[0063] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level tested by Duncan's multiple comparison method.

[0064] II. Study on the control effect of highly virulent strains on above-ground pests in peanut fields

[0065] The experiment was conducted from June 2019 to August 2019 in Xiwuyao Village, Wuyao Township, Lianchi District, Baoding City, Hebei Province. The peanut variety was Jihua 16. The experimental treatment methods and chemical agent dosages are shown in Table 4. Before the experiment, the solid fermentation material of highly virulent strains was obtained through liquid-solid biphasic fermentation, and the content of conidia was measured. During the experiment, the solid fermentation material was weighed according to the application rate and made into a suspension with sterile water containing 0.05% Tween-80, and the water with 0.05% Tween-80 was used as the clear water control. The plot area was 30 m2, and the experiment was arranged in a randomized block design with 3 replicates for each treatment. A sprayer (CD-16B) was used to spray it wet on the peanut leaves. Before applying the medicine, the types of pests, the pest population density, and the damage situation of peanut leaves were investigated. Five points were selected in each plot, and five hills of peanuts were selected at each point to investigate the numbers of Frankliniella occidentalis, aphids, and Bemisia tabaci on the top 5 newly compound leaves, and at the same time, the numbers of damaged leaves and the damage grades were investigated. The grading standard for peanut leaf damage is shown in Table 10.

[0066] Table 4 - Dosages of Chemical Agents for Field Control Effect Tests of Above-ground Pests in Peanut Fields

[0067]

[0068] Peanut yield measurement method: The yield was investigated 1 day before peanut harvest. Five points were randomly selected in each plot, and 1 m 2 was taken at each point, and the pod weights of each sampling point were weighed separately.

[0069] (1) Research on the Control Effect of Highly Virulent Strains on Above-ground Pests in Spring Peanut Fields in the First Application of Medicine

[0070] The experiment was sprayed for the first time according to the treatment methods and chemical agent dosages in Table 4. The pest population density was investigated before applying the medicine, and the control effects were investigated on the 3rd, 7th, 10th, and 15th days after applying the medicine.

[0071] Table 5 shows the efficacy of different treatments against western flower thrips in peanuts. Before application, there were no significant differences among the treatments. Three days after application, the control efficacy of 60 g / L spinetoram suspension concentrate (I-1) was 79.05%, significantly higher than that of the other treatments. The control efficacy of 25% thiamethoxam water dispersible concentrate (I-3) and 25% imidacloprid wettable powder (I-4) was 66.99% and 64.88%, respectively, significantly higher than that of Beauveria bassiana Bb20240406, applied at 45 trillion spores / hm² (I-2). Seven days after application, the control efficacy of Bb20240406 showed an increasing trend, with no significant differences among the four treatments. Ten days after application, the control efficacy of Bb20240406 increased, significantly exceeding that of the other treatments, reaching 79.30%. 15 days after application, the control effect of Beauveria bassiana Bb20240406 increased to 86.52%, which was significantly higher than that of other treatments; the control effects of spinetoram and thiamethoxam decreased to 64.04% and 62.75% respectively, with no significant difference between the two, and were significantly higher than imidacloprid, which had a control effect of 54.03%, a significant decrease.

[0072] Table 5 - Control results of western flower thrips in spring peanut fields in the first application of each treatment

[0073]

[0074] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level in Duncan's multiple comparison test.

[0075] Table 6 shows the control results of different treatments against peanut aphids. Before application, there were no significant differences among the treatments. Three days after application, the control efficacy of 25% thiamethoxam water dispersible concentrate (I-3) and 25% imidacloprid wettable powder (I-4) was 83.43% and 84.94%, respectively, significantly higher than that of 60 g / L spinetoram suspension concentrate (I-1) and 45 trillion spores / hm2. 2 The control efficacy of Beauveria bassiana Bb20240406 (I-2). Seven days after application, the control efficacy of Bb20240406 rose to 68.93%, significantly higher than that of the other treatments. Ten days after application, the control efficacy of Bb20240406 reached 87.14%, significantly higher than that of the other treatments. Fifteen days after application, the control efficacy of Bb20240406 decreased slightly to 76.94%, still significantly higher than that of the other treatments. The control efficacy was in the order of thiamethoxam > imidacloprid > spinetoram.

