Beauveria bassiana Bb20240406 and application thereof in pest control

Abstract

The invention relates to the technical field of microorganisms, and discloses a Beauveria bassiana strain Bb20240406 and an application of the Beauveria bassiana strain Bb20240406 in prevention and control of diseases and insect pests, and the preservation number of the Beauveria bassiana strain Bb20240406 is CGMCC No.41802. The strain has high insecticidal activity on ground pests and underground pests of peanuts, and has a good control effect; the strain has a strong inhibition effect on pathogenic bacteria of peanut fruit rot, root rot, southern blight and leaf diseases, and has a good field control effect. In addition, the influence of the strain on the population number of orius sauliginosus is lower than that of a conventional chemical pesticide. When the strain provided by the invention is applied to production, the dosage and the use frequency of chemical pesticides can be reduced, and the problems of pesticide residues of agricultural products and environmental pollution are solved; the influence on the number of natural enemy populations is reduced, the farmland ecological environment is protected, and ecological balance is maintained.

Description

Technical Field

[0001] The 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 there are relatively few studies on plant disease control. 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 the onion-specific type of Fusarium oxysporum ( 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 mechanism by which Beauveria bassiana inhibits soil-borne pathogens, showing that it antagonizes pathogens mainly through competition and resistance. Other studies have found that Beauveria bassiana has an inhibitory effect on the mycelial growth of rapeseed sclerotinia, cotton wilt, and wheat fusarium, with an inhibition rate of more than 50% on the third day.

[0003] Peanut is an important oil crop in my country. In recent years, the economic comparative benefits of peanut planting are obvious. The planting area has gradually expanded, resulting in obvious continuous cropping. In addition, factors such as complex and changeable climatic conditions have led to the gradual increase in the occurrence of peanut diseases and insect pests, which seriously affects the yield and quality of peanuts. Common pests such as western flower thrips, peanut aphids, white grubs, beet armyworms, etc., as well as leaf spot, root rot, fruit rot, white rot and other diseases have caused huge losses to peanut production.

[0004] At present, chemical pesticides are the main means of controlling peanut diseases and pests, but long-term use leads to increased resistance of pests and diseases, causing pesticide residues in agricultural products and environmental pollution, and destroying the ecological balance of farmland. Therefore, it is urgent to develop safe, efficient and environmentally friendly biological control methods. Providing efficient Beauveria bassiana strains and their applications for excellent peanut germplasm is an urgent problem to be solved by 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 peanut pests 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 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.

[0006] To achieve the above objectives, the technical solutions provided by the present invention are as follows: In the first aspect of the present invention, a Beauveria bassiana Bb20240406 strain is provided. 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 , and the preservation unit is the General Microbiology Center of the China Committee for Culture Collection of Microorganisms, with the address being Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing 100101, and the postal code: 100101, and the phone number: 8610 - 64807355.

[0007] In the second aspect of the present invention, a fermentation broth, bacterial suspension, sterile supernatant, or its preparation containing the above-mentioned Beauveria bassiana Bb20240406 strain is provided.

[0008] In the third aspect of the present invention, the application of the above-mentioned Beauveria bassiana Bb20240406 strain or the above-mentioned fermentation broth, bacterial suspension, sterile supernatant, or its preparation in the prevention and control of Frankliniella occidentalis, Aphis craccivora, Holotrichia parallela larvae, Spodoptera exigua, and Bemisia tabaci is provided.

[0009] In the fourth aspect of the present invention, the application of the above-mentioned Beauveria bassiana Bb20240406 strain or the above-mentioned fermentation broth, bacterial suspension, sterile supernatant, or its preparation in the prevention and control of peanut fruit rot, peanut root rot, peanut southern blight, peanut brown spot, and peanut black spot is provided.

[0010] In the fifth aspect of the present invention, the application of the above-mentioned Beauveria bassiana Bb20240406 strain or the above-mentioned fermentation broth, bacterial suspension, sterile supernatant, or its preparation in inhibiting peanut pathogens is provided, and the peanut pathogens are: Fusarium solani ( Fusarium solani ), Neocosmospora vasinfecta ( Neonectria invadens ), Sclerotium rolfsii ( Sclerotium rolfsii ) The sixth aspect of the present invention provides the application of the Beauveria bassiana strain Bb20240406 described above, or the fermentation broth, bacterial suspension, sterile supernatant thereof, or its preparation in promoting peanut fruit setting and increasing yield.

