Microbial agent for preventing and treating bemisia tabaci and application thereof

Abstract

The invention discloses a microbial agent for preventing and treating bemisia tabaci and application of the microbial agent. The microbial agent is bacillus subtilis MJ-4 fermentation liquor obtained by taking bacillus subtilis MJ-4 as a strain and performing seed activation and fermentation. According to the invention, the bacillus subtilis MJ-4 with insecticidal broad spectrum is used as a biocontrol bacterium for preventing and treating the harm of the bemisia tabaci, aiming at the problems in the existing prevention and treatment, the bemisia tabaci is prevented and treated to generate drug resistance, and the environment-friendly, non-toxic and harmless biological prevention and treatment are realized; the strain MJ-4 is environment-friendly, can be combined with bait, can well attract bemisia tabaci to eat, has a remarkable killing effect, has no adverse effect on vertebrates, and can be developed and utilized as a good biological control fungicide due to the fact that bacterial powder is easy to produce and low in cost.

Description

Technical Field

[0001] This invention belongs to the field of biological control, and relates to a microbial agent for controlling whiteflies and its application. Background Technology

[0002] Whiteflies ( Bemisia tabaci The whitefly is a globally widespread agricultural pest that parasitizes various economic crops, including cotton, vegetables, fruits, and ornamental plants, causing significant economic losses to agricultural production. The whitefly not only harms crops by directly feeding on their sap but also transmits plant diseases through its saliva, further impacting crop growth. Furthermore, the whitefly acts as a vector for many plant viruses, accelerating the spread and dissemination of crop diseases. These characteristics make the whitefly a difficult pest to control, posing a serious challenge to global agriculture.

[0003] Currently, chemical pesticides are the primary means of controlling whiteflies. However, the long-term and extensive use of chemical pesticides has led to a series of problems, including the rapid increase in pesticide resistance in whiteflies and the negative impacts of pesticide residues on the environment and human health. Furthermore, the use of chemical pesticides can also adversely affect non-target organisms in the ecosystem, thereby disrupting the natural balance. Although biological control measures, such as predatory insect enemies, have some effect on suppressing whiteflies, their application is limited by the adaptability of the natural enemies and environmental conditions, resulting in inconsistent effectiveness. Therefore, finding safer, more stable, and more effective methods for controlling whiteflies is an urgent priority. Summary of the Invention

[0004] The purpose of this invention is to provide a microbial agent for controlling whiteflies and its application, so as to solve the technical problem that the existing measures for controlling whiteflies are not effective.

[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a microbial agent for controlling whiteflies. The microbial agent is a Bacillus subtilis MJ-4 fermentation broth obtained by seed activation and fermentation.

[0006] According to a preferred embodiment, the effective viable bacteria count in the microbial agent is 5 × 10⁻⁶. 8 CFU / mL ~ 1×10 11 CFU / mL.

[0007] Secondly, the application of microbial agents for controlling whiteflies, as described in the first aspect, in products for controlling whiteflies.

[0008] The classification and nomenclature of Bacillus provided by this invention is Bacillus subtilis (Bacillus subtilis) Bacillus subtilisMJ-4, with accession number CGMCC No. 30850, is deposited at the China General Microbiological Culture Collection Center on June 3, 2024, and is in viable condition.

[0009] The beneficial effects of this invention are: 1) This strain MJ-4 is environmentally friendly, has no adverse effects on vertebrates, and its powder production is simple and inexpensive, so it can be developed and utilized as a good biological control agent. 2) The strain MJ-4 described in this invention has good contact killing activity against whiteflies on different plants. It can kill whiteflies immediately in a short time. Compared with chemical agents on the market, it has better insecticidal effect. As a microbial agent, it is not easy for whiteflies to develop drug resistance. The mortality rate can reach more than 90%. 3) This invention utilizes a strain of Bacillus subtilis with broad-spectrum insecticidal activity (… Bacillus subtilis MJ-4, a biocontrol bacterium for controlling the rampant whitefly infestation, addresses existing problems in control methods by preventing whiteflies from developing resistance, achieving environmentally friendly, non-toxic, and harmless biological control. It not only provides new ideas and technical means for whitefly control but also promotes the innovation and popularization of microbial control technologies in agricultural production. Attached Figure Description