[0076] Table 6 - Control results of aphids in spring peanut fields after the first application of each treatment

[0077]

[0078] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0079] The protection results of strain Bb20240406 on peanut leaves are shown in Table 7. In Table 7, treatments 1 to 5 are 60 g / L spinetoram suspension concentrate, Beauveria bassiana Bb20240406 at 45 trillion spores / hm 2 The corrected leaf protection effect was 47.16%, showing no significant difference from 25% thiamethoxam water dispersible granule and 25% imidacloprid wettable powder. The corrected leaf protection effect of 60 g / L spinetoram suspension concentrate was the lowest, at 34.09%. At 10 days after spraying, there was no significant difference in the corrected leaf protection effects of Beauveria bassiana Bb20240406, spinetoram, and imidacloprid, which were 56.02%, 48.17%, and 49.22% respectively, significantly higher than that of thiamethoxam. At 15 days after spraying, the corrected leaf protection effect of Beauveria bassiana Bb20240406 was significantly higher than that of other treatments, at 65.88%. Followed by spinetoram, at 55.62%.

[0080] Table 7 - Leaf protection effects of the first pesticide application for each treatment on spring peanut fields

[0081]

[0082] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0083] (2) Study on the control effect of highly virulent strains by the second pesticide application against aboveground pests in spring peanut fields

[0084] The experiment was sprayed for the second time according to the treatment method and dosage of pesticides in Table 4. The experimental field was sprayed for the second time 7 days after the end of the first pesticide application survey. The insect population base was investigated before spraying, and the control effects after spraying were investigated on the 3rd, 7th, 10th, and 15th days after spraying.

[0085] The control effects of each treatment on Frankliniella occidentalis in peanuts after the second pesticide application are shown in Table 8. Before pesticide application, there were no significant differences among the treatments. Three days after pesticide application, the control effect of the 60 g / L spinetoram suspension concentrate (II-1) was 81.43%, which was significantly higher than that of other treatments. The control effects of the 25% thiamethoxam water dispersible granule (II-3) and the 25% imidacloprid wettable powder (II-4) were 68.05% and 69.50%, respectively, which were significantly higher than that of Beauveria bassiana Bb20240406 applied at 45 trillion spores / hm 2 (II-2). Seven days after pesticide application, there was no significant difference in the control effects between Beauveria bassiana Bb20240406 and spinetoram, which were 69.66% and 66.61% respectively. There was no significant difference in the control effects between thiamethoxam and imidacloprid. Ten days after pesticide application, the control effect of Beauveria bassiana B16-5 increased and was significantly higher than that of other treatments, with a control effect of 71.44%. Fifteen days after pesticide application, the control effect of the Beauveria bassiana B16-5 treatment increased to 74.46%, which was significantly higher than that of other treatments; there was no significant difference in the control effects of spinetoram, thiamethoxam and imidacloprid.

[0086] Table 8 - Control results of the second pesticide application of each treatment on Frankliniella occidentalis in spring peanut fields

[0087]

[0088] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level tested by the Duncan's multiple comparison method.

[0089] The control effects of each treatment on peanut aphids after the second pesticide application are shown in Table 9. Before pesticide application, there were no significant differences among the treatments. Three days after pesticide application, the control effects of the 25% thiamethoxam water dispersible granule (II-3) and the 25% imidacloprid wettable powder (II-4) were 72.44% and 73.68%, respectively. There was no significant difference between the two, but they were significantly higher than the 60 g / L spinetoram suspension concentrate (II-1) and Beauveria bassiana Bb20240406 applied at 45 trillion spores / hm 2 (II-2). Seven days after pesticide application, the control effect of Beauveria bassiana Bb20240406 increased and was significantly higher than that of other pesticide treatments, at 70.73%. There was no significant difference among the other groups of treatments. Ten days after pesticide application, the control effect of Bb20240406 was 82.01%, which was significantly higher than that of other groups of treatments. Fifteen days after pesticide application, the control effect of Bb20240406 was 78.83%, still significantly higher than that of other groups of treatments. The control effects of the imidacloprid and thiamethoxam treatments both decreased, and the control effect of thiamethoxam was the lowest at 49.35%.