[0011] The seventh aspect of the present invention provides a bacterial agent for promoting peanut fruit setting and increasing yield, and the active ingredient of the bacterial agent includes the Beauveria bassiana strain Bb20240406 described above.

[0012] The eighth aspect of the present invention provides the application of the Beauveria bassiana strain Bb20240406 described above, or the bacterial agent for promoting peanut fruit setting and increasing yield described above in the production of biological organic fertilizer.

[0013] The ninth aspect of the present invention provides a biological organic fertilizer, and the biological organic fertilizer contains the Beauveria bassiana strain Bb20240406 described above or the bacterial agent for promoting peanut fruit setting and increasing yield described above.

[0014] Compared with the prior art, the present invention has the following advantages: (1) The control effect of pests and diseases is remarkable (1) Pest control Efficient control of multiple pests: The Beauveria bassiana strain Bb20240406 shows excellent virulence against the main pests common in peanut fields, such as Frankliniella occidentalis, Aphis craccivora, Holotrichia oblita, and Spodoptera exigua. 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.

[0015] 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.

[0016] Wide applicability in different plots and sowing periods: The results of control experiments carried out in peanut fields in different plots and sowing periods in Baoding City show that the Bb20240406 strain can effectively control pests under various planting conditions. For example, in different environments such as greenhouses with high pest population density, spring peanut fields with serious Holotrichia oblita occurrence 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 a reliable guarantee for the safe production of peanuts.

[0017] (2) Disease control Significant pathogen inhibition: The confrontation test on the Petri dish showed that the inhibition rate of Beauveria bassiana Bb20240406 against the pathogens of peanut fruit rot and root rot was significantly higher than that of other strains. This means that this strain can effectively inhibit the growth and reproduction of pathogens, reducing the occurrence and spread of diseases.

[0018] Good control effects on multiple diseases: In the field and pot control tests, the Bb20240406 strain had significant control effects on peanut fruit rot, root rot, and leaf diseases (such as brown spot and black spot). When used to control fruit rot in the peanut field in Luan County, Tangshan, at a dosage of 67.5 trillion spores / hm², the control effect was significant; in the pot test for controlling root rot, when the spore content was 6 trillion spores / hm², the control effect was significant; when spraying to control peanut brown spot and black spot, at a dosage of 135 trillion spores / hm², the control effect was significantly higher than that of common chemical pesticides. By effectively controlling diseases, the healthy growth of peanut plants was ensured, and the yield and quality of peanuts were improved.

[0019] (II) Outstanding environmental protection advantages Reduction in the use of chemical pesticides: The Beauveria bassiana Bb20240406 strain provided by this invention can be an effective substitute for chemical pesticides and plays an important role in the control of peanut pests and diseases. Using this strain can reduce the dosage and frequency of chemical pesticides, reducing the environmental pollution risk caused by the large-scale use of chemical pesticides. For example, in the control test of peanut above-ground pests, the control effect of the Bb20240406 strain in the later stage was better than that of chemical pesticides, indicating that to a certain extent, the dependence on chemical pesticides can be reduced, thereby reducing the residues of chemical pesticides in the soil, water body, and air.

[0020] Reduction of pesticide residues in agricultural products: With the reduction in the use 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.

[0021] Protection of 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 the soil microbial community, water ecosystem, etc., which is conducive to maintaining the balance and stability of the farmland ecosystem.

[0022] (III) Friendly to natural enemies Reducing the harm to 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 Beauveria bassiana Bb20240406 has a significantly lower impact on the number of Orius sauteri than chemical pesticides such as 25% imidacloprid wettable powder, 25% thiamethoxam water dispersible granule, and 60g / L spinetoram suspension. At different time points after pesticide application, the decline in the number of Orius sauteri in the Bb20240406 treatment area was not significant. Moreover, 15 days after pesticide application, 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 indicates that this strain can maximize the protection of the population of natural enemy insects such as Orius sauteri while controlling pests and diseases.