[0010] Figure 1 Image showing the effect of MJ-4 contact insecticide against whiteflies; Figure 2 The contact toxicity of different concentrations of MJ-4 bacterial solution against tobacco whiteflies was investigated. Figure 3 The repellency of Bacillus subtilis MJ-4 bacterial suspension against tobacco whiteflies; Figure 4 The contact killing speed of Bacillus subtilis MJ-4 against whiteflies; Figure 5 The rapid killing effect of Bacillus cereus MJ-4 bacterial solution on whiteflies; Figure 6 This is a phylogenetic tree of the 16S rDNA, gyrB, and rpoβ sequences of microbial agents. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0012] A microbial agent for controlling whiteflies, the microbial agent being based on Bacillus subtilis (B. subtilis). Bacillus subtilis MJ-4 is the bacterial strain, and the fermentation broth of Bacillus subtilis MJ-4 is obtained through seed activation and fermentation; Bacillus subtilis ( Bacillus subtilis The accession number of MJ-4 is CGMCC No. 30850. This strain is deposited at the China General Microbiological Culture Collection Center; the accession date is June 3, 2024, and the status is viable.

[0013] A microbial agent for controlling whiteflies, wherein the microbial agent is prepared from the fermentation broth of Bacillus subtilis MJ-4 and is in the form of a wettable powder or suspension.

[0014] Bacillus subtilis MJ-4 was isolated from the diseased coleopteran bark beetle and obtained through screening, culture, morphological characteristics, and physiological and biochemical assays.

[0015] The effective viable bacteria count in the microbial agent is 5 × 10⁻⁶. 8 CFU / mL ~ 1×10 11 CFU / mL; among which, when the Bacillus subtilis MJ-4 fermentation broth is prepared as a wettable powder, its effective viable count is 5 × 10⁻⁶. 8 ~1×10 11 CFU / mL; When the Bacillus subtilis MJ-4 fermentation broth is prepared as a suspension, the effective viable count in the Bacillus subtilis MJ-4 fermentation broth is 5 × 10⁻⁶ CFU / mL. 8 ~1×10 10 CFU / mL.

[0016] The microbial inoculant also includes an active agent, which is 1‰ to 4‰ Tween-20.

[0017] The application of microbial agents in products for the control of whiteflies. These microbial agents have repellent, contact, and stomach poison insecticidal activities against all stages of the whitefly.

[0018] The specific method for using microbial agents is as follows: spray the microbial agents evenly on the upper and lower surfaces of crop leaves infested with whiteflies until they are moist. The whiteflies will die quickly, and within one month of spraying the microbial agents, the crop leaves will no longer be infested with whiteflies.

[0019] Example 1 Bacillus subtilis ( Bacillus subtilis MJ-4 screening.

[0020] I. Screening Process This invention relates to the diseased and dead coleopteran insect, the bark beetle (*Pinus tabuliformis*), which cuts the branches of pine trees in horizontal pits. Blastophagus minor Hartig Several suspected pathogenic bacteria were isolated from the organism and the environment. After streak plating and purification, they were cultured in LB broth. The above strains, MJ-4, were then inoculated onto healthy bark beetles one by one to kill them. Gradually, the most virulent strain, MJ-4, was selected. When this strain was inoculated onto whiteflies, it also exhibited strong pathogenicity. This strain, MJ-4, was successfully isolated from dead whiteflies and subsequently reinoculated onto healthy whiteflies, where it remained pathogenic. Therefore, strain MJ-4 was confirmed as the pathogenic bacterium of the whitefly.

