Pesticide composition containing paecilomyces lilacinus and application of pesticide composition in killing root-knot nematode

Abstract

The invention relates to the technical field of pesticides, and provides a pesticide composition containing paecilomyces lilacinus and application of the pesticide composition in killing root-knot nematodes. The pesticide composition containing paecilomyces lilacinus comprises bacterial powder and modified chitosan in a mass ratio of (5: 3)-(9: 1), the modified chitosan is obtained by modifying chitosan with a phosphate compound, and the bacterial powder comprises paecilomyces lilacinus, trichoderma harzianum, bacillus cereus and paenibacillus polymyxa. According to the technical scheme, the problem of poor nematode control effect of a paecilomyces lilacinus preparation in the prior art is solved.

Description

Technical Field

[0001] The invention relates to the technical field of pesticides, and in particular to a pesticide composition containing Paecilomyces lilacinus and an application thereof in killing root-knot nematodes. Background Art

[0002] Nematodes are a type of lower animals with many species and wide distribution. They can parasitize on plants and cause plant nematode diseases. Currently, the biological pesticides with good effects in preventing and controlling nematodes are mainly: avermectin, Paecilomyces lilacinus, matrine, actinomycetes, etc. Paecilomyces lilacinus is the most widely used because of its fast reproduction speed, strong vitality, safety and low toxicity. It can not only reduce the damage of root-knot nematode diseases of various crops, but also reduce the damage of plant nematode diseases such as cyst nematodes and stem nematodes.

[0003] At present, the commonly used dosage form of Paecilomyces lilacinus is granules, and the working principle is that the hyphae of Paecilomyces lilacinus invade the body and eggs of nematodes to reproduce, destroying the physiological activities of nematodes and causing death. However, the existing Paecilomyces lilacinus preparations on the market are not ideal for the prevention and control of nematodes. Summary of the invention

[0004] The invention provides a pesticide composition containing Paecilomyces lilacinus and application thereof in killing root-knot nematodes, thereby solving the problem that the Paecilomyces lilacinus preparation in the related art has a poor control effect on nematodes.

[0005] The technical solution of the present invention is as follows: The pesticide composition containing Paecilomyces lilacinus comprises bacterial powder and modified chitosan in a mass ratio of 5:3 to 9:1, wherein the modified chitosan is obtained by modifying chitosan with a phosphate compound, and the bacterial powder comprises Paecilomyces lilacinus, Trichoderma harzianum, Bacillus cereus and Paenibacillus polymyxa.

[0006] As a further technical solution, the mass ratio of the Paecilomyces lilacinus, Trichoderma harzianum, Bacillus cereus and Paenibacillus polymyxa is 15-20:5-10:2:8.

[0007] During the research process, the inventors conducted a systematic study on the mass ratio of the four fungal powders and found that when the mass ratio of Paecilomyces lilacinus, Trichoderma harzianum, Bacillus cereus and Bacillus polymyxa was 15~20:5~10:2:8, the pesticide composition containing Paecilomyces lilacinus had a better control effect on nematodes. When the mass ratio exceeded this range, the control effect on nematodes decreased. Therefore, the mass ratio of the four was optimized to 15~20:5~10:2:8.

[0008] As a further technical solution, the raw materials of the modified chitosan include a phosphate compound and chitosan in a mass ratio of 0.5 to 3:10, preferably a phosphate compound and chitosan in a mass ratio of 1.5:10.

[0009] In the present invention, the phosphate compound can be any one or more compounds containing a phosphate group in the art, for example, acetyl phosphate, glycerophosphate, methylene diphosphate, 1,6-diphosphate fructose, 5-pyridoxal phosphate, etc. The inventors found in the modification process that the phosphate compound and chitosan in a mass ratio of 0.5 to 3:10 are used as raw materials, and the modification effect on chitosan is better, and the modification effect is best when the mass ratio is 1.5:10, and the prepared pesticide composition containing Paecilomyces lilacinus has a good control effect on nematodes.

[0010] As a further technical solution, the phosphate compound includes methylene diphosphoric acid or fructose 1,6-diphosphate.

[0011] As a further technical solution, the phosphate compound is fructose 1,6-diphosphate.

[0012] The inventors have found through research that when chitosan is modified with 1,6-diphosphate fructose, the adsorption sites on the surface of the modified chitosan are increased due to the hydroxyl group contained in 1,6-diphosphate fructose, which further improves the control effect of the pesticide composition containing Paecilomyces lilacinus on nematodes.

[0013] As a further technical solution, the preparation method of the modified chitosan comprises the following steps: dissolving a phosphate compound in a solvent, adding chitosan for modification, and drying to obtain the modified chitosan.

[0014] As a further technical solution, the modification temperature is 30-40° C., and the modification time is 5-10 hours.

[0015] As a further technical solution, the solvent is water.

