Metarhizium anisopliae jgmh-2401 and its application in scarab pest control
By combining Metarhizium anisopliae JGMH-2401 with straw return to the field, the problem of controlling beetle pests during the overwintering period was solved, achieving precise control during the feeding stage before overwintering, with good environmental friendliness and control effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHENYANG AGRI UNIV
- Filing Date
- 2026-03-26
- Publication Date
- 2026-06-02
AI Technical Summary
Existing technologies are insufficient to effectively control scarab beetle pests during the overwintering period, especially since the spores of Metarhizium anisopliae germinate slowly under low-temperature conditions and are difficult to colonize in high-cellulose environments, making precise control difficult.
The application method of combining Metarhizium anisopliae JGMH-2401 with straw return to the field was adopted. By allowing the larvae of the scarab beetle to come into contact with and become infected by the strain during their feeding activity before overwintering, a high-content spore powder was prepared by solid-state fermentation of sorghum grains and directly applied to crop straw to achieve precise control.
By successfully shifting the control window to the feeding stage before overwintering, effective control of scarab beetle larvae was achieved, reducing the frequency of chemical pesticide use and environmental pollution, and scarab beetle pests are less likely to develop resistance.
Smart Images
Figure CN122128109A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of microbial technology, and in particular to Metarhizium anisopliae JGMH-2401 and its application in the control of scarab beetle pests. Background Technology
[0002] Scarab beetles belong to the superfamily Scarabaeidae in the order Coleoptera. Their larvae (grubs) inhabit the soil and feed on crop roots, tubers, and seeds, while adults gnaw on leaves, flowers, and fruits, causing significant losses to agricultural production. Currently, the control of scarab beetles still mainly relies on chemical pesticide drenching and seed dressing agents. However, the soil-dwelling nature of grubs makes precise control difficult, especially against late-instar larvae or pupal stages that do not feed after overwintering. Seed dressing agents that rely on feeding for effectiveness are basically ineffective, missing the critical control window. Therefore, there is an urgent need to develop a control technology that can be effective during the overwintering period.
[0003] Biological control has become an important development direction for the control of scarab beetles due to its advantages such as environmental friendliness, low likelihood of pest resistance, and safety against non-target organisms. Among these, *Metarhizium anisopliae* (a type of beetle fungus) is a key target. Metarhizium anisopliae As a broad-spectrum entomopathogenic fungus, Metarhizium anisopliae is characterized by its wide host range, strong pathogenicity, and ease of large-scale production, and has received widespread attention in the biological control of pests. Currently, while Metarhizium anisopliae is used in biological control, it faces two major bottlenecks: 1. Low activity at low temperatures: During overwintering, the soil temperature is low, and the spores of conventional strains germinate slowly, failing to complete effective infection in the early or during overwintering period; 2. Poor colonization in the field: In the high-cellulose environment of straw return to the field, the strains struggle to establish a stable spatial distribution and sustained effect.
[0004] Therefore, developing a strain of Metarhizium anisopliae that has both good insecticidal effect and strong environmental adaptability in the control of overwintering pests, and matching it with corresponding application techniques, is of great significance for promoting the industrialization of green control of grubs. Summary of the Invention
[0005] The purpose of this invention is to provide a Metarhizium anisopliae JGMH-2401 for scarab beetles and its application in the control of scarab beetle pests. By combining the application of Metarhizium anisopliae JGMH-2401 inoculum with straw return to the field, scarab beetle larvae that are feeding before overwintering come into contact with and become infected by the fungus while feeding on contaminated straw. This successfully shifts the control window forward to the feeding stage of scarab beetle larvae before overwintering, achieving an effective overwintering control effect.
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a strain of Metarhizium anisopliae JGMH-2401, classified as Metarhizium anisopliae. Metarhizium anisopliaeIt was deposited on March 3, 2026, at the China General Microbiological Culture Collection Center, Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC NO:42519.
[0007] This invention provides the application of the aforementioned Metarhizium anisopliae JGMH-2401 in the preparation of biocontrol agents.
