A comprehensive prevention and control method for oilseed rape diseases and insect pests suitable for aerial prevention

Abstract

This invention relates to the field of agricultural plant protection technology, specifically to an integrated pest management method for rapeseed suitable for aerial application, comprising the following steps: mixing Bacillus amyloliquefaciens Bam22 with imidacloprid and cyazofamid for aerial application; wherein, the Bacillus amyloliquefaciens Bam22 bacterial solution is diluted to a concentration of (2.5-5.0) × 10⁻⁶. 7 The dosage of cfu / mL was reduced to (6-9) g / mu for imidacloprid and (18-26) g / mu for boscalid. This invention achieves a synergistic effect by combining the pathogen-inhibiting effect of the Bam22 strain with the targeted control function of chemical agents. This significantly reduces the concentration of chemical agents and avoids pesticide damage from aerial spraying while ensuring that the efficacy of pest and disease control is not reduced. At the same time, the growth-promoting function of the Bam22 strain is used to restore the growth status of rapeseed, enhance the plant's stress resistance, and further ensure the yield and quality of rapeseed.

Description

Technical Field

[0001] This invention relates to the field of agricultural plant protection technology, specifically to an integrated pest management method for rapeseed diseases and pests suitable for aerial spraying. Background Technology

[0002] Rapeseed, as a globally important oilseed crop, directly impacts oilseed supply security and agricultural economic benefits through its yield and quality. During rapeseed cultivation, frequent pests and diseases are key factors restricting yield increases. Aphids damage the vascular bundles of leaves and block nutrient transport through their piercing-sucking mouthparts, while sclerotinia rot causes plant decay and wilting. Together, these two pests can reduce rapeseed yield by 15%-30%, with severely affected areas experiencing yield reductions exceeding 50%. Therefore, pest and disease control is a core aspect of rapeseed production.

[0003] With the development of agricultural mechanization and intelligentization, drone-based pest control has become the mainstream method for large-scale rapeseed cultivation due to its advantages such as high operational efficiency, wide coverage, and low labor costs. In existing technologies, imidacloprid as an insecticide, boscalid as a fungicide, and Bacillus amyloliquefaciens as a biocontrol agent have been publicly reported for their individual applications and some combination schemes. However, none of these technologies have been adapted to the technical characteristics of aerial spraying operations, resulting in two major pain points in rapeseed aerial pest control: 1. Aerial spraying relies on high concentrations of chemical agents to ensure efficacy, but rapeseed leaves are sensitive and high concentrations of agents can easily cause phytotoxicity, and droplet drift can cause environmental pollution; if the concentration of chemical agents is simply reduced, the efficacy will be greatly reduced and the control needs cannot be met.

[0004] 2. Conventional pesticide mixing schemes do not take into account the fluid characteristics of aerial spraying. After mixing, the viscosity and surface tension of the pesticide are not compatible with the drone atomization system, resulting in uneven droplet size and problems such as "pesticide damage in oversprayed areas and insufficient control in missed sprayed areas". Summary of the Invention

[0005] To address the aforementioned shortcomings in existing technologies, the present invention aims to provide an integrated pest management method for rapeseed using aerial spraying. Through a synergistic design involving reduced chemical pesticide use, controlled fluid properties, and matched aerial spraying parameters, the technical bottleneck of "inability to simultaneously address pesticide damage and control efficacy" in existing rapeseed aerial spraying techniques is resolved.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: A method for integrated pest management of rapeseed diseases and pests suitable for aerial spraying is provided, which includes the following steps: Bacillus amyloliquefaciens Bam22 was mixed with imidacloprid and cyazofamid for aerial application; the Bacillus amyloliquefaciens Bam22 bacterial solution was diluted to a concentration of (2.5-5.0) × 10⁻⁶. 7cfu / mL, the dosage of imidacloprid and cefazolin was reduced to (6-9) g / mu and (18-26) g / mu, respectively.

[0007] Preferably, the Bacillus amyloliquefaciens Bam22 has the accession number CGMCC No. 11329.