[0090] Table 9 - Control results of the second pesticide application of each treatment on aphids in spring peanut fields

[0091]

[0092] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0093] The control effects of each treatment on Bemisia tabaci after the second application are shown in Table 10. Before application, there were no significant differences among the treatments. Three days after application, the control effects of 25% thiamethoxam water dispersible granules (II-3) and 25% imidacloprid wettable powder (II-4) were 80.71% and 78.64%, respectively, and there was no significant difference between them, but they were significantly higher than those of 60 g / L spinetoram suspension concentrate (II-1) and Beauveria bassiana Bb20240406 applied at 45 trillion spores / hm 2 (II-2). Seven days after application, the control effect of Beauveria bassiana Bb20240406 increased to 74.46%, which was significantly higher than that of other chemical treatments. The control effect of spinetoram was the lowest, at 62.23%. Ten days after application, the control effect of Beauveria bassiana Bb20240406 was 77.58%, while the control effects of the other groups decreased. Fifteen days after application, the control effect of Beauveria bassiana Bb20240406 was 73.54%, which was significantly higher than that of the other groups; there was no significant difference in the control effects of thiamethoxam and imidacloprid, which were 65.70% and 66.72%, respectively.

[0094] Table 10 - Control results of the second application of each treatment on Bemisia tabaci in spring peanut fields

[0095]

[0096] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0097] The protection results of strain Bb20240406 on peanut leaves after the second application are shown in Table 11. In Table 11, treatments 1 to 5 are 60 g / L spinetoram suspension concentrate, 45 trillion spores / hm 2 Beauveria bassiana Bb20240406, 25% thiamethoxam water dispersible granules, 25% imidacloprid wettable powder, and water control, respectively. Seven days after application, Beauveria bassiana Bb20240406 was applied at 45 trillion spores / hm 2The corrected leaf retention effect was 50.21%, significantly higher than that of other treatment groups and better than the leaf retention effect 7 days after the first pesticide application. 10 days after pesticide application, the corrected leaf retention effect of Beauveria bassiana Bb20240406 was 62.78%, significantly better than that of 25% thiamethoxam water dispersible granules and 25% imidacloprid wettable powder. The corrected leaf retention effect of 60 g / L spinetoram suspension was significantly lower than that of the other three treatment groups, at 40.42%. 15 days after pesticide application, the corrected leaf retention effect of Beauveria bassiana Bb20240406 was 60.32%, significantly higher than that of other treatments, and there was no significant difference among the other three treatment groups.

[0098] Table 11 - Leaf retention effects of the second pesticide application in each treatment on spring peanut fields

[0099]

[0100] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level tested by Duncan's multiple comparison method.

[0101] III. Yield increase effects of Beauveria bassiana Bb20240406 in controlling aboveground pests in spring peanut fields

[0102] The yield increase effects of strain Bb20240406 on peanuts are shown in Table 12. The yield of the Beauveria bassiana Bb20240406 treatment was 4503.89 kg / hm 2 , and the yield of 25% thiamethoxam water dispersible granules was 4430.55 kg / hm 2 . There was no significant difference between the two treatment groups, but it was significantly higher than other treatments and the water control. The yield increase effect of 25% thiamethoxam water dispersible granules was 13.46%, and the yield increase effect of the Bb20240406 treatment was 15.34%. There was no significant difference between the two, and both were significantly higher than other treatments.

[0103] Table 12 - Determination results of spring peanut yields under different treatments

[0104]

[0105] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level tested by Duncan's multiple comparison method.

[0106] IV. Effects on natural enemies after applying Beauveria bassiana in peanut fields

[0107] To further explore the effects of chemical pesticide treatments and Beauveria bassiana treatments on natural enemies in peanut fields, Orius sauteri ( O.sauteriUsing [survey subjects], evaluate the harm of each treatment to natural enemies. Before applying pesticides, investigate the number of pests, and on the 3rd, 7th, 10th, and 15th days after pesticide application, investigate the number of Orius sauteri in each peanut field, and analyze and evaluate the ecological risks of Beauveria bassiana with high virulence, 25% imidacloprid wettable powder, 25% thiamethoxam water dispersible granule, and 60 g / L spinetoram suspension concentrate to Orius sauteri.