[0008] This invention provides a biological control powder containing the aforementioned Metarhizium anisopliae JGMH-2401, wherein the spore content of Metarhizium anisopliae JGMH-2401 is (8.0-8.5) × 10⁻⁶. 9 pcs / gram.
[0009] The present invention also provides a method for preparing the biocontrol powder, comprising the following steps: The product was prepared by using sorghum grains as a solid fermentation substrate, inoculating them with Metarhizium anisopliae JGMH-2401 for 8-12 days of fermentation, followed by freeze-drying and grinding.
[0010] The present invention also provides the application of the aforementioned Metarhizium anisopliae JGMH-2401 or the aforementioned biological control powder in the control of scarab beetle pests.
[0011] Preferably, the beetle pests include the cotton beetle, the white-spotted beetle, and the large black-gill beetle.
[0012] The present invention also provides a method for controlling scarab beetle pests, comprising the following steps: applying the biological control powder or a suspension of the biological control powder directly to crop straw returned to the field before the overwintering period of scarab beetle larvae.
[0013] Preferably, when applying the biological control powder, the application rate is 1.23-2.46 kg / mu; when applying the suspension of the biological control powder, the application rate is 100-200 L / mu.
[0014] Preferably, the spore concentration of the suspension of the biocontrol powder is (0.1-1000)×10⁻⁶. 5 per mL.
[0015] By adopting the above technical solution, the present invention has the following beneficial effects: 1. The technical solution of this invention combines the application of the inoculant of Metarhizium anisopliae JGMH-2401 with the straw return to the field. By taking advantage of the feeding habits of grubs before overwintering, the grub larvae that are feeding before overwintering come into contact with and become infected by the strain while feeding on the infected straw, thus causing them to become diseased. This successfully moves the control window forward to the feeding stage of the grub larvae before overwintering, and achieves precise application of the pesticide, effectively overcoming the problem of traditional methods failing during the overwintering period.
[0016] 2. As a biological control method, the technical solution described in this invention has a longer action cycle compared to chemical control, which can reduce the amount and frequency of pesticide application, reduce environmental pollution, and make it less likely for beetle pests to develop resistance, thus having broad prospects for agricultural application.
[0017] 3. The Metarhizium anisopliae JGMH-2401 inoculant described in this invention has a high spore content and exhibits good storage and application stability in overwintering control scenarios.
[0018] Biological Preservation Instructions
[0019] This invention relates to *Metarhizium anisopliae* JGMH-2401, classified as *Metarhizium anisopliae*. Metarhizium anisopliae It was deposited on March 3, 2026, at the China General Microbiological Culture Collection Center (CGMCC), Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC No. 42519. Attached Figure Description
[0020] Figure 1 Image of a dead cotton beetle larva before the *Metarhizium anisopliae* JGMH-2401 bacterium was isolated from *Metarhizium anisopliae* in Example 1; Figure 2 This is a colony morphology diagram of the strain isolated in Example 1. Figure 2 In the diagram, A represents the front colony morphology after 7 days of incubation, B represents the reverse colony morphology after 7 days of incubation, C represents the front colony morphology after 26 days of incubation, and D represents the reverse colony morphology after 26 days of incubation. Figure 3 The image shows the spore morphology of the strain isolated in Example 1. Figure 3 In this context, A represents the spore morphology, and B represents the sporophyte morphology. Figure 4 The phylogenetic tree constructed for Example 1; Figure 5 This is a diagram illustrating the development of white-spotted scarab beetle larvae infected with Metarhizium anisopliae JGMH-2401 as described in Example 2. Figure 5 In this context, A represents the initial stage of infection, B represents the middle stage of infection, and C represents the later stage of infection. Figure 6 The mortality rate of white-spotted flower scarab beetle larvae after soaking in different spore concentrations of Metarhizium anisopliae JGMH-2401 as described in Example 2; Figure 7 The spore powder of Metarhizium anisopliae JGMH-2401 prepared in Example 3; Figure 8 The images show the mortality of straw after soaking in different concentrations of Metarhizium anisopliae powder JGMH-2401 as described in Example 3. Detailed Implementation
[0021] This invention provides a strain of Metarhizium anisopliae JGMH-2401, classified as Metarhizium anisopliae. Metarhizium anisopliae It was deposited on March 3, 2026, at the China General Microbiological Culture Collection Center (CGMCC), Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC No. 42519.