[0008] It should be noted that Bacillus amyloliquefaciens Bam22 is a publicly disclosed deposit (CN105219679A, a highly efficient biocontrol strain of Bacillus amyloliquefaciens Bam22 for clubroot disease in cruciferous plants).

[0009] Preferably, the bacterial suspension of Bacillus amyloliquefaciens Bam22 is diluted to a concentration of 2.5 × 10⁻⁶. 7 cfu / mL.

[0010] Preferably, the dosages of imidacloprid and cyazofamid are reduced to 9 g / mu and 24 g / mu, respectively.

[0011] Preferably, the rapeseed pests and diseases are aphids and rapeseed sclerotinia stem rot.

[0012] The beneficial effects of this invention are as follows: 1. By combining the pathogen-inhibiting effect of the Bam22 strain with the targeted control function of chemical agents, a synergistic effect is achieved, which significantly reduces the concentration of chemical agents and avoids pesticide damage from aerial spraying while ensuring that the efficacy of pest and disease control is not reduced. At the same time, by leveraging the growth-promoting function of the Bam22 strain, the growth status of rapeseed is restored, the plant's resistance to stress is enhanced, and the yield and quality of rapeseed are further guaranteed.

[0013] 2. This invention optimizes the viscosity, surface tension, and other fluid parameters of the compound pesticide by adjusting the dilution ratio of the Bam22 bacterial solution (100-200 times), making it perfectly compatible with the spraying system of conventional agricultural drones. The optimized compound pesticide produces uniform droplet size (range 200-300μm) after atomization, avoiding drift loss of small-diameter droplets and solving the problem of uneven leaf adhesion of large-diameter droplets, thus achieving uniform distribution of the pesticide in the rapeseed canopy during aerial spraying. Attached Figure Description

[0014] Figure 1 A schematic diagram illustrating the compatibility of boscalid and imidacloprid with Bam22 strain; Figure 2 This diagram illustrates the inhibition of Sclerotinia sclerotiorum growth by cyazofamid and imidacloprid with strain Bam22. Detailed Implementation

[0015] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0016] Example I. Bacillus amyloliquefaciens Bam22 (CGMCC No. 11329) is compatible with both insecticides and fungicides. 1. Mix the recommended concentrations of pesticides for controlling sclerotinia stem rot and aphids in LB medium (40 g / mu of 50% boscalid water-dispersible granules diluted in 45 L / mu of water, equivalent to 888.9 mg / L; 15 g / mu of 10% imidacloprid wettable powder diluted in 45 L / mu of water, equivalent to 333.3 mg / L), and then dilute to 1×10⁻⁶ mg / L. 5 Bam22 (cfu / mL) was spread onto a culture medium, with sterile water as a control. The medium was incubated in the dark at 30°C for 24 hours, and colony growth was counted. Figure 1 It can be seen that cyprodinil and imidacloprid are compatible with the Bam22 strain.

[0017] 2. Inoculate the center of a PDA plate with *Sclerotinia sclerotinia*. Dip a 3mm diameter filter paper into a solution of the recommended concentration of pesticide for controlling sclerotinia stem rot and aphids in rapeseed (same as above, i.e., 40g / mu of 50% cyazofamid water-dispersible granules diluted in 45L / mu of water, equivalent to 888.9mg / L; 15g / mu of 10% imidacloprid wettable powder diluted in 45L / mu of water, equivalent to 333.3 mg / L) or a diluted solution of *Bacillus amyloliquefaciens* Bam22 (1×10⁻⁶) at the same concentration. 6 After (cfu / mL), place the filter paper 3 cm away from the *Sclerotinia sclerotiorum* mycelial block on a PDA plate, let it stand for 30 min, remove the filter paper, and place the petri dish in a 25℃ incubator. Incubate in the dark for 72 h, then observe the growth of *Sclerotinia sclerotiorum* and *Bacillus amyloliquefaciens*. Figure 2 It can be seen that Bam22 + imidacloprid + cyazofamid can more effectively inhibit the growth of Sclerotinia sclerotiorum.