[0021] II. Colony Morphology Characteristics and Identification The optimal growth temperature for strain MJ-4 described in this invention is 37 ℃. On LB agar, the colonies are pale yellow with no difference in color between the front and back, slightly transparent, with a rough, dull surface, round or oval edges, and pentagonal or irregular small protrusions. The surface is dry and wrinkled, the cells are viscous but moist, easy to pick up, small and evenly distributed, and accompanied by an unpleasant odor. [The text then abruptly shifts to a different topic:] ...and separately... 16s rDNA , gyrB , rpoB Three pairs of primers were used for PCR amplification to obtain... 16S rDNA The gene sequence is 1028 bp. gyrB The gene sequence is 1348 bp. rpoB The gene sequence is 764 bp. BLAST alignment using multiple primers on the NCBI website showed that strain MJ-4 had a similarity of over 99.9% with Bacillus subtilis. Further analysis of the isolated strain MJ-4... 16S rDNA , gyrB , rpoB Three gene sequences were determined, and morphological identification confirmed that the isolated strain was Bacillus subtilis. Bacillus subtilis MJ-4.

[0022] Example 2 Determination of the contact toxicity and repellency of microbial agents against whiteflies.

[0023] I. Contact Killing: Weigh a certain amount of the Bacillus subtilis MJ-4 microbial agent (wettable powder) of this application and dissolve it in water to adjust the concentration of the microbial solution to 1×10⁻⁶. 10 CFU / mL, 1×10 9 CFU / mL, 1×10 8 Three concentrations of CFU / mL were prepared, and Tween-20 was added to the microbial culture as a surfactant to achieve a concentration of 1‰ to 4‰ before use.

[0024] Contact toxicity tests were conducted on the leaves of three types of tomato plants (tomato, pepper, and tobacco) using Bacillus subtilis MJ-4. The number of whiteflies on each plant before spraying was counted. Different concentrations of the bacterial solution were evenly sprayed onto the upper and lower surfaces of the leaves of plants infested with whiteflies. Although the dead insects showed no obvious signs of life (see details...), the toxicity was determined by spraying the leaves with different concentrations of the bacterial solution onto the upper and lower surfaces of the leaves of plants infested with whiteflies. Figure 1 However, due to their small size, most whiteflies fall to the ground, into dead crops, or into soil crevices after death and are not investigated. Therefore, when calculating the mortality rate, the number of live whiteflies before and after treatment is counted to determine the mortality rate. After covering the plants with insect nets, the whitefly mortality rate is calculated on the third day based on the final number of whiteflies (see the calculation formula below). Data analysis and significance analysis were performed using SPSS software. Each group was repeated three times, with a control group treated with water. The contact mortality rate of Bacillus subtilis MJ-4 bacterial solution on tomatoes, tobacco, and peppers was calculated (see details). Figure 2 ).

[0025] Calculation of prevention and control effectiveness: Mortality rate (%) = (Number of live insects before treatment - Number of live insects after treatment) * 100 / Number of live insects before treatment; Corrected mortality rate (%) = (treatment group mortality rate - blank control mortality rate) * 100 / (100 - blank control mortality rate).

[0026] The results showed that all four concentrations of Bacillus subtilis MJ-4 bacterial suspensions exhibited better contact toxicity than the control group, with 1×10⁻⁶ concentrations showing the best effect. 8 The insecticidal rate of CFU / mL concentration is higher than that of 1×10 11 CFU / mL, 1×10 10 CFU / mL, 1×10 9 The significant decrease in CFU / mL and the large error indicate that 1×10 8 The effectiveness of CFU / mL against whiteflies decreased significantly. Compared to 1×10⁻⁶, the effect was significantly reduced. 11 CFU / mL, 1×10 10 CFU / mL and 1×10 9 The mortality rate of whiteflies at a concentration of CFU / mL, 1×10 9 Although the mortality rate at CFU / mL concentration is lower than that at 1×10 11 CFU / mL, 1×10 10 While treatment with CFU / mL bacterial suspensions reduced mortality, it still maintained a high mortality rate, exceeding 90%. Through comparison, considering effective utilization concentrations and usage costs, 1×10⁻⁶ CFU / mL concentration... 9 The best results were achieved with Bacillus subtilis MJ-4 bacterial suspension treated at a concentration of CFU / mL.