[0022] This invention provides the application of the aforementioned Metarhizium anisopliae JGMH-2401 in the preparation of biocontrol agents.
[0023] The present invention provides a biological control powder containing the aforementioned Metarhizium anisopliae JGMH-2401.
[0024] In this invention, the spore content of the *Metarhizium anisopliae* JGMH-2401 is preferably (8.0-8.5) × 10⁻⁶. 9 The concentration of particles per gram is further preferably (8.1-8.2) × 10⁻⁶. 9 pcs / gram, with a further preferred value of 8.125 × 10⁻⁶. 9 pcs / gram.
[0025] The present invention also provides a method for preparing the biological control powder, comprising the following steps: using sorghum grains as a solid fermentation substrate, inoculating the *Metarhizium anisopliae* JGMH-2401 and fermenting for 8-12 days, followed by freeze-drying and grinding to obtain the powder.
[0026] In this invention, the fermentation temperature is preferably 25-30℃, more preferably 26-29℃, and even more preferably 28℃.
[0027] In this invention, the freeze-drying time is preferably 24h-96h, more preferably 48h-84h, and even more preferably 72h; the freeze-drying temperature is preferably -20℃.
[0028] In this invention, the grinding process is preferably followed by sieving, and then the undersize material is collected to obtain the biological control powder. In this invention, the mesh size of the sieve is preferably 50-300 mesh, more preferably 100-200 mesh, and even more preferably 200 mesh.
[0029] The present invention also provides the application of the aforementioned Metarhizium anisopliae JGMH-2401 or the aforementioned biological control powder in the control of scarab beetle pests.
[0030] In this invention, the beetle pests include the cotton beetle, the white-spotted beetle, and the large black-gill beetle.
[0031] The present invention also provides a method for controlling scarab beetle pests, comprising the following steps: applying the biological control powder or a suspension of the biological control powder directly to crop straw returned to the field before the overwintering period of scarab beetle larvae.
[0032] In this invention, when the biological control powder is applied, the preferred application rate is 1-3 kg / mu, more preferably 1.23-2.46 kg / mu, and even more preferably 1.845 kg / mu; when the suspension of the biological control powder is applied, the preferred application rate is 10-1000 L / mu, more preferably 100-200 L / mu, and even more preferably 150 L / mu.
[0033] In this invention, the spore concentration of the suspension of the biocontrol powder is preferably (1-2000)×10⁻⁶. 5 Cells / mL, more preferably (10-1500)×10 5 Cells / mL, more preferably 1×10 8 per mL.
[0034] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0035] Example 1: Isolation and Identification of Metarhizium anisopliae JGMH-2401
[0036] (I) Isolation and purification of Metarhizium anisopliae JGMH-2401
[0037] Cotton-necked beetles were collected in Wafangdian, Dalian, and reared in a laboratory. Then, the carcasses of contaminated cotton-necked beetle larvae (such as...) were selected. Figure 1 The spores were scraped from the surface of the bacteria and inoculated onto PDA agar plates, then incubated in the dark at 28°C. After colonies grew, colonies free from contamination were selected and repeatedly transferred to new PDA agar plates for purification until a pure culture with consistent colony morphology was obtained, thus yielding strain 1.
[0038] (II) Identification of Metarhizium anisopliae JGMH-2401
[0039] 1. Morphological identification
[0040] Observed and measured using an optical microscope.
[0041] Strain 1 was cultured on PDA plates at 28°C. Initially, the colonies were white, gradually forming a ring-shaped dark green conidial layer with prolonged culture. Microscopic examination revealed colorless, septate, and smooth hyphae, 2.2-3.2 μm wide. Conidiophores could be solitary or branched, each apical bearing 2-5 columnar conidiophore cells (5.2-9.0) μm × (2.5-3.2) μm, producing conidial chains in a basotropic manner. Conidia were colorless, columnar, with blunt ends, measuring (4.5-6.8) μm × (1.8-2.9) μm. These morphological characteristics are consistent with *Metarhizium anisopliae* (a type of beetle). Metarhizium anisopliae Typical descriptions of ), such as Figure 2 and 3 .