[0018] II. Field Trial Materials 1. Rapeseed variety: Deyou No. 6 2. Biocontrol strain: Bacillus amyloliquefaciens Bam22, cultured for 48 hours to a bacterial concentration of 5.0 × 10⁻⁶. 9 The concentration of bacteria was 2.5 × 10⁻⁶ CFU / mL, diluted 200 times before use. 7 cfu / mL; 3. Chemical agents: 10% imidacloprid wettable powder, 50% boscalid water-dispersible granules; 4. Experimental crop: Brassica napus (mainly cultivated variety), and the experiment was conducted during the peak flowering period of rapeseed (a period of high incidence of aphids and sclerotinia stem rot). 5. Application equipment: Conventional agricultural multi-rotor drone, spraying during the rapeseed flowering period; operating parameters are: flight altitude 2m, flight speed 4m / s, pesticide solution volume per mu 2 L, and wind speed ≤2.5m / s in the operating environment; 6. Experimental grouping: Five treatment groups were set up, with three replicates per group. The plot area was 667㎡, and the groups were randomly assigned to blocks as follows: Blank control group (CK): Only an equal amount of clean water was sprayed; Traditional aerial spraying group (T1): Imidacloprid 15 g / mu + Cyclomethasone 40 g / mu (without Bam22 strain) + (Sodium nitrophenolate, surfactant, dispersant and other adjuvants); Low-concentration chemical agent group (T2): Imidacloprid reduced by 40% (9g / mu) + Cyclomethasone reduced by 40% (24g / mu) (without Bam22 strain); This invention group (T3): Bam22 bacterial suspension (2.5 × 10⁻⁶) 7 (cfu / mL) + Imidacloprid 9 g / mu + Cyclomethasone 24 g / mu.

[0019] Biological control group (T4): Bam22 bacterial suspension (2.5×10⁻⁶) 7 (cfu / mL).

[0020] III. Core Experimental Data Results (I) Investigation on the incidence and severity of phytotoxicity The extent of pesticide damage to rapeseed leaves was investigated 7 and 14 days after application. Damage severity was categorized into four levels: 0 (no damage), 1 (slight chlorosis), 2 (leaf curling), 3 (damage to the growing point), and 4 (wilting of the entire plant). The incidence of pesticide damage was calculated as (number of damaged plants / total number of plants) × 100%. The pesticide damage index was calculated as Σ(number of plants damaged at each level × level number) / (total number of plants × highest level number) × 100%. The results are as follows: Conclusion: The traditional aerial spraying group (T1) showed obvious phytotoxicity due to the high concentration of chemical agents applied; the group of the present invention (T3), the low concentration chemical agent group (T2), and the biological control group (T4) all showed no phytotoxicity symptoms, confirming that the present invention can control the agent concentration within the safe tolerance range of rapeseed and completely avoid the risk of phytotoxicity from aerial spraying.

[0021] (II) Survey on the effectiveness of pest and disease control 1. Aphid control efficacy: At 3, 7, and 14 days after application, a five-point sampling method was used, with the number of aphids on 20 rapeseed plants at each point. Control efficacy = (number of aphids in the control group - number of aphids in the treatment group) / number of aphids in the control group × 100%. 2. Sclerotinia stem rot control efficacy: The incidence of sclerotinia stem rot was investigated 21 days after application. The severity of the disease was divided into four levels: disease index = Σ(number of diseased plants at each level × level) / (total number of plants × highest level) × 100%. Control efficacy = (disease index of control group - disease index of treatment group) / disease index of control group × 100%. Conclusion: The control efficacy of the low-concentration chemical agent group (T2) and the biological control group (T4) decreased significantly and could not meet the control requirements. The control efficacy of the present invention group (T3) was not significantly different from that of the traditional high-concentration aerial spraying group (T1). The aphid control efficacy remained above 80% throughout the process, and the sclerotinia disease control efficacy reached 80.54%. This confirms that the Bam22 strain and the low-concentration chemical agent have a synergistic effect, which can completely make up for the control efficacy gap after the reduction of chemical agents.