[0023] Enhancing 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 farmland ecosystems 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.

[0024] (4) Significantly increasing production Improving the quality and yield of peanut pods: Through the effective control of peanut pests and diseases, the strain Beauveria bassiana Bb20240406 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-increasing 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 benefits for farmers.

[0025] Ensuring 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 strain Beauveria bassiana Bb20240406 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 and farmers' income increase. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or 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 also be obtained based on the provided drawings.

[0027] Figure 1It is the dynamic growth and decline curve of Orius sauteri after pesticide application; Figure 2 It is the confrontation culture colony of Fusarium solani and Beauveria bassiana Bb20240406; Figure 3 It is the confrontation culture colony of Neocosmospora vasinfecta and Beauveria bassiana Bb20240406; Figure 4 It is the confrontation culture colony of Fusarium oxysporum and Beauveria bassiana Bb20240406; Figure 5 It is the confrontation culture of 5 biocontrol bacteria and Sclerotium rolfsii: Figure 5 In it, a represents the confrontation culture colony of Trichoderma harzianum and Sclerotium rolfsii; Figure 5 In it, b represents the confrontation culture colony of Bacillus megaterium and Sclerotium rolfsii; Figure 5 In it, c represents the confrontation culture colony of Bacillus subtilis and Sclerotium rolfsii; Figure 5 In it, d represents the confrontation culture colony of Beauveria bassiana Bb20240406 and Sclerotium rolfsii; Figure 5 In it, e represents the confrontation culture colony of Metarhizium anisopliae M18-8-4 and Sclerotium rolfsii; Figure 5 In it, f represents the single culture colony of Sclerotium rolfsii. Specific implementation mode

[0028] The present invention will be further described below in conjunction with the embodiments.

[0029] A strain of the present invention was isolated. 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 Microbiology Center of the China Committee for Culture Collection of Microorganisms on January 21, 2025, and the deposit number is: CGMCC No. 41802.

[0030] This strain has high insecticidal activity against above-ground and underground pests of peanuts and good control effects; this strain 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.

[0031] The following are specific embodiments of the present invention: Example 1: Isolation and identification of Beauveria bassiana ( Beauveria bassiana ) Bb20240406 I. Isolation of Beauveria bassiana The corn borer larvae infected with Beauveria bassiana were surface-sterilized with 75% alcohol for 3 - 5 min in a laminar flow hood. Then they were transferred to a 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 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). Three pieces of the cadaver were placed in each petri dish in a triangular arrangement. They were cultured in an incubator at 26°C for 10 d until the insect bodies were covered with white mycelia. The pure white 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 then stored in a refrigerator at 4°C.

[0032] II. Identification and classification at the molecular level based on ITS sequence characteristics 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, which is the ITS sequence of Bb20240406. 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.

[0033] The ITS sequence of Bb20240406 was obtained by sequencing (see SEQ ID No. 1). The ITS sequence of Bb20240406 was subjected to a homology BLAST comparison in the Genbank database. The results showed that the homology of the ITS sequence of the strain Bb20240406 of the present invention with the ITS sequence of Beauveria bassiana was above 99%. At the same time, a phylogenetic tree was constructed using MEGA software, and the strain Bb20240406 of the present invention was clustered together with Beauveria bassiana, indicating that Bb20240406 belongs to Beauveria bassiana in the genus Beauveria in terms of classification.