[0042] 2. Molecular biological identification
[0043] After 6 days of single-spore isolation, purification, and culture, mycelia were scraped off in a clean bench, ground into fine powder with liquid nitrogen, and the total DNA of the strain was extracted using the Tiangen novel plant genomic DNA extraction kit.
[0044] Using extracted DNA as a template, PCR amplification was performed using the universal fungal primers ITS1 and ITS4. The PCR products were detected by 1.2% agarose gel electrophoresis, and the target band was recovered, purified, and then sequenced. The obtained sequences were BLAST aligned using NCBI, and a phylogenetic tree was constructed using the Neighbor-Joining method with MEGA12 software. Genetic distances were calculated using the P-distance model, and the reliability was assessed using the Bootstrap test.
[0045] The primer ITS1 sequence is shown in SEQ ID NO.1, specifically 5'-TCCGTAGGTGAACCTGCGC-3'; the primer ITS4 sequence is shown in SEQ ID NO.2, specifically 5'-TCCTCCGCTTATTGATATGC-3'.
[0046] Table 1 PCR reaction system
[0047] The PCR program is as follows: pre-denaturation: 94℃, 4 min; followed by 30 cycles, each cycle including denaturation at 94℃ for 30 s, annealing at 56℃ for 30 s, extension at 72℃ for 1 min; and extension at 72℃ for 5 min, followed by storage at 4℃.
[0048] The sequencing results of strain 1 are shown in SEQ ID NO.3, with a length of 564 bp and the specific sequence is as follows:
[0049] Phylogenetic trees were constructed using ITS base sequences, such as Figure 4 It can be seen that strain 1 is closely related to the genus *Metarhizium*, indicating that strain 1 has certain similarities with *Metarhizium anisopliae*. In summary, based on morphological characteristics and the similarity of the base sequence, strain 1 is presumed to be *Metarhizium anisopliae*, and is named *Metarhizium anisopliae* JGMH-2401.
[0050] Example 2: Determination of the indoor insecticidal activity of Metarhizium anisopliae JGMH-2401 for scarab beetles
[0051] (I) Determination of the indoor insecticidal activity of Metarhizium anisopliae JGMH-2401 on scarab beetles
[0052] 1. Preparation of spore suspension of Metarhizium anisopliae JGMH-2401
[0053] The *Metarhizium anisopliae* strain JGMH-2401 was inoculated onto PDA plates (PDA medium: 200g peeled potato, 1L distilled water, 15g agar, and 15g glucose; sterilized at 121℃ for 30 min by moist heat) and incubated in the dark at 28℃ for 7-10 days until abundant conidia were produced. Conidia were scraped from the plate using a sterile pipette tip and placed in sterile water containing 0.1% Tween-80. The plates were vortexed to ensure thorough dispersion, and the spore concentration was adjusted to 1.0 × 10⁻⁶ using a hemocytometer. 9 The spore density is calculated as spores / mL, which yields the spore suspension stock solution. This stock solution can be further diluted to the desired concentration (e.g., 1×10⁻⁶). 5 spores / mL, 1×10 6 spores / mL, 1×10 7 spores / mL, 1×10 8 Use (spores / mL).
[0054] 2. Indoor insecticidal activity assay against white-spotted flower beetle larvae (immersion method): The tested pests were healthy, uniformly sized first-instar larvae of the white-spotted flower beetle, raised in the laboratory. Spore suspension treatment groups were set up (concentrations of 1×10⁻⁶). 5 1×10 6 1×10 7 1×10 8 1×10 9 Ten larvae were included in each of the following groups: a control group (containing spores / mL) and a control group (containing 0.1% Tween-80 in water), with three replicates per group. Larvae were immersed in their respective suspensions for 2 minutes (heads were left intact), then removed and dried with sterile filter paper to remove excess liquid. They were then reared at 26°C and 70% relative humidity. Larval mortality was observed and recorded every 10 days for a total of 60 days.