[0108] The investigation results of the effects of different treatments on Orius sauteri are as Figure 1 shown. From Figure 1 it can be seen that when 3 days after pesticide application, the number of Orius sauteri in each treatment decreased. Among them, the decrease in the treatment area of Beauveria bassiana Bb20240406 with 45 trillion spores / hm 2 was not significant, while the number of Orius sauteri in the treatment area of 25% imidacloprid wettable powder decreased significantly, and the number in the treatment area of 60 g / L spinetoram suspension concentrate was higher than that of the other two groups of pesticide treatments; 7 days after pesticide application, the number of Orius sauteri in the treatment area of Beauveria bassiana Bb20240406 with 45 trillion spores / hm 2 showed an obvious downward trend, while the other several groups of pesticide treatments increased; 10 days after pesticide application, the number of pests in the treatment area of Beauveria bassiana Bb20240406 did not fluctuate significantly, while the number of Orius sauteri in the other three groups of pesticide treatment areas decreased; 15 days after pesticide application, the number of Orius sauteri from high to low was the treatment area of Bb20240406, 60 g / L spinetoram suspension concentrate treatment, 25% imidacloprid wettable powder treatment, 25% thiamethoxam water dispersible granule treatment, and the number of Orius sauteri in the treatment area of Beauveria bassiana Bb20240406 was significantly higher than that of the other several groups of pesticide treatments.

[0109] V. Study on the antagonistic effect of Beauveria bassiana Bb20240406 against Fusarium solani

[0110] Using the plate confrontation method, use a punch with a diameter of 0.7 mm to punch the peanut pathogen, place the pathogen disc in the center of the culture dish, and place small filter papers with the same diameter dipped in 1×10 8 spores / mL spore suspension in four directions of the pathogen disc, with a distance of 2.5 cm. Set the culture dish with only the pathogen disc as the control, repeat each treatment four times, observe once every 24 h in an incubator, measure the colony radius in four directions, and record the data.

[0111] The results of the confrontation culture of Bb20240406 and Fusarium solani (Table 13) showed that the Bb20240406 strain had a certain inhibitory effect on Fusarium solani, as shown specifically in Figure 2 . The inhibition rate was the highest on the 7th day, reaching 62.22%, which was significantly higher than that of other strains.

[0112] Table 13 - Inhibitory effect of confrontation culture of Beauveria bassiana Bb20240406 on the growth of Fusarium solani

[0113]

[0114] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0115] VI. Antagonistic effect of Beauveria bassiana Bb20240406 against Neocosmospora vasinfecta

[0116] Using the plate confrontation method, a puncher with a diameter of 0.7 mm was used to punch the peanut pathogen. The pathogen discs were placed upside down in the center of the petri dish. Small filter paper discs with the same diameter dipped in a spore suspension of 1×10 8 CFU / mL were placed in four directions of the pathogen discs at a distance of 2.5 cm. The petri dish with only the pathogen disc was set as the control. Each treatment was repeated four times. It was observed once every 24 h after being placed in a constant temperature incubator. The colony radius in four directions was measured and the data were recorded.

[0117] The results of the confrontation culture of Bb20240406 and Neocosmospora vasinfecta on the plate (Table 14) showed that Beauveria bassiana Bb20240406 had a certain antagonistic effect on Neocosmospora vasinfecta causing peanut fruit rot. See the appendix for details Figure 3 . On the 7th day, the inhibition rate of strain Bb20240406 reached 63.02%. When Beauveria bassiana Bb20240406 and Neocosmospora vasinfecta were co - cultured for 3 days, it was observed that Beauveria bassiana had an obvious inhibitory effect on the mycelial growth of the fruit rot pathogen, and the mycelial growth in the direction of the line connecting the inoculation points of the two fungi was extremely slow or even stopped growing.

[0118] Table 14 - Inhibitory effect of confrontation culture of Bb20240406 on the growth of Neocosmospora vasinfecta

[0119]

[0120] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0121] VII. Study on the field control effect of Beauveria bassiana Bb20240406 against peanut fruit rot

[0122] The control experiments of Beauveria bassiana Bb20240406 and Metarhizium anisopliae against peanut fruit rot were carried out in Qian'an, Tangshan. The highly virulent strains and the solid fermentation materials of M18 - 8 - 4 were obtained by liquid - solid biphasic fermentation method, and the concentration of conidia was measured. Before sowing, according to the test - set concentration, the solid fermentation materials of the two strains were weighed and evenly spread into the peanut sowing furrows. The same weight of wheat bran was weighed as the control, and each treatment was repeated 3 times. Each treatment was applied with pesticides for control according to the treatment methods and dosage of pesticides in Table 15. When the peanuts were harvested, the pod damage situation and yield were investigated according to Table 16.