[0034] Example 2: Biological characteristics of Beauveria bassiana ( Beauveria bassiana ) Bb20240406 I. Study on the control effect of Beauveria bassiana strain Bb20240406 on the white grubs in spring peanut fields in farmland Using Beauveria bassiana strain Bb20240406 as the inoculum, solid fermentation material was obtained through liquid-solid biphasic fermentation, and the content of conidia was determined. Before sowing, the solid fermentation material was weighed according to the conidia dosage designed in the experimental treatment, diluted with wheat bran and evenly spread into the peanut sowing furrows, with an equal amount of wheat bran as the control; the area of the field plot was 30 m2, and each treatment was arranged in a randomized block design with 3 replicates. One day before peanut harvest, the five-point sampling method was used for investigation, with a sampling area of 1 m2, and the damage situation of peanut pods was investigated. The specific grading criteria were as follows: (Grade 0: the pods were intact without damage symptoms; Grade 1: the pericarp was damaged and the kernels were intact; Grade 2: less than half of the kernels were damaged; Grade 3: more than half of the kernels were damaged). The pod damage index, yield, control effect, etc. were calculated respectively.

[0035] The experiment was carried out from May to September 2019 in Xiwuyao Village, Wuyao Township, Lianchi District, Baoding City, Hebei Province. The peanut variety was Jihua 6. The farmland vegetation was single, mostly crops such as wheat and corn. Peanuts had been continuously planted in the experimental field for years, and the occurrence of white grubs was relatively serious all year round. The experimental treatment methods and chemical agent dosages are shown in Table 1.

[0036] Table 1 - Dosage and application method of pesticides for controlling white grubs in spring peanuts in farmland

[0037] The results of controlling white grubs in spring peanut fields in farmland are shown in Table 2. The control effect of Beauveria bassiana Bb20240406 applied at 600 trillion spores / hm 2 (II-2) was 84.88%, and the fruit protection effect was 80.34%, which was significantly higher than other treatments. Its yield was 4209.33 kg / hm 2 , and there was no significant difference from the yield of 4026.00 kg / hm 2 treated with 30% phoxim microcapsule suspension (II-6). 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) had no significant difference in control effect, and the yields were 4114.00 kg / hm 2 , 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 other treatments. When investigating the number of insect populations in the field (Table 3), it was found that the control effect of treatment II-2 was 50.00%, which was significantly higher than other treatments, and the control effect of treatment II-3 was significantly lower than other treatments.

[0038] Table 2 - Control results of Beauveria bassiana Bb20240406 on white grubs in spring peanut fields in farmland

[0039] 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.

[0040] Table 3 - Effects of Beauveria bassiana Bb20240406 on the population of white grubs in spring peanut fields

[0041] 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.

[0042] II. Study on the control effect of highly virulent strains on above-ground pests in peanut fields

[0043] 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 dosages are shown in Table 4. Before the experiment, the solid fermentation material of the highly virulent strain was obtained by 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 containing 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 wet on the peanut leaves. Before applying the medicine, the species and population base of pests 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 number of western flower thrips, aphids, and whiteflies on the top five newly compound leaves, and at the same time, the number of damaged leaves and the damage grade were investigated. The grading standard for peanut leaf damage is shown in Table 10.

[0044] Table 4 - Chemical dosages for field control efficacy tests of above-ground pests in peanut fields

[0045] 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.

[0046] (1) Study on the effect of the first application of highly virulent strains on controlling above-ground pests in spring peanut fields The experiment was sprayed for the first time according to the treatment methods and chemical dosages in Table 4. The population base was investigated before applying the medicine, and the control efficacy was investigated on the 3rd, 7th, 10th, and 15th days after applying the medicine.

[0047] The control effects of different treatments on Frankliniella occidentalis in peanuts are shown in Table 5. Before spraying, there were no significant differences among the treatments. Three days after spraying, the control effect of 60 g / L spinetoram suspension concentrate (I-1) was 79.05%, significantly higher than that of other treatments. The control effects of 25% thiamethoxam water dispersible granule (I-3) and 25% imidacloprid wettable powder (I-4) were 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 spraying, the control effect of Beauveria bassiana Bb20240406 showed an upward trend, and there were no significant differences among the four treatments. Ten days after spraying, the control effect of Beauveria bassiana Bb20240406 increased and was significantly higher than that of other treatments, with a control effect of 79.30%. Fifteen days after spraying, the control effect of Beauveria bassiana Bb20240406 increased to 86.52%, significantly higher than that of other treatments; the control effects of spinetoram and thiamethoxam decreased to 64.04% and 62.75% respectively, and there was no significant difference between them, both were significantly higher than that of imidacloprid, and the control effect of imidacloprid was 54.03%, showing an obvious decrease.