[0055] The results showed that in the early stage of larval infection, the larvae were stiff, with no pigment production on their surface, and exhibited slight vital signs but had stopped feeding and remained rigid. In the middle stage of infection, white spores gradually appeared on the larval surface. In the later stage of infection, some green spores mixed with a small amount of white mycelium appeared on the larval surface. Figure 5 The strain of this invention, at a spore concentration of 1×10⁻⁶, 5 At a concentration of [number] cells / mL, it exhibited extremely strong infectivity and virulence against the larvae of the white-spotted flower scarab beetle, with a cumulative mortality rate of 100% over 40 days, demonstrating that *Metarhizium anisopliae* JGMH-2401 possesses insecticidal activity. Mortality is shown in Table 2. The results are as follows: Figure 6 .
[0056] Table 2 Mortality rate of white-spotted scarab beetle larvae after treatment with different concentrations of spore suspension of Metarhizium anisopliae JGMH-2401.
[0057] Example 3: Outdoor insecticidal experiment combining Metarhizium anisopliae JGMH-2401 with straw return to the field.
[0058] (I) Preparation of Metarhizium anisopliae spore powder JGMH-2401
[0059] Select whole, mold-free sorghum grains and rinse them three times with clean water to remove surface dust and impurities. After draining, completely submerge the sorghum grains in deionized water and soak them at room temperature for 12 hours. Then boil the sorghum grains for 30 minutes and drain excess water. Divide the boiled sorghum grains into 500mL incubation flasks, filling them to half their volume. Sterilize using an autoclave at 121℃ for 30 minutes. After sterilization, place the flasks in a clean bench to cool to room temperature and sterilize with a UV lamp for 30 minutes to further eliminate possible microbial contamination. Inoculate the *Metarhizium anisopliae* strain JGMH-2401 onto PDA agar plates. Once the plates are fully colonized, take 1 / 4 of a 9cm diameter mycelium block from the PDA agar and inoculate it into the incubation flasks using sterile forceps. Gently shake the containers to ensure the mycelium block is in full contact with the sorghum grains. Incubate in a 28℃ incubator in the dark. During cultivation, the container should be gently shaken every 3 days to ensure uniform mycelial growth. After 10 days of continuous cultivation, the sorghum grains covered with mycelium and spores are pre-frozen in an ultra-low temperature freezer at -80℃ for 2 hours, and then thoroughly dried in a vacuum freeze dryer. The dried product is then pulverized using a grinder and passed through a 200-mesh standard sieve to obtain the *Metarhizium anisopliae* JGMH-2401 spore powder. Hemocytometer analysis showed that the spore content of this powder was 8.125 × 10⁻⁶. 9 Units / gram, product such as Figure 7 As shown.
[0060] (II) Insecticidal activity determination against overwintering larvae of the large black-breasted scarab beetle under simulated straw return conditions
[0061] Third-instar larvae (overwintering larvae) of the large black-breasted scarab beetle, fed with standard laboratory feed and of uniform size, were selected as the test pests. The spore powder prepared above was diluted with sterile water containing 0.1% Tween-80 to form a spore suspension, and a 1×10⁻⁶ spore suspension was prepared. 4 1×10 5 1×10 6 1×10 7 1×10 8Five concentration gradients of spores / mL were used. A 20 mg / L thiamethoxam treatment served as the control group, and sterile water containing 0.1% Tween-80 served as the blank group. Equal amounts of corn stalk segments (approximately 300 g per concentration group, 10 groups, approximately 10 g per group, 3 replicates) were soaked for 10 min in different concentrations of spore suspension (approximately 812.5 mL per concentration group), as well as in the control and blank group solutions. After soaking, the stalks were drained until no dripping water remained. The soaked stalk segments were then placed in individual small rearing boxes, each containing an equal amount of stalks, and soil was added. One test larva was then introduced into the soil of each box. Ten larvae were treated at each concentration, and each treatment group was replicated three times.
[0062] Dig 50cm deep pits in the field and arrange rearing boxes at the bottom. Seal the gaps between the boxes and between the boxes and the pit walls with soil from the original field. This arrangement aims to simulate the natural habitat of larvae burrowing into the soil to overwinter after the autumn harvest and straw return to the field, making it close to the natural temperature and humidity conditions in the field. Record the number of surviving larvae every 10 days. Under outdoor conditions, spore germination and infection processes may be limited due to uncontrollable temperature and humidity.