[0027] II. Approach and Avoidance: Weigh out a certain amount of Bacillus subtilis MJ-4 bacterial agent and dissolve it in water. Adjust the bacterial concentration to 1×10⁻⁶ for optimal contact killing of whiteflies. 9 CFU / mL concentration, add Tween-20 as a surfactant to the bacterial culture to achieve a Tween-20 concentration of 1‰~4‰ before use.

[0028] Then, the repellency of Bacillus subtilis MJ-4 inoculum to whiteflies was measured on the leaves of tomato, pepper, and tobacco plants using water-soluble inoculum. Tomato seedlings, pepper plants, and tobacco plants infested with whiteflies were prepared, and the number of whiteflies before treatment was counted. A concentration of 1×10⁻⁶ was used. 9 A uniform spray of Bacillus subtilis MJ-4 bacterial suspension at CFU / mL was used for treatment, while the control group was treated with water. The insect population reduction rate was recorded at 7, 15, and 30 days after treatment (see details). Figure 3 ).

[0029] The results showed that using a concentration of 1×10 9 The repellency rates of tomato, pepper, and tobacco seedlings treated with Bacillus subtilis MJ-4 (CFU / mL) were all positive, and although they decreased slightly over time, they remained above 50%, hovering around 60%. In contrast, the control group showed a negative repellency rate, which continued to decline over time. This indicates that MJ-4 plays a sustained role in controlling whiteflies.

[0030] Example 3 Determination of the killing time of Bacillus subtilis MJ-4 against whiteflies.

[0031] Weigh a certain amount of Bacillus subtilis MJ-4 inoculant (wettable powder or suspension) and dissolve it in water, adjusting the effective viable count of the inoculant solution to 1×10⁻⁶. 9 CFU / mL concentration: Tween-20 is added to the bacterial culture as a surfactant to achieve a concentration of 1‰~4‰ before use.

[0032] Prepare tomato plants infested with whiteflies. Spray the prepared bacterial solution onto the whiteflies, and start timing once the whiteflies' bodies are coated with the solution. During this time, gently touch the whiteflies with a paintbrush and observe them with a magnifying glass to check for signs of life. Stop timing once all signs of life are confirmed, indicating the whiteflies are dead. After observing the mortality time of 30 whiteflies × 3 groups, it was concluded that the mortality time of whiteflies after spraying with Bacillus subtilis MJ-4 bacterial solution is 43–60 seconds (see details). Figure 4 ).

[0033] Example 4 Comparison of the control efficacy of Bacillus subtilis MJ-4 inoculant and plant-derived pesticides against whiteflies.

[0034] (1) Test materials Bacillus subtilis MJ-4 bacterial suspension: prepared with an effective viable count of 1×10⁻⁶. 9 A bacterial solution of CFU / mL was prepared to ensure that it could kill whiteflies upon contact.

[0035] Plant-derived insecticides: Commercially available azadirachtin solution and matrine solution were diluted according to the manufacturer's recommended concentration for testing.

[0036] Test plants: Select healthy tomato plants (5 true leaves stage) and inoculate the same number of adult whiteflies on the leaves.

[0037] The experiment was divided into four groups, with three replicates in each group: MJ-4 group: Spray with 1×10 effective viable bacteria 9 Bacillus subtilis MJ-4 bacterial suspension at CFU / mL was diluted with Tween-20 to achieve a concentration of 1‰~4‰.

[0038] 1% azadirachtin microemulsion group: spray with a 1000-fold dilution of azadirachtin.

[0039] 5% Matrine aqueous solution group: spray with a 625-fold dilution of matrine.

[0040] Control group (CK): Sprayed with an equal amount of Tween-20 aqueous solution containing 1‰~4‰.

[0041] Each group was set up with 3 tomato plants, and each plant was inoculated with the same number of whiteflies (e.g., 40 whiteflies per plant).

[0042] Spray the corresponding treatment solution evenly on each plant, ensuring that every leaf is covered with the treatment solution.

[0043] After treatment, each pot was placed under the same environmental conditions for cultivation.

[0044] Forty-eight hours after the spraying treatment, the number of surviving whiteflies on each tomato plant was counted.