[0123] Table 15 - Dosage and application method of pesticides for the field control experiment of peanut fruit rot

[0124]

[0125] Table 16 - Grading standards for peanut pod diseases

[0126]

[0127] According to the results of in - vitro plate confrontation test, the strain Beauveria bassiana Bb20240406 was selected to control peanut fruit rot in the field. The test results (Table 17) showed that the control effect of Beauveria bassiana Bb20240406 applied at 67.5 trillion spores / hm 2 (I - 4) was the best, which was 66.92%, significantly higher than other treatments. The control effect of M18 - 8 - 4 at 15 trillion spores / hm 2 (I - 1) was the lowest among the four treatments, which was 43.30%. The yields of treatment I - 4 and Metarhizium anisopliae M18 - 8 - 4 applied at 30 trillion spores / hm 2 (I - 2) were 5960.63 kg / hm 2 and 5937.25 kg / hm 2 , significantly higher than other treatments.

[0128] Table 17 - Control effects of biocontrol strains against peanut fruit rot

[0129]

[0130] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0131] VIII. Antagonistic effect of Beauveria bassiana against Fusarium oxysporum

[0132] From the results of the confrontation test of Beauveria bassiana against peanut root rot pathogen (Table 18), it can be seen that Bb20240406 has a certain inhibitory effect on Fusarium oxysporum. See the specific content in Figure 4. On the 3rd day, Bb20240406 had a significant inhibitory effect on Fusarium oxysporum, the pathogen causing peanut root rot. On the 7th day, the inhibition rate of Bb20240406 was 64.35%.

[0133] Table 18 - Inhibitory effect of Beauveria bassiana on the growth of Fusarium oxysporum in plate confrontation culture

[0134]

[0135] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0136] IX. Control effect of Beauveria bassiana Bb20240406 on potted root rot

[0137] The strain of Beauveria bassiana Bb20240406 was selected for the potted control experiment. The results are shown in Table 19. The emergence rate and seedling formation rate of Beauveria bassiana Bb20240406 applied at 6 trillion spores / hm2 (Treatment I-3) were significantly higher than those of other treatment groups, being 87.04% and 87.96% respectively. The incidence rate of 62.5 g / L fluxapyroxad·fludioxonil suspension seed coating agent (Treatment I-4) was 52.16%, significantly lower than that of other treatment groups. Among them, the incidence rate of the water control (Treatment I-5) reached 100%. The control effect of Treatment I-3 was 74.33%, significantly higher than that of other treatments. The high-virulence strain at 2 trillion spores / hm2 (Treatment I-1), the high-virulence strain at 4 trillion spores / hm2 (Treatment I-2), and Treatment I-4 all had certain control effects on peanut root rot, being 37.56%, 60.74%, and 65.15% respectively.

[0138] Table 19 - Control effect of the excellent strain Bb20240406 on peanut root rot

[0139]

[0140] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0141] X. Antagonistic effect of biocontrol bacteria against Sclerotium rolfsii

[0142] Beauveria bassiana Bb20240406, the preserved Metarhizium anisopliae M18-8-4, and three commonly used biocontrol bacteria in production were selected to confront Sclerotium rolfsii. The results are listed in Table 20. See the attachment for details. Figure 5As can be seen from Table 20, on the 2nd day, the inhibition rates of Beauveria bassiana Bb20240406 and Bacillus subtilis were the highest, significantly higher than those of other strains, being 34.60% and 41.40% respectively; the inhibition rates of Trichoderma harzianum and Bacillus megaterium against Sclerotium rolfsii were significantly lower than those of other biocontrol strains, being 13.98% and 12.24% respectively. On the 3rd day, the inhibitory effect of Bacillus subtilis was significantly higher than that of other strains, being 60.82%; the inhibitory effect of Beauveria bassiana Bb20240406 was second only to Bacillus subtilis, being 54.39%; Trichoderma and Bacillus megaterium did not show inhibitory effects on Sclerotium rolfsii.

[0143] Table 20 - Inhibitory effects of biocontrol bacteria in plate confrontation culture on the growth of Sclerotium rolfsii

[0144]

[0145] Note: The data in the table are mean ± standard error, and different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0146] XI. Control effect of Beauveria bassiana Bb20240406 on peanut brown spot

[0147] The control effects of different treatments on peanut brown spot are shown in Table 21. Before spraying, there were no significant differences in the disease indices of each treatment. When investigated after spraying, it was found that the disease index of Beauveria bassiana Bb20240406 applied at 135 trillion spores / hm2 was 4.68%, significantly lower than that of other treatments. The disease index of Beauveria bassiana Bb20240406 applied at 45 trillion spores / hm2 was the highest, being 7.80%. Among them, the control effect of Beauveria bassiana Bb20240406 applied at 135 trillion spores / hm2 was the highest, significantly higher than that of other treatments, being 54.32%, and the control effect of 300 g / L benzovindiflupyr + propiconazole was 48.61%.