[0048] Table 5 - Control results of the first spraying of each treatment on Frankliniella occidentalis in spring peanut fields

[0049] 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.

[0050] The control results of different treatments on peanut aphids are shown in Table 6. Before spraying, there were no significant differences among the treatments. Three days after spraying, there was no significant difference in the control effects of 25% thiamethoxam water dispersible granule (I-3) and 25% imidacloprid wettable powder (I-4), which were 83.43% and 84.94% respectively, significantly higher than that of 60 g / L spinetoram suspension concentrate (I-1) and Beauveria bassiana Bb20240406 at 45 trillion spores / hm 2 ² (I-2). Seven days after spraying, the control effect of Beauveria bassiana Bb20240406 increased to 68.93%, significantly higher than that of other treatments. Ten days after spraying, the control effect of Beauveria bassiana Bb20240406 was significantly higher than that of other groups, at 87.14%. Fifteen days after spraying, the control effect of Beauveria bassiana Bb20240406 decreased slightly to 76.94%, still significantly higher than that of other groups; the control effects were in the order of thiamethoxam > imidacloprid > spinetoram.

[0051] Table 6 - Control results of the first spraying of each treatment on aphids in spring peanut fields

[0052] 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.

[0053] 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 is 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 is the lowest, at 34.09%. At 10 days after spraying, there is no significant difference in the corrected leaf protection effects of Beauveria bassiana Bb20240406, spinetoram, and imidacloprid, which are 56.02%, 48.17%, and 49.22% respectively, significantly higher than thiamethoxam. At 15 days after spraying, the corrected leaf protection effect of Beauveria bassiana Bb20240406 is significantly higher than other treatments, at 65.88%. Followed by spinetoram, at 55.62%.

[0054] Table 7 - Leaf protection effects of the first pesticide application for each treatment on spring peanut fields

[0055] 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.

[0056] (2) Study on the control effect of highly virulent strains in the second pesticide application against above-ground pests in spring peanut fields The test was sprayed according to the treatment methods and dosages in Table 4 for the second time. The test 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.

[0057] The control effects of each treatment on Frankliniella occidentalis in peanut fields after the second pesticide application are shown in Table 8. Before spraying, there was no significant difference among the treatments. At 3 days after spraying, the control effect of 60 g / L spinetoram suspension concentrate (II-1) was 81.43%, significantly higher than other treatments. The control effects of 25% thiamethoxam water dispersible granule (II-3) and 25% imidacloprid wettable powder (II-4) were 68.05% and 69.50% respectively, significantly higher than Beauveria bassiana Bb20240406 at 45 trillion spores / hm 2Control effect of (II-2). 7 days after spraying, there was no significant difference in the control effects of Beauveria bassiana Bb20240406 and spinetoram, which were 69.66% and 66.61% respectively. There was no significant difference in the control effects of thiamethoxam and imidacloprid. 10 days after spraying, the control effect of Beauveria bassiana B16-5 increased, significantly higher than that of other treatments, and the control effect was 71.44%. 15 days after spraying, the control effect of Beauveria bassiana B16-5 treatment increased to 74.46%, significantly higher than that of other treatments; there was no significant difference in the control effects of spinetoram, thiamethoxam and imidacloprid.

[0058] Table 8 - Control results of the second pesticide application on Frankliniella occidentalis in spring peanut fields for each treatment

[0059] 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.

[0060] The control effects of each treatment on peanut aphids after the second pesticide application are shown in Table 9. Before spraying, there was no significant difference among the treatments. 3 days after spraying, the control effects of 25% thiamethoxam water dispersible granule (II-3) and 25% imidacloprid wettable powder (II-4) were 72.44% and 73.68% 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). 7 days after spraying, the control effect of Beauveria bassiana Bb20240406 increased, significantly higher than that of other pesticide treatments, reaching 70.73%, and there was no significant difference among the other groups of treatments. 10 days after spraying, the control effect of Bb20240406 was 82.01%, significantly higher than that of other groups of treatments. 15 days after spraying, the control effect of Bb20240406 was 78.83%, still significantly higher than that of other groups of treatments. The control effects of imidacloprid and thiamethoxam treatments both decreased, and the control effect of thiamethoxam was the lowest at 49.35%.