[0045] Calculation of prevention and control effectiveness: Mortality rate (%) = (Number of live worms before treatment - Number of live worms after treatment) * 100 / Number of live worms before treatment Corrected mortality rate (%) = (treatment group mortality rate - blank control mortality rate) * 100 / (100 - blank control mortality rate) The mortality rate and corrected efficacy for each treatment group were calculated, as detailed in Table 1.

[0046] Table 1. Mortality rates of whiteflies treated with Bacillus subtilis MJ-4 inoculant and plant-derived pesticides

[0047] (5) Results Analysis The results showed that azadirachtin solution exhibited the highest insecticidal effect, with an average insecticidal rate of 96.19%, followed by the MJ-4 group with an insecticidal rate of approximately 93.81%, and matrine with an average insecticidal rate of 84.62%. The corrected control efficacies were 93.48%, 95.98%, and 83.79%, respectively. There was no significant difference between the MJ-4 group and the azadirachtin group, but both groups showed significantly higher control efficacy against whiteflies than the matrine group. These results indicate that Bacillus subtilis MJ-4 inoculum has a high insecticidal effect on whiteflies, approaching the insecticidal rate of azadirachtin and superior to matrine, demonstrating the application potential of Bacillus subtilis MJ-4 inoculum for biocontrol and fully illustrating that the Bacillus subtilis MJ-4 inoculum of this invention can replace existing plant-derived drugs for whitefly control.

[0048] Below is the identification sequence number of Bacillus subtilis MJ-4 ( 16S , rpoB , gyrB (Three pairs of primers).

[0049] 16S rDNA: GGGGGTGCTA TAATGCAAGT CGAGCGGACA GATGGGAGCT TGCTCCCTGA TGTTAGCGGC 60 GGACGGGTGA GTAACACGTG GGTAACCTGC CTGTAAGACT GGGATAACTC CGGGAAAACCG 120 GGGCTAATAC CGGATGGTTG TTTGAACCGC ATGGTTCAAA CATAAAAGGT GGCTTCGGCT 180 ACCACTTACA GATGGACCCG CGGCGCATTA GCTAGTTGGT GAGGTAACGG CTCACCAAGG 240 CAACGATGCG TAGCCGACCT GAGAGGGTGA TCGGCCACAC TGGGACTGAG ACACGGCCCA 300 GACTCCTACG GGAGGCAGCA GTAGGGAATC TTCCGCAATG GACGAAAGTC TGACGGAGCA 360 ACGCCGCGTG AGTGATGAAG GTTTTCGGAT CGTAAAGCTC TGTTGTTAGG GAAGAACAAG 420 TACCGTTCGA ATAGGGCGGT ACCTTGACGG TACCTAACCA GAAAGCCACG GCTAACTACG 480 TGCCAGCAGC CGCGGTAATA CGTAGGTGGC AAGCGTTGTC CGGAATTATT GGGCGTAAAG 540 GGCTCGCAGG CGGTTTCTTA AGTCTGATGT GAAAGCCCCC GGCTCAACCG GGGAGGGTCA 600 TTGGAAACTG GGGAACTTGA GTGCAGAAGA GGAGAGTGGA ATTCCACGTG TAGCGGTGAA 660 ATGCGTAGAG ATGTGGAGGA ACACCAGTGG CGAAGGCGAC TCTCTGGTCT GTAACTGACG 720 CTGAGGAGCG AAAGCGTGG GAGCGAACAG GATTAGATAC CCTGGTAGTC CACGCCGTAA 780 ACGATGAGTG CTAAGTGTTA GGGGGTTTCC GCCCCTTAGT GCTGCAGCTA ACGCATTAAG 840 CACTCCGCCT GGGGAGTACG GTCGCAAGAC TGAAACTCAA AGGAATTGAC GGGGGCCCGC 900 ACAAGCGGTG GAGCATGTGG TTTAATTCGA AGCAACGCGA AGAACCTTAC CAGGTCTTGA 960 CATCCTCTGA ACATCCTAGA GATAGGACGT CCCCTTCGGG GCAAAATGAC AGGTGGTGCA1020 TGGTTGCC 1028