[0016] The solvent in the present invention may be any one or more solvents that can dissolve the phosphate-based compound, preferably water.

[0017] The invention also provides a method for preparing the pesticide composition containing Paecilomyces lilacinus, which comprises the following steps: mixing bacterial powder and modified chitosan to obtain the pesticide composition containing Paecilomyces lilacinus.

[0018] The present invention also proposes the use of the pesticide composition containing Paecilomyces lilacinus or the pesticide composition prepared by the preparation method in killing root-knot nematodes.

[0019] The working principle and beneficial effects of the present invention are: 1. In the present invention, the pesticide composition containing Paecilomyces lilacinus includes bacterial powder and modified chitosan. The modified chitosan is used as a carrier, and Paecilomyces lilacinus, Trichoderma harzianum, Bacillus cereus and Paenibacillus polymyxa are used as bacterial powder. It can not only prevent and control root-knot nematodes of various crops, but also has the characteristics of safety to humans, animals and the environment, high efficiency, long lasting effect, etc.

[0020] 2. In the present invention, modified chitosan is used as a carrier. After chitosan is modified by a phosphate compound, since the phosphate group in the phosphate compound carries a negative charge, it can combine with the amino positive charge of chitosan, thereby reducing the antibacterial effect of chitosan and improving the activity of the bacterial powder when chitosan is used in combination with bacterial powder, thereby improving the control effect of the pesticide composition containing Paecilomyces lilacinus on nematodes. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The parameters of the raw materials in the following examples and comparative examples are as follows: The content of effective substances in the powder of Paecilomyces lilacinus is 5 billion cfu / g; The effective substance content in Trichoderma harzianum powder is 2 billion cfu / g; The effective substance content of Bacillus cereus is 5 billion cfu / g; The effective substance content of Paenibacillus polymyxa is 2 billion cfu / g; Chitosan: Deacetylation degree 90%, weight average molecular weight 200,000.

[0023] Example 1 S1, dissolving 2.5 g of methylene diphosphoric acid in 80 mL of water, adding 50 g of chitosan, modifying at 30°C and 400 rpm for 10 h, and drying to obtain modified chitosan; S2, mixing the powder of Paecilomyces lilacinus, the powder of Trichoderma harzianum, the powder of Bacillus cereus and the powder of Paenibacillus polymyxa in a mass ratio of 15:5:2:8 to obtain a fungus powder; S3. Evenly mix the bacterial powder and modified chitosan in a mass ratio of 9:1 to obtain a pesticide composition containing Paecilomyces lilacinus.

[0024] Example 2 S1, dissolving 2.5 g of methylene diphosphoric acid in 80 mL of water, adding 50 g of chitosan, modifying at 40°C and 300 rpm for 5 h, and drying to obtain modified chitosan; S2, mixing the powder of Paecilomyces lilacinus, the powder of Trichoderma harzianum, the powder of Bacillus cereus and the powder of Paenibacillus polymyxa in a mass ratio of 20:10:2:8 to obtain a fungus powder; S3. Evenly mix the bacterial powder and the modified chitosan in a mass ratio of 5:3 to obtain a pesticide composition containing Paecilomyces lilacinus.

[0025] Example 3 The difference from Example 1 is only that: 7.5 g of methylene diphosphoric acid.

[0026] Example 4 The difference from Example 1 is only that: 15 g of methylene diphosphoric acid.

[0027] Example 5 The only difference from Example 3 is that methylene diphosphoric acid is replaced by an equal amount of fructose 1,6-diphosphate.

[0028] Comparative Example 1 S1. Mixing the powder of Paecilomyces lilacinus, the powder of Trichoderma harzianum, the powder of Bacillus cereus and the powder of Paenibacillus polymyxa in a mass ratio of 15:5:2:8 to obtain a fungus powder; S2. Evenly mix the bacterial powder and chitosan in a mass ratio of 1:3 to obtain a pesticide composition containing Paecilomyces lilacinus.

[0029] Experimental Example 1 The mortality rates of the pesticide compositions obtained in Examples 1 to 5 and Comparative Example 1 against root-knot nematodes were measured respectively: (1) After disinfecting and rinsing the root-knot nematode oocysts of the same size, they were cultured in a culture dish at 26°C in the dark for 7 days to obtain the second-instar larvae of the root-knot nematode; (2) mixing the pesticide composition and sterile water at a ratio of 1 g:10 mL, and shaking to prepare a suspension; (3) Dilute the second-instar larvae of root-knot nematodes with sterile water to 100 larvae / mL to obtain an insect suspension; (4) Use a 12-well plate and add 1 mL of the suspension and 1 mL of the worm suspension to each well. At the same time, add 1 mL of sterile water to 1 mL of the worm suspension as a control group. Place the plates in a 28°C incubator in the dark for 72 h. Observe the number of dead root-knot nematodes and the total number of root-knot nematodes under a dissecting microscope at room temperature (the nematodes are stiff and inactive when touched by a dissecting needle). Calculate the mortality rate according to the following formula: Mortality rate = (number of root-knot nematodes killed ÷ total number of root-knot nematodes) × 100%; Each treatment was repeated 5 times, and the average value was recorded as the final result, as shown in Table 1.