[0061] Table 9 - Control results of the second pesticide application on aphids in spring peanut fields for each treatment

[0062] 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.

[0063] The control effects of each treatment on Bemisia tabaci after the second pesticide application are shown in Table 10. Before pesticide application, there were no significant differences among the treatments. Three days after pesticide 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 2

[0064] Table 10 - Control results of the second pesticide application of each treatment on Bemisia tabaci in spring peanut fields

[0065] Note: The data in the table are mean ± standard error, and different lowercase letters indicate significant differences at the 0.05 level tested by Duncan's multiple comparison method.

[0066] The protection results of strain Bb20240406 on peanut leaves after the second pesticide 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 pesticide application, the corrected leaf protection effect of Beauveria bassiana Bb20240406 applied at 45 trillion spores / hm 2 was 50.21%, which was significantly higher than those of other treatments and better than the leaf protection effect 7 days after the first pesticide application. Ten days after pesticide application, the corrected leaf protection effect of Beauveria bassiana Bb20240406 was 62.78%, which was significantly better than that of 25% thiamethoxam water dispersible granules and 25% imidacloprid wettable powder. The corrected leaf protection effect of 60 g / L spinetoram suspension concentrate was significantly lower than those of the other three treatments, at 40.42%. Fifteen days after pesticide application, the corrected leaf protection effect of Beauveria bassiana Bb20240406 was 60.32%, which was significantly higher than that of other treatments, and there was no significant difference among the other three treatments.

[0067] Table 11 - Leaf protection effects of the second pesticide application of each treatment on spring peanut fields

[0068] 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.

[0069] III. Yield increase effect of Beauveria bassiana Bb20240406 in controlling above-ground pests in spring peanut fields

[0070] The yield increase effect of strain Bb20240406 on peanuts is shown in Table 12. The yield of the plot treated with Beauveria bassiana Bb20240406 is 4503.89 kg / hm 2 , and the yield of the 25% thiamethoxam water dispersible granule is 4430.55 kg / hm 2 . There is no significant difference between the two treatments, but it is significantly higher than other treatments and the water control. The yield increase effect of the 25% thiamethoxam water dispersible granule is 13.46%, and that of the Bb20240406 treatment is 15.34%. There is no significant difference between the two, and both are significantly higher than other treatments.

[0071] Table 12 - Determination results of spring peanut yields under different treatments

[0072] 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.

[0073] IV. Impact of applying Beauveria bassiana on natural enemies in peanut fields

[0074] To further explore the impact of chemical pesticide treatments and Beauveria bassiana treatments on natural enemies in peanut fields, Orius sauteri ( O.sauteri ), the dominant natural enemy in peanut fields, was used as the investigation object to evaluate the damage to natural enemies of each treatment. The number of insect populations was investigated before pesticide application, and the number of Orius sauteri in each peanut field was investigated on the 3rd, 7th, 10th, and 15th days after pesticide application to analyze and evaluate the ecological risks of highly virulent Beauveria bassiana, 25% imidacloprid wettable powder, 25% thiamethoxam water dispersible granule, and 60 g / L spinetoram suspension concentrate on Orius sauteri.

