Method for degrading benzamide insecticides on mulberry leaves

Abstract

The invention discloses a method for degrading benzamide insecticides on mulberry leaves. Benzamide insecticides pollute mulberry leaves to cause silkworm poisoning, and safety production of the sericulture is seriously affected, so that the degradation period of the benzamide insecticides on the mulberry leaves is shortened to 6-8 hours and is shortened by 80% or above compared with an existing microbial scheme by adopting a benzamide insecticide degradation composite microbial inoculant and combining carbonized silkworm manure and a pulsed magnetic field, and the method has the advantages that the method is simple, and the cost is low. The degradation rate is stabilized to be 95% or above, the treated mulberry leaves can be used for breeding silkworms, and the method has the advantages of being easy and convenient to operate and high in efficiency and is suitable for application and popularization in silkworm areas.

Description

TECHNICAL FIELD

[0001] The application belongs to silkworm breeding technology, and relates to a mulberry leaf treatment method, in particular to a method for efficiently degrading benzamide insecticides on mulberry leaves. BACKGROUND

[0002] Benzamide insecticides include chlorantraniliprole, chlorantraniliprole, etc. By activating the fish niding receptor of pests, it causes excessive release of calcium ions in cells, leading to continuous muscle contraction until death. Benzamide insecticides are widely used in agricultural and forestry production for pest control due to their high efficiency on lepidoptera pests, but the stable structure formed by the benzene ring and the amide bond leads to a long residual period (up to 14-21 days). Due to the air diffusion caused by unmanned aerial vehicle spraying, the mulberry field is polluted, which directly leads to the poisoning of silkworms and affects the yield and quality of cocoon, which has become the main reason affecting the safe production of mulberry at the present stage. The existing mulberry leaf benzamide insecticide degradation scheme mainly depends on high-temperature direct degradation or expensive enzyme preparations, and has problems of long degradation period, damaged mulberry leaf quality, high cost, etc. SUMMARY

[0003] Benzamide insecticide pollution of mulberry leaves leads to poisoning of silkworms, which has seriously affected the safe production of sericulture. The application adopts a composite microbial agent combined with carbonized silkworm manure, and after the action of a pulsed magnetic field, the degradation period of benzamide insecticides on mulberry leaves is 6-8 hours, which is more than 80% shorter than that of the existing microbial scheme, and the degradation rate is stably above 95%. The treated mulberry leaves can be used to feed silkworms, and have the advantages of simple operation, high efficiency, and are suitable for popularization and application in the silkworm area.

[0004] The application adopts the following technical scheme.

[0005] A method for degrading benzamide insecticides on mulberry leaves comprises the following steps: adding carbonized silkworm manure and a composite bacteria to weak alkaline water containing mulberry leaves, and then applying a pulsed magnetic field for 15-30 minutes; then turning off the pulsed magnetic field and standing for 6-8 hours to complete the degradation of benzamide insecticides on the mulberry leaves.

[0006] In the application, the silkworm manure is carbonized under anaerobic conditions to obtain carbonized silkworm manure; specifically, the silkworm manure is carbonized under anaerobic conditions at 500 DEG C for 2 hours to obtain carbonized silkworm manure.

[0007] In the application, the composite bacteria include rhodococcus and acid-producing klebsiella, which can degrade benzene rings and break amide bonds; as common knowledge, the composite bacteria are added to weak alkaline water in the form of bacterial liquid.

[0008] In the application, the pH of the weak alkaline water is 7.5-8.0; in the application, baking soda is used to adjust the pH of the water to 7.5-8.0, and then the mulberry leaves are added; preferably, the use amount ratio of the mulberry leaves to water is 1 kg: 1.5 L.

[0009] In the present application, the voltage of the pulse magnetic field is 12V, and the pulse frequency is 5Hz.

[0010] In the present application, after the standing is completed, the mulberry leaves are filtered and then cleaned to obtain the mulberry leaves in which the benzamide insecticide is degraded.

[0011] The application discloses application of the method for degrading benzamide insecticide on mulberry leaves in degrading benzamide insecticide on mulberry leaves.

[0012] The application discloses the mulberry leaves in which the benzamide insecticide is degraded, which are prepared by the method for degrading benzamide insecticide on mulberry leaves.

[0013] In the present application, the original mulberry leaves (before the weak alkaline water is added) contain benzamide insecticide; preferably, the benzamide insecticide includes bromocyclam, chlorbenzamide and the like.

[0014] The application discloses a method for feeding silkworms, which comprises the following steps: adding carbonized silkworm manure and compound bacteria into weak alkaline water containing mulberry leaves, then applying a pulse magnetic field for 15-30 minutes; then closing the pulse magnetic field, standing for 6-8 hours, filtering, cleaning the mulberry leaves again, to obtain mulberry leaves in which benzamide insecticide is degraded; and then feeding the silkworms with the mulberry leaves in which benzamide insecticide is degraded.