[0063] To accurately assess the final lethal effect of the fungicide, the criteria for determining mortality are: the larvae completely lose their vital signs (such as no response to mechanical stimulation) or the insect body has been decomposed by soil microorganisms, and the cumulative mortality rate at each time point is recorded.
[0064] Table 3 Mortality rates of overwintering black-breasted scarab beetle larvae after consuming straw soaked in different concentrations of Metarhizium anisopliae powder diluted with JGMH-2401.
[0065] The results showed that, compared with the control group, the concentration of 1×10 8 Straw treated with a spore / mL inoculant dilution showed poor immediate efficacy. Mortality rates at 10 and 20 days post-treatment were significantly different from the control group (20 mg / L thiamethoxam). However, from 30 to 60 days post-treatment, the mortality rates were not significantly different from the control group (20 mg / L thiamethoxam), indicating an effect comparable to thiamethoxam. Compared to the blank control, a concentration of 1×10⁻⁶ was used. 8 Straw treated with a spore / mL inoculum solution resulted in mortality within 10 days post-treatment, with a mortality rate of 23.33%. The mortality rate increased continuously with prolonged treatment time, reaching a peak of 90% at 40 days (see Table 3 for specific data). Figure 8 In complex outdoor temperature and humidity conditions, strain JGMH-2401 showed a cumulative mortality rate of 90% against third-instar overwintering larvae of the large black-breasted scarab beetle after 40 days.
[0066] In summary, the technical solution described in this invention not only demonstrates that the *Metarhizium anisopliae* JGMH-2401 exhibits high pathogenicity but also excellent low-temperature tolerance and persistent effectiveness in the field. Furthermore, by combining the application of *Metarhizium anisopliae* JGMH-2401 with straw return to the field, this invention allows scarab beetle larvae to come into contact with and become infected with the strain while feeding on contaminated straw before overwintering. This successfully shifts the control window forward to the feeding stage before overwintering, effectively solving the bottleneck problem of traditional methods being ineffective during the overwintering process and effectively achieving overwintering control of scarab beetle larvae.
[0067] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A type of Metarhizium anisopliae JGMH-2401, characterized in that, The fungus, classified as *Metarhizium anisopliae*, was deposited on March 3, 2026, at the China General Microbiological Culture Collection Center (CGMCC), Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCCNO: 42519.
2. The application of the Metarhizium anisopliae JGMH-2401 as described in claim 1 in the preparation of biological control agents.
3. A biological control powder comprising *Metarhizium anisopliae* JGMH-2401 as described in claim 1, characterized in that, The spore content of the *Metarhizium anisopliae* JGMH-2401 was (8.0-8.5) × 10⁻⁶. 9 pcs / gram.
4. The method for preparing the biological control powder according to claim 3, characterized in that, Includes the following steps: The product is prepared by using sorghum grains as a solid fermentation substrate, inoculating them with the Metarhizium anisopliae JGMH-2401 as described in claim 1, fermenting for 8-12 days, and then freeze-drying and grinding.
5. The application of the Metarhizium anisopliae JGMH-2401 of claim 1 or the biological control powder of claim 3 in the control of scarab beetles.
6. The application according to claim 5, characterized in that, The beetle pests mentioned include the cotton beetle, the white-spotted beetle, and the large black-gill beetle.
7. A method for controlling scarab beetle pests, characterized in that, Includes the following steps: Before the overwintering period of scarab beetle larvae, the biological control powder of claim 3 or a suspension of the biological control powder of claim 3 is applied directly to the crop straw returned to the field.
8. The prevention and control method according to claim 7, characterized in that, When applying the biological control powder, the application rate is 1.23-2.46 kg / mu; When applying the suspension of the biological control powder, the application rate is 100-200 L / mu.
9. The prevention and control method according to claim 7, characterized in that, The spore concentration of the suspension of the biocontrol powder is (0.1-1000)×10 5 per mL.