[0075] The investigation results of the impact of different treatments on Orius sauteri are as Figure 1 shown. It can be seen from Figure 1 that when 3 days after pesticide application, the number of Orius sauteri in each treatment decreased. Among them, 45 trillion spores / hm 2The decline in the Orius sauteri population in the Beauveria bassiana Bb20240406 treatment area was not significant, while the number of Orius sauteri in the 25% imidacloprid wettable powder treatment area decreased significantly, and the number in the 60 g / L spinetoram suspension concentrate treatment area was higher than that in the other two groups of pesticide treatments; 7 days after pesticide application, 45 trillion spores / hm 2 The number of Orius sauteri in the Beauveria bassiana Bb20240406 treatment area showed an obvious downward trend, while the numbers in the other groups of pesticide treatments all increased; 10 days after pesticide application, the population number in the Beauveria bassiana Bb20240406 treatment area did not show obvious fluctuations, while the number of Orius sauteri in the other three groups of pesticide treatment areas decreased; 15 days after pesticide application, the population numbers of Orius sauteri from high to low were the Beauveria bassiana Bb20240406 treatment area, the 60 g / L spinetoram suspension concentrate treatment, the 25% imidacloprid wettable powder treatment, and the 25% thiamethoxam water dispersible granule treatment, and the number of Orius sauteri in the Beauveria bassiana Bb20240406 treatment area was significantly higher than that in the other groups of pesticide treatments.

[0076] V. Study on the antagonistic effect of Beauveria bassiana Bb20240406 against Fusarium solani Using the plate confrontation method, a punch with a diameter of 0.7 mm was used to punch the peanut pathogen, and the pathogen disc was 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 disc, with a distance of 2.5 cm. The petri dish with only the pathogen disc was set as the control, and 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 was recorded.

[0077] The results of the confrontation culture between 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.

[0078] Table 13 - Inhibitory effect of Bb20240406 on the growth of Fusarium solani in plate confrontation culture

[0079] 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.

[0080] VI. Antagonistic effect of Beauveria bassiana Bb20240406 against Neocosmospora vasinfecta

[0081] Using the plate confrontation method, a punch with a diameter of 0.7 mm was used to punch the peanut pathogen, and the pathogen disc was placed upside down in the center of the petri dish. Small filter paper discs with the same diameter dipped in a spore suspension of 1×108 Small filter paper pieces of the same diameter with a spore suspension of [[X]] spores / mL were placed in four directions around the pathogen disc, at a distance of 2.5 cm. Petri dishes with only the pathogen disc were set as controls. Each treatment was replicated four times and placed in an incubator at a constant temperature. Observation was carried out once every 24 h, the colony radius in four directions was measured, and the data were recorded.

[0082] The results of the confrontation culture of Bb20240406 and Neocosmospora vasinfecta on a flat 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 For the Bb20240406 strain, the inhibition rate reached 63.02% on the 7th day. When Beauveria bassiana Bb20240406 was confronted with Neocosmospora vasinfecta 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 connection line between the inoculation points of the two fungi was extremely slow or even stopped growing.

[0083] Table 14 - Inhibitory effect of Bb20240406 in confrontation culture on the growth of Neocosmospora vasinfecta

[0084] 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.

[0085] VII. Study on the field control effect of Beauveria bassiana Bb20240406 on peanut fruit rot Field control experiments of Bb20240406 and Metarhizium anisopliae on peanut fruit rot were carried out in Qian'an, Tangshan. High-virulence strains and solid fermentation materials of M18-8-4 were obtained by liquid-solid biphasic fermentation, 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 used as the control, and each treatment was replicated 3 times. Each treatment was applied with pesticides for control according to the treatment methods and dosages in Table 15. When the peanuts were harvested, the damage of pods and the yield were investigated according to Table 16.

[0086] Table 15 - Dosage and application method of pesticides in the field control experiment of peanut fruit rot

[0087] Table 16 - Grading standard for peanut pod diseases

[0088] According to the results of in - vitro plate confrontation tests, Beauveria bassiana strain 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 at 67.5 trillion spores / hm 2 (I - 4) was the best, being 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, being 43.30%. The yields of treatment I - 4 and Metarhizium anisopliae M18 - 8 - 4 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.

[0089] Table 17 - Control effects of biocontrol strains on peanut fruit rot

[0090] 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.

[0091] VIII. Antagonistic effect of Beauveria bassiana on Fusarium oxysporum From the results of the confrontation tests of Beauveria bassiana against peanut root rot pathogens (Table 18), it can be seen that Bb20240406 has a certain inhibitory effect on Fusarium oxysporum. See the specific Figure 4 . On the 3rd day, Bb20240406 had a significant inhibitory effect on Fusarium oxysporum, the peanut root rot pathogen. On the 7th day, the inhibition rate of Bb20240406 was 64.35%.