[0015] The application utilizes the combination of the bacterial flora, and the red ball and the acid-producing Klebsiella form a synergistic degradation path of "benzene ring opening-amide bond breaking"; further, the carbonized silkworm manure has the triple effects of adsorbing pesticides, fixing the bacterial flora and providing silicon elements to promote the repair of the mulberry leaves, and can also be reused for silkworm breeding waste; meanwhile, a low-energy physical strengthening, i.e. a pulse magnetic field device, is adopted to improve the degradation effect, without high temperature and high pressure, and the energy consumption is only 1 / 5 of that of ultrasonic waves. In summary, the application adopts the compound bacterial agent combined with the carbonized silkworm manure, and after the action of the pulse magnetic field, the degradation period of the benzamide insecticide on the mulberry leaves is 6-8 hours, which is shortened by more than 80% than the existing microbial scheme, the degradation rate is stably above 95%, and the treated mulberry leaves can be used to feed silkworms, and the application has the advantages of simple operation, high efficiency and the like, and is suitable for popularization and application in the silkworm area. DETAILED DESCRIPTION

[0016] The application carbonizes silkworm manure under anaerobic conditions to obtain carbonized silkworm manure; specifically, the silkworm manure of five-year-old silkworms is carbonized under anaerobic conditions at 500 DEG C for 2 hours to obtain the carbonized silkworm manure. The silkworm manure is an existing product, and the specific acquisition is a conventional technology, and can be obtained by filtering silkworm sand.

[0017] The carbonized silkworm manure and the compound bacteria are added into weak alkaline water containing mulberry leaves, then a pulse magnetic field is applied for 15-30 minutes; then the pulse magnetic field is closed, and the mixture is stood for 6-8 hours, then filtered, and the mulberry leaves are cleaned again to obtain mulberry leaves in which benzamide insecticide is degraded.

[0018] Conventionally, silkworms are fed mulberry leaves that have been degraded by benzamide insecticides.

[0019] The following specific experiments illustrate the technological advancements of this invention. The raw materials used are existing products, and the specific preparation operations and performance tests are conventional techniques.

[0020] A conventional copper coil is wound around the outside of an existing 200L open plastic bucket (the coil surrounds the bucket body) to serve as a pulse magnetic field device. The upper and lower coils are spaced 1cm apart, and the outer diameter of the copper wire is 3mm. The device uses a 12V DC power supply and copper coils. The cost is ≤50 yuan and it can be reused.

[0021] Rhodococcus sp. is a product of UTP Technology Suzhou Co., Ltd., and Klebsiella oxytoca is a product of Suzhou Baisco Biotechnology Co., Ltd. These products achieve the effect of opening the benzene ring structure of benzamide and breaking the amide bonds after ring opening. Combined with carbonized silkworm excrement, they can efficiently degrade benzamide insecticides under a pulsed magnetic field. Before use, they are added to beef extract peptone medium containing 0.05% chlorantraniliprole and cultured on a shaker at 30°C for 36 hours to obtain bacterial solutions (concentration ≥10). 8 (CFU / mL), take 20 mL of each when using.

[0022] Separate the silkworm excrement and take the excrement of the fifth instar silkworms. Carbonize it at 500℃ for 2 hours to obtain carbonized silkworm excrement. When used for processing, the cost is ≤0.1 yuan / kg of mulberry leaves. Weak alkalinity regulator: food-grade baking soda (sodium bicarbonate), to adjust the pH of the system to 7.5-8.0. When used for treatment, the cost is ≤0.1 yuan / kg of mulberry leaves.

[0023] Silkworm varieties: Suxiu × Chunfeng, which are conventional varieties. Each experimental treatment was fed one sheet (28,000 silkworms). Mulberry leaf variety: Yu 711.

[0024] Harvesting mulberry leaves: Harvest fresh mulberry leaves from the mulberry orchard after spraying with chlorantraniliprole (200 g / L suspension, diluted 1500 times) or bromocyanamide (10% bromocyanamide suspension, diluted 2500 times) or clean water for 20 days, and put them into 200L open plastic buckets, 50 kg per bucket.

[0025] Example 1 1. Add 1.5 liters of water to 1 kg of mulberry leaves. Pour the water into a 200L open plastic container, then add baking soda to dissolve until the pH is 7.6-7.7. Soak for 5 minutes. 2. Add 15g of carbonized silkworm excrement and 40mL of compound microbial agent to the above system, and stir until uniformly suspended; 3. Turn on the pulse magnetic field, turn on the power supply (12V), set the pulse frequency to 5Hz, and process for 20min; 4. After turning off the magnetic field, place the barrel in a normal temperature environment for 7 hours without stirring; 5. Then filter the mulberry leaves with a rope net, and the carbonized silkworm manure and the microbial agent are filtered (the residue after filtration can be used as organic fertilizer for field application, realizing resource recycling); 6. Rinse the mulberry leaves with clean water once (about 1 liter of water for 1 kilogram of mulberry leaves, with very little amount), and then dry naturally to remove the water content before feeding the silkworms.