[0148] Table 21 - Control results of Beauveria bassiana Bb20240406 on peanut brown spot

[0149]

[0150] Note: The data in the table are mean ± standard error, and different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0151] XII. Control effect of Beauveria bassiana Bb20240406 on peanut black spot

[0152] The control effects of different treatments on peanut black spot disease are shown in Table 22. Before applying the pesticides, there were no significant differences in the disease indices among the treatments. When the investigation was carried out after applying the pesticides, it was found that the disease index of Beauveria bassiana Bb20240406 at the application rate of 135 trillion spores / hm 2 was 11.55%, significantly lower than that of other treatments, and the control effect was 63.88%. The disease index of 300 g / L benzovindiflupyr + propiconazole was significantly lower than that of the other two groups of treatments, and the control effect was 56.12%.

[0153] Table 22 - Control results of Beauveria bassiana Bb20240406 on peanut black spot disease

[0154]

[0155] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0156] XIII. Yield increase effect of Beauveria bassiana Bb20240406 on peanuts

[0157] The yield increase effect of Beauveria bassiana Bb20240406 in controlling leaf diseases on peanuts is shown in Table 23. The yield of Beauveria bassiana Bb20240406 at the application rate of 135 trillion spores / hm 2 was 4567.44 kg / hm 2 , higher than that of other treatments and the water control. The yield increase effect of 300 g / L benzovindiflupyr + propiconazole was 32.59%, and the yield increase effect of Beauveria bassiana Bb20240406 at the application rate of 135 trillion spores / hm 2 was 39.53%, and the difference between the two was significant.

[0158] Table 23 - Yield increase effect of Beauveria bassiana Bb20240406 in controlling leaf diseases on peanuts[[ID=X]]

[0159]

[0160] Note: The data in the table are mean ± standard error. Different lowercase letters indicate significant differences at the 0.05 level by Duncan's multiple comparison method.

[0161] The foregoing has described the present invention in detail. For those skilled in the art, without departing from the gist and scope of the present invention and without the need for unnecessary experiments, the present invention can be implemented within a relatively wide range under equivalent parameters, concentrations, and conditions. Although specific embodiments of the present invention are given, it should be understood that the present invention can be further improved. In short, according to the principle of the present invention, this application intends to cover any modifications, uses, or improvements of the present invention, including those that depart from the scope disclosed in this application but are made by using conventional techniques known in the art. Some basic features can be applied within the scope of the following appended claims.

Claims

1. Application of Beauveria bassiana strain Bb20240406 in controlling peanut fruit rot, peanut root rot, peanut brown spot or peanut black spot, characterized in that, Beauveria bassiana The strain Bb20240406 is classified and named as Beauveria bassiana Beauveria bassiana , preservation number: CGMCC No. 41802, and was preserved in the China General Microbiological Culture Collection Center on January 21, 2025.

2. Use of the fermentation broth or bacterial suspension containing the strain Bb20240406 described in claim 1 in controlling peanut fruit rot, peanut root rot, peanut brown spot or peanut black spot.

3. The application according to claim 2, wherein The active ingredient of the fermentation broth or bacterial suspension of the strain Bb20240406 is the conidia of the strain Bb20240406 described in claim 1.

4. Use of the strain Bb20240406 described in claim 1 or the fermentation broth or bacterial suspension described in claim 2 in inhibiting peanut pathogenic bacteria, wherein the peanut pathogenic bacteria include: Fusarium solani Fusarium solani ), Neocosmospora vasinfecta Neonectria invadens ), Sclerotium rolfsii Sclerotium rolfsii ).

5. Use of the strain Bb20240406 described in claim 1 or the fermentation broth or bacterial suspension described in claim 2 in promoting peanut fruit setting and yield increase.

6. A microbial agent for promoting peanut fruit setting and increasing yield, characterized in that, The active ingredient of the microbial agent includes the strain Bb20240406 described in claim 1.

7. Use of the strain Bb20240406 described in claim 1 or the microbial agent for promoting peanut fruit setting and yield increase described in claim 6 in the production of bio-organic fertilizer.

8. A biological organic fertilizer, characterized in that, The bio-organic fertilizer contains the strain Bb20240406 described in claim 1 or the microbial agent for promoting peanut fruit setting and yield increase described in claim 6.

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