[0092] Table 18 - Inhibitory effect of Beauveria bassiana on the growth of Fusarium oxysporum in plate confrontation culture

[0093] 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.

[0094] IX. Control effect of Beauveria bassiana Bb20240406 on potted root rot The strain Beauveria bassiana Bb20240406 was selected for pot control experiments. 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 the 62.5 g / L metalaxyl·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.

[0095] Table 19 - Control effect of the excellent strain Bb20240406 on peanut root rot

[0096] 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.

[0097] X. Antagonistic effect of biocontrol bacteria against Sclerotium rolfsii 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, as shown in the attachment for details. Figure 5 As 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 inhibition effect of Bacillus subtilis was significantly higher than that of other strains, being 60.82%; the inhibition 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.

[0098] Table 20 - Inhibitory effect of biocontrol bacteria on the growth of Sclerotium rolfsii in plate confrontation culture

[0099] 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.

[0100] XI. Control Effect of Beauveria bassiana Bb20240406 on Peanut Brown Spot The control effects of different treatments on peanut brown spot are shown in Table 21. Before spraying, there was no significant difference in the disease incidence index among the treatments. When investigated after spraying, it was found that the disease index of Beauveria bassiana Bb20240406 applied at 1.35 trillion spores / hm² was 4.68%, significantly lower than that of other treatments. The disease index of Beauveria bassiana Bb20240406 applied at 0.45 trillion spores / hm² was the highest, which was 7.80%. Among them, the control effect of Beauveria bassiana Bb20240406 applied at 1.35 trillion spores / hm² was the highest, significantly higher than that of other treatments, which was 54.32%. The control effect of 300 g / L benzovindiflupyr + propiconazole was 48.61%.

[0101] Table 21 - Control Results of Beauveria bassiana Bb20240406 on Peanut Brown Spot

[0102] 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 test.

[0103] XII. Control Effect of Beauveria bassiana Bb20240406 on Peanut Black Spot The control effects of different treatments on peanut black spot are shown in Table 22. Before spraying, there was no significant difference in the disease incidence index among the treatments. When investigated after spraying, it was found that the disease index of Beauveria bassiana Bb20240406 applied at 1.35 trillion spores / hm 2 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%.

[0104] Table 22 - Control Results of Beauveria bassiana Bb20240406 on Peanut Black Spot

[0105] 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 test.

[0106] XIII. Yield-Increasing Effect of Beauveria bassiana Bb20240406 on Peanut The yield-increasing effect of Beauveria bassiana Bb20240406 in controlling leaf diseases on peanut is shown in Table 23. The yield of Beauveria bassiana Bb20240406 applied at 1.35 trillion spores / hm 2 ² was 4567.44 kg / hm2 , higher than other treatments and the water control. The yield increase effect of 300 g / L benzoconazole prothioconazole was 32.59%, and Beauveria bassiana Bb20240406 was applied at 1.35 trillion spores / hm 2 The yield increase effect was 39.53%, and the difference between the two was significant.

[0107] Table 23 - Yield increase effect of Beauveria bassiana Bb20240406 in controlling leaf diseases on peanuts

[0108] 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.

[0109] The present invention has been described in detail above. For those skilled in the art, without departing from the gist and scope of the present invention and without 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 conventional techniques known in the art. Some basic features can be applied according to the scope of the appended claims below.

Claims

1. Application of Beauveria bassiana strain Bb20240406 in controlling peanut fruit rot, peanut root rot, peanut brown spot and peanut leaf 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, bacterial suspension, sterile supernatant or preparation thereof containing the strain Bb20240406 described in claim 1 in controlling peanut fruit rot, peanut root rot, peanut brown spot and peanut black spot.

3. The application according to claim 2, wherein The active ingredient of the fermentation broth, bacterial suspension, sterile supernatant or preparation thereof 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, bacterial suspension or its sterile supernatant or its preparation 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, bacterial suspension, sterile supernatant or preparation thereof described in claim 2 in promoting peanut fruit retention 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 retention 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 retention and yield increase described in claim 6.

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