[0026] Comparative Example 1 Referring to Example 1, a single bacterium is used as a comparison, i.e., using Rhodococcus or Klebsiella oxytoca liquid instead of Rhodococcus and Klebsiella oxytoca complex bacterial liquid, with the same amount of bacteria, and the rest is the same; the degradation of mulberry leaves, chlorantraniliprole and bromocyclenamide residues are 0.0012 mg / kg and 0.0014 mg / kg (Rhodococcus), respectively; chlorantraniliprole and bromocyclenamide residues are 0.0014 mg / kg and 0.0013 mg / kg (Klebsiella oxytoca), respectively.

[0027] Comparative Example 2 Referring to Example 1, omit the carbonized silkworm manure, and the rest is the same; the degradation of mulberry leaves, chlorantraniliprole and bromocyclenamide residues are 0.001 mg / kg and 0.0012 mg / kg, respectively.

[0028] Comparative Example 3 Referring to Example 1, omit the pulse magnetic field, and the rest is the same; the degradation of mulberry leaves, chlorantraniliprole and bromocyclenamide residues are 0.0018 mg / kg and 0.0016 mg / kg, respectively.

[0029] Comparative Example 4 The commonly used enzyme preparation (amidase + esterase / protease complex enzyme) in existing production was degraded by microorganisms according to the instructions, and the degradation time was 48h. The chlorantraniliprole and bromocyclenamide residues were 0.005 mg / kg and 0.004 mg / kg, respectively.

[0030] Example 2 Key Verification Index Residual amount: using high performance liquid chromatography (HPLC) detection, the residual amount of chlorantraniliprole and cyantraniliprole in mulberry leaves treated by example one was 0.0008 mg / kg and 0.0009 mg / kg respectively, both ≤0.001 mg / kg (far lower than the limit of 0.05 mg / kg specified in GB 2763-2021 for vegetable residues, and significantly lower than the 0.001 mg / kg limit for silkworm poisoning); before degradation, the residual amount of chlorantraniliprole and cyantraniliprole was 0.08 mg / kg and 0.07 mg / kg respectively.

[0031] Mulberry quality: after degradation, the crude protein content of mulberry leaves (21.3%±0.5%) and the chlorophyll content (1.8 mg / g±0.1 mg / g) had no significant difference from uncontaminated mulberry leaves (sprayed with water), and the feeding rate of silkworms reached 98%.

[0032] Environmental safety: the degradation products are carbon dioxide, water and small molecule amines, without secondary pollution; the residual amount of the bacterial agent is ≤5×10² CFU / g, which has no toxicity to silkworms.

[0033] Example three According to the conventional method, five-year-old silkworms were continuously fed with different treated mulberry silkworms to the upper cocoon, the number of poisoned heads was counted, the poisoning rate was calculated, and the amount of cocoon production (kg) was counted, as follows:

[0034] Summary, application advantages and cost analysis.

[0035]

Claims

1. A method for degrading benzamide insecticides on mulberry leaves, comprising the following steps: adding carbonized silkworm excrement and compound bacteria to weakly alkaline water containing mulberry leaves, then applying a pulsed magnetic field for 15-30 minutes; then turning off the pulsed magnetic field and letting it stand for 6-8 hours to complete the degradation of benzamide insecticides on mulberry leaves.

2. The method for degrading benzamide insecticides on mulberry leaves according to claim 1, characterized in that, The silkworm excrement is carbonized in an anaerobic environment to obtain carbonized silkworm excrement.

3. The method for degrading benzamide insecticides on mulberry leaves according to claim 1, characterized in that, The complex bacteria include Rhodococcus and Klebsiella acidogenic bacteria.

4. The method for degrading benzamide insecticides on mulberry leaves according to claim 1, characterized in that, The pH of weakly alkaline water is 7.5-8.

0.

5. The method for degrading benzamide insecticides on mulberry leaves according to claim 1, characterized in that, The voltage of the pulsed magnetic field is 12V, and the pulse frequency is 5Hz.

6. The application of the method for degrading benzamide insecticides on mulberry leaves according to claim 1 in the degradation of benzamide insecticides on mulberry leaves.

7. The benzamide insecticide prepared by the method for degrading benzamide insecticides on mulberry leaves according to claim 1 is used to degrade mulberry leaves.

8. The mulberry leaves degraded by the benzamide insecticide according to claim 7, characterized in that, Formamide insecticides include broflanilide and chlorantraniliprole.

9. A method for feeding silkworms, comprising the following steps: adding carbonized silkworm excrement and compound bacteria to weakly alkaline water containing mulberry leaves, then applying a pulsed magnetic field for 15-30 minutes; then turning off the pulsed magnetic field, letting it stand for 6-8 hours, then filtering, and then washing the mulberry leaves to obtain mulberry leaves with degraded benzamide insecticides; and then feeding silkworms with the mulberry leaves with degraded benzamide insecticides.

10. The application of the benzamide insecticide of claim 7 in the degradation of mulberry leaves in silkworm farming.

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