[0022] (III) Testing the uniformity of aerial spraying The uniformity of droplet distribution was detected using the water-sensitive paper method. Water-sensitive paper was placed in the upper, middle, and lower layers of the rapeseed canopy, and the droplet density (droplets / cm²), droplet size (μm), and coefficient of variation (CV, the smaller the CV, the better the uniformity) were measured. The results are as follows: Conclusion: Due to the fluid characteristics regulation effect of Bam22 bacterial solution, the composite agent of this invention (T3) has higher droplet density and more uniform particle size. The distribution variation coefficient is reduced by 42.8% compared with the traditional aerial spraying group, which significantly improves the uniformity of aerial spraying and avoids the problems of "phytotoxicity in oversprayed areas and insufficient control in missed sprayed areas".

[0023] (iv) Indicators related to rapeseed plant growth promotion and yield The rapeseed plant height and number of effective siliques per plant were investigated 35 days after pesticide application. The thousand-grain weight and plot yield were measured after maturity. The results are as follows: Relative yield increase rate = (Treatment group yield - Control group yield) / Control group yield × 100% Conclusion: Due to the growth-promoting function of the Bam22 strain, the rapeseed plant height and number of effective pods in the T3 group of this invention were significantly improved, and the yield increased by 13.50% compared with the blank control group. In contrast, the yield of the traditional aerial spraying group decreased by 6.71% compared with the blank control group due to the damage caused by pesticides. This invention confirms that it can improve the quality and increase the yield of rapeseed while controlling pests and diseases.

[0024] In summary, this invention achieves four core effects through the optimized combination ratio of "Bacillus amyloliquefaciens Bam22 + low concentration imidacloprid + low concentration cyazofamid" and its adaptability to aerial spraying: 1. After reducing the amount of chemical agents by 40%, the incidence of phytotoxicity is 0, completely solving the phytotoxicity problem of traditional aerial spraying with high concentrations of pesticides; 2. With the synergistic effect of Bam22 strain and chemical agents, the aphid control efficacy is ≥82.6% and the sclerotinia disease control efficacy reaches 80.54%. The control efficacy is not significantly different from that of traditional high-concentration aerial spraying, meeting the needs of pest and disease control. 3. The compound agent optimizes the fluid characteristics of aerial spraying, improving droplet distribution uniformity by 42.8%, and is suitable for the characteristics of drone aerial spraying operations; 4. The growth-promoting function of the Bam22 strain effectively improved the agronomic traits and yield of rapeseed, increasing the yield by 13.50% compared with the blank control group, achieving the dual effect of "prevention and control + quality improvement".

[0025] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0026] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for integrated pest management of rapeseed diseases and pests suitable for aerial spraying, characterized in that, Includes the following steps: Bacillus amyloliquefaciens Bam22 was mixed with imidacloprid and cyazofamid for aerial application; the Bacillus amyloliquefaciens Bam22 bacterial solution was diluted to a concentration of (2.5-5.0) × 10⁻⁶. 7 cfu / mL, the dosage of imidacloprid and cefazolin was reduced to (6-9) g / mu and (18-26) g / mu, respectively.

2. The integrated pest management method for rapeseed diseases and pests suitable for aerial spraying according to claim 1, characterized in that, The preservation number of the Bacillus amyloliquefaciens Bam22 is CGMCC No. 11329.

3. The integrated pest management method for rapeseed diseases and pests suitable for aerial spraying according to claim 1, characterized in that, The bacterial suspension of Bacillus amyloliquefaciens Bam22 was diluted to a concentration of 2.5 × 10⁻⁶. 7 cfu / mL.

4. The integrated pest management method for rapeseed diseases and pests suitable for aerial spraying according to claim 1, characterized in that, The dosages of imidacloprid and cyazofamid were reduced to 9 g / mu and 24 g / mu, respectively.

5. The integrated pest management method for rapeseed diseases and pests suitable for aerial spraying according to claim 1, characterized in that, The rapeseed diseases and pests mentioned are aphids and rapeseed sclerotinia disease.

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