[0050] rpoB: TTCCGCGCGA GCTATGCTCG CATTAGCGAA GTGTTAGAAT TACCAAATCT CATTGAAATT CAAACCTCTT CTTATCAGTG GTTTCTTGAT GAGGGTCTTA GAGAGATGTT TCAAGACATA 120 TCACCAATTG AGGATTTCAC TGGTAACCTC TCTCTTGAGT TCATTGATTA TAGTTTAGGT 180 240. GAGCCTAAAT ATCCTGTAGA GGAATCAAAA GAACGTGATG TGACTTACTC AGCTCCGCTA AGAGTGAAGG TTCGTTTAAT TAACAAAGAA ACTGGAGAGG TAAAAGACCA AGATGTCTTC ATGGGTGATT TCCCTATTAT GACAGATACA GGTACTTTTA TCATTAACGG TGCGGAACGT 360 GTTATTGTTT CCCAGCTGT TCGGTCTCCA AGTGTATATT TCAGTGGTAA OWNER 420 AACGGTAAAA AAGGTTTTAC CGCAACTGTC ATTCCAAACC GTGGCGCATG GTTAGAATAC 480 GAAACTGATG CGAAAGATGT TGTTTATGTC CGCATTGATC GCACACGTAA GTTGCCGGTT 540 ACGGTTCTTT TGCGTGCTCT CGGCTTCGGC TCCGATCAAG AGATTCTTGA TCTCATAGGA 600 660. ACCTGCGAAA TACGCTTGAT AAAGATAACA CAGAAAACAG TGACAAAGCG TTGCTGGAAA TTTACGAGCG TCTCCGTCCT GGAGAGCCGC CTACAGTAGA AAATGCGAAA 720 AGCTTGCTTG ATTCTCGTTT CTTTGATCCG AACGATCGAT GCCC 764