[0030] Table 1 Mortality of root-knot nematodes

[0031] It can be seen from Table 1 that, compared with Comparative Example 1, the mortality rate of the pesticide composition containing Paecilomyces lilacinus obtained in Examples 1 to 5 against root-knot nematodes is above 91.4%, indicating that after chitosan is modified with a phosphate compound, the control effect of the pesticide composition containing Paecilomyces lilacinus on nematodes is improved.

[0032] Experimental Example 2 Pot experiment: (1) Mix the pesticide composition and sterile water in a ratio of 0.1 g:10 mL, and shake to prepare a suspension; (2) In the Wanggezhuang experimental field in Laoshan District, Qingdao, a tomato greenhouse with serious root-knot nematode damage was selected to collect root-knot nematodes and soil. The diseased roots were chopped up and mixed with soil and then placed in flower pots. Four-leaf-old tomato seedlings were transplanted, with three seedlings per pot, and cultivated in a triangular distribution pattern. On the third day after transplanting, the surrounding area of ​​the plants was treated with 0.5 g of the pesticide composition per plant. The control group was treated with 50 mL of sterile water. The subsequent water and fertilizer management methods were uniformly followed. (3) The root-knot nematode situation in the soil was investigated before and 60 days after treatment. The investigation method was as follows: 100g of soil from the rhizosphere was taken and the nematodes were separated using the modified Baermann funnel method. After the nematode liquid was collected and allowed to stand for 2 hours, 2 / 3 of the supernatant was aspirated and 100℃ boiling water was added to kill the nematodes. The nematodes were observed and counted under a microscope. The population reduction rate and control effect were calculated according to the following formula: Insect population reduction rate = (insect population before treatment - insect population after treatment) ÷ insect population before treatment × 100%; Pest control effect = (pest reduction rate of treatment - pest reduction rate of control group) ÷ (1 - pest reduction rate of control group) × 100%; Each treatment was repeated 5 times, and the average value was recorded as the final result, as shown in Table 2.

[0033] Table 2 Insect population reduction rate and insect population control effect

[0034] It can be seen from Table 2 that, compared with Comparative Example 1, the insect population reduction rate and insect population control effect of the pesticide composition containing Paecilomyces lilacinus obtained in Examples 1 to 5 are higher, indicating that after chitosan is modified with a phosphate compound, the control effect of the pesticide composition containing Paecilomyces lilacinus on nematodes is improved.

[0035] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A pesticide composition containing Paecilomyces lilacinus, characterized in that: The invention comprises bacterial powder and modified chitosan in a mass ratio of 5:3 to 9:1, wherein the modified chitosan is obtained by modifying chitosan with a phosphate compound, and the bacterial powder comprises Paecilomyces lilacinus, Trichoderma harzianum, Bacillus cereus and Paenibacillus polymyxa.

2. The pesticide composition containing Paecilomyces lilacinus according to claim 1, characterized in that: The mass ratio of the Paecilomyces lilacinus, Trichoderma harzianum, Bacillus cereus and Paenibacillus polymyxa is 15-20:5-10:2:

8.

3. The pesticide composition containing Paecilomyces lilacinus according to claim 1, characterized in that: The raw materials of the modified chitosan include a phosphate compound and chitosan in a mass ratio of 0.5 to 3:

10.

4. The pesticide composition containing Paecilomyces lilacinus according to claim 3, characterized in that: The phosphate-based compound includes methylene diphosphoric acid or fructose 1,6-diphosphate.

5. The pesticide composition containing Paecilomyces lilacinus according to claim 4, characterized in that: The phosphate compound is fructose 1,6-diphosphate.

6. The pesticide composition containing Paecilomyces lilacinus according to claim 3, characterized in that: The preparation method of the modified chitosan comprises the following steps: dissolving a phosphate compound in a solvent, adding chitosan for modification, and drying to obtain the modified chitosan.

7. The pesticide composition containing Paecilomyces lilacinus according to claim 6, characterized in that: The modification temperature is 30-40° C., and the modification time is 5-10 hours.

8. The pesticide composition containing Paecilomyces lilacinus according to claim 6, characterized in that: The solvent is water.

9. The method for preparing a pesticide composition containing Paecilomyces lilacinus according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing bacterial powder and modified chitosan to obtain a pesticide composition containing Paecilomyces lilacinus.

10. Use of the pesticide composition containing Paecilomyces lilacinus according to any one of claims 1 to 8 or the pesticide composition prepared by the preparation method according to claim 9 in killing root-knot nematodes.

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