[0051] gyrB: ATGGAACAGC AGCAAAACAG TTATGATGAA AATCAGATAC AGGTACTAGA AGGATTGGAA 60 GCTGTTCGTA AAAGACCGGG GATGTATATC GGTTCGACAA ACAGCAAAGG CCTTCACCAC 120 CTGGTATGGG AAATTGTCGA CAATAGTATT GACGAAGCCC TCGCCGGTTA TTGTACGGAT 180 ATCAATATCC AAATCGAAAA AGACAACAGT ATCACGGTTG TAGATAATGG CCGCGGTATT 240 CCAGTCGGTA TTCATGAAAA AATGGGCCGT CCTGCGGTAG AAGTCATTAT GACGGTACTT 300 CATGCCGGAG GAAAATTTGA CGGAAGCGGC TATAAAGTAT CCGGAGGATT ACACGGTGTA 360 GGTGCGTCTG TCGTAAACGC ACTATCAACA GAGCTTGATG TGACGGTTCA CCGTGACGGT 420 AAAATTCACC GCCAAACTTA TAAACGCGGA GTTCCGGTTA CAGACCTTGA AATCATTGGC 480 GAAACGGATC ATACAGGAAC GACGACACAT TTTGTCCCGG ACCCTGAAAT TTTCTCAGAA 540 ACAACCGAGT ATGATTATGA TCTGCTTGCC AACCGCGTAC GTGAATTAGC CTTTTTAACA 600 AAGGGCGTAA ACATCACGAT TGAGGATAAA CGTGAAGGAC AAGAGCGCAA AAATGAATAC 660 CATTACGAAG GCGGAATTAA AAGTTATGTA GAGTATTTAA ACCGCTCTAA AGAGGTTGTC 720 CATGAAGAGC CGATTTACAT TGAAGGCGAA AAGGACGGCA TTACGGTTGA AGTGGCTTTG 780 CAATACAATG ACAGCTACAC AAGCAACATT TACTCGTTTA CAAACAACAT TAACACGTAC 840 GAAGGCGGTA CCCATGAAGC TGGCTTCAAA ACGGGCCTGA CTCGTGTTAT CAACGATTAC 900 GCCAGAAAAA AAGGGCTTAT TAAAGAAAAT GATCCAAACC TAAGCGGAGA TGACGTAAGG 960 GAAGGGCTGA CAGCGATTAT TTCAATCAAA CACCCTGATC CGCAGTTTGA GGGCCAAACG1020 AAAACAAAGC TGGGCAACTC AGAAGCACGG ACGATCACCG ATACGTTATT TTCTACGGCG1080 ATGGAAACAT TTATGCTGGA AAATCCAAGAT GCAGCCAAAA AAATTGTCGA TAAAGGCTTA1140 ATGGCGGCAA GAGCAAGAAT GGCTGCGAAA AAAGCCCGTG AACTAACACG TCGTAAGAGT1200 GCTTTGGAAA TTTCAAACCT GCCCGGTAAG TTAGCGGACT GCTCTTCAAA AGATCCGAGC1260 ATCTCCGAGT TATATATCGT AGAGGGTGAC TCTGCCGGAG GATCTGCTAA ACAAGGACGC1320 GACAGACATT TCCAAGCCAT TTTGCCGCTT AGAGGTAAAA TCCTAAACGT TGAAAAGGCC1380 AGACTGGATA AAATCCTTTC TAACAACGAA GTTCGCTCTA TGATCACAGC GCTCGGCACA1440 GGTATTGGGG AAGACTTCAA CCTTGAGAAA GCCCGTTACC ACAAAGTTGT CATTATGACA1500 GATGCCGATG TTGACGGCGC GCACATCAGA ACACTGCTGT TAACGTTCTT TTACAGATAT1560 ATGCGCCAAA TTATCGAGAA TGGCTACGTG TACATTGCGC AGCCGCCGCT CTACAAGGTT1620 CAACAGGGGA AACGCGTTGA ATATGCGTAC AATGACAAGG AGCTTGAAGA GCTGTTAAAA1680 ACTCTTCCTC AAACCCCTAA GCCTGGACTG CAGCGTTACA AAGGTCTTGG TGAAATGAAT1740 GCCACCCAGC TATGGGAGAC AACCATGGAT CCTAGCTCCA GAACACTTCT TCAGGTAACT1800 CTTGAAGATG CAATGGATGC GGACGAGACT TTTGAAATGC TTATGGGCGA CAAGGTAGAA1860 CCGCGCCGAA ACTTCATAGA AGCGAATGCG AGATACGTTA AAAATCTTGA CATCTAA 1917。

Claims

1. A microbial agent for controlling whiteflies, characterized in that: The microbial agent is a Bacillus subtilis MJ-4 fermentation broth obtained by seed activation and fermentation.

2. A microbial agent for controlling whiteflies, characterized in that: The microbial agent is prepared from the fermentation broth of Bacillus subtilis MJ-4 and is in the form of a wettable powder or suspension.

3. The microbial agent for controlling whiteflies according to claim 1 or 2, characterized in that: Bacillus subtilis MJ-4 was isolated from the diseased coleopteran bark beetle and obtained through screening, culture, morphological characteristics, and physiological and biochemical assays.

4. The microbial agent for controlling whiteflies according to claim 1 or 2, characterized in that: The effective viable count in the microbial agent is 5 × 10⁻⁶. 8 CFU / mL ~ 1×10 11 CFU / mL.

5. The microbial agent for controlling whiteflies according to claim 1, 2, or 4, characterized in that: The microbial inoculant also includes an active agent, which is 1‰ to 4‰ Tween-20.

6. The application of the microbial agent according to any one of claims 1 to 5 in products for controlling whiteflies.

7. The application of the microbial agent according to claim 5 in products for controlling whiteflies, characterized in that: Microbial agents can exhibit repellent, contact, and stomach poison insecticidal activities against all stages of the whitefly.

8. The method of using the microbial inoculant according to any one of claims 1 to 7, characterized in that: The microbial agent was evenly sprayed onto the upper and lower surfaces of the leaves of crops infested with whiteflies until they were moist. The whiteflies died quickly, and for a certain period of time after the microbial agent was applied, the crop leaves were no longer infested with whiteflies.

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