Quick-acting theasaponin composite plant nematode control agent as well as preparation method and application thereof

Abstract

The invention provides a quick-acting theasaponin composite plant nematode control agent, a preparation method and application, and the quick-acting theasaponin composite plant nematode control agent is prepared from the following raw materials in parts by weight: 10 parts of theasaponin, 1-2 parts of modified theasaponin, 0.5-1 part of isoprophos and 0.01-0.03 part of a cosolvent, the modified theasaponin is prepared by a method comprising the following steps: 1) carrying out esterification reaction on alcohol and an arteannuic acid derivative under the catalytic action of a catalyst to obtain an arteannuic acid ester derivative; and 2) carrying out transesterification on the arteannuic acid ester derivative and theasaponin under the catalytic action of a catalyst to obtain the modified theasaponin. The prevention and treatment agent is prepared by modifying theasaponin by using an arteannuic acid ester derivative with a terpenoid structure, the modified theasaponin has a good binding capacity with a plant nematode cell membrane, can enhance the permeability of the cell membrane and destroy the structure and function of the cell membrane, and can enable nematodes to die quickly in a short time by cooperating with a nerve toxic agent drug iprophos.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological control, and particularly relates to a quick-acting tea saponin composite plant nematode control agent, a preparation method and an application thereof. Background Art

[0002] Nematodes, also known as worms, belong to the phylum Nematoda of lower invertebrates. They are widely distributed in nature and have a wide variety of species. They exist in fresh water, sea water, deserts and various soils, and there are also many groups parasitic on animals, such as common roundworms and hookworms, which pose a threat to the health of humans and livestock; there are also some groups parasitic on plants, causing diseases to occur. These nematodes parasitic on plants are called plant parasitic nematodes. Plant parasitic nematodes are one of the plant infective pathogens. They are widely parasitic on the roots, stems, leaves, flowers, buds and seeds of various plants, causing various nematode diseases in plants, which has brought serious harm to the development of agriculture and forestry.

[0003] Tea saponin, also known as tea saponin, is a class of oleanane-type pentacyclic triterpenoid saponin compounds, which are composed of structural sugar, structural acid and triterpenoid saponin, and are widely present in the roots, stems, leaves, flowers and fruits of plants in the Theaceae family. As a plant-derived compound, tea saponin itself has various biological activities such as hemolytic effect, fish toxicity effect, oncomelania killing effect, insect resistance and bactericidal effect. Using it as an ingredient for controlling plant nematodes has attracted extensive attention from researchers. For example, a pesticide for controlling plant nematodes disclosed in Patent CN105145633B has an active ingredient including natural saponin, and the natural saponin is one or more of sapindus saponin, gleditsia saponin, tea saponin, bupleurum saponin, phytolacca saponin, ursolic acid, prunella saponin and begonia saponin. A nematocide composition containing dicyanothio methane disclosed in Patent CN106359379B has an active ingredient of the pesticide composition including dicyanothio methane and tea saponin, wherein the weight ratio of dicyanothio methane to tea saponin is 1:40 - 40:1, preferably 1:10 - 20:1. The application of tea saponin in controlling soybean cyst nematode diseases disclosed in Patent CN104068020B uses tea saponin as the main active ingredient, which has strong toxicicidal activity against Heterodera glycines and can be effectively used for controlling soybean cyst nematode diseases.

[0004] The above are the applications of tea saponin as an ingredient for controlling plant nematodes, which show relatively high toxicicidal activity against plant nematodes and can inhibit the growth and reproduction of nematodes and reduce their harm to plants to a certain extent. However, the effect takes effect slowly, especially the insecticidal mortality rate within 24 hours is low, and the control effect has a lag, which is not conducive to the rapid control of nematode outbreaks.

[0005] China ranks first in the world in terms of the output of camellia seeds. In the by-product camellia seed cake and meal after extracting camellia oil, the content of tea saponin can reach about 10%. If the nematicidal effect of the plant nematode control agent with tea saponin as the main component is improved, especially the ability to quickly kill nematodes, it is not only beneficial to the rapid control of nematode outbreaks, but also conducive to improving the economic value of camellia seed cake and meal. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a quick-acting tea saponin composite plant nematode control agent, a preparation method and an application. The control agent includes a modified tea saponin, which is prepared by modifying tea saponin with an artemisic acid ester derivative having a terpene structure. The modified tea saponin has good binding ability with the cell membrane of plant nematodes, can enhance the cell membrane permeability, destroy the structure and function of the cell membrane, and cooperate with the neurotoxic drug ethoprophos to cause nematodes to die within a short time.

[0007] To achieve the above object, the following technical solutions are adopted:

[0008] A quick-acting tea saponin composite plant nematode control agent, comprising the following raw materials in parts by weight: 10 parts of tea saponin, 1-2 parts of modified tea saponin, 0.5-1 part of ethoprophos, 0.01-0.03 part of cosolvent, and the modified tea saponin is prepared by a method comprising the following steps:

[0009] 1) Esterification reaction is carried out between an alcohol and an artemisic acid derivative under the catalysis of a catalyst to obtain an artemisic acid ester derivative;

[0010] 2) Transesterification reaction is carried out between the artemisic acid ester derivative and tea saponin under the catalysis of a catalyst to obtain a modified tea saponin.

[0011] In step 1), the alcohol is selected from one or a combination of two of methanol and ethanol. The artemisic acid derivative is selected from one or a combination of two of artemisic acid and dihydroartemisic acid. The catalyst is selected from one or a combination of two of p-toluenesulfonic acid and concentrated hydrochloric acid, preferably concentrated hydrochloric acid. The concentration of the concentrated hydrochloric acid is 36-38 wt%. The mass ratio of the artemisic acid derivative, alcohol, and catalyst is 1:600-800:5-8. Specifically, the preparation step of the artemisic acid ester derivative is: in an inert atmosphere, the artemisic acid derivative is dissolved in the alcohol, the catalyst is added, and the temperature is raised to the reflux state for reaction. After the reaction is completed, impurities are removed by distillation to obtain the artemisic acid ester derivative. The reaction time is 6-12 h.

[0012] In step 2), the mass ratio of the artemisic acid ester derivative, tea saponin, and catalyst is 0.25 - 0.45:1:0.01 - 0.03. Specifically, the preparation steps of the modified tea saponin are as follows: under an inert atmosphere, the artemisic acid ester derivative, tea saponin, and catalyst are added to an organic solvent and stirred until completely dissolved, then heated to the reflux state for reaction. After the reaction is completed, hexane is added until no precipitate is produced, and then it is filtered, washed, and dried to obtain the modified tea saponin. The organic solvent is selected from one or a combination of two or more of DMF and DMSO. The reaction time is 3 - 6 h, the washing is carried out 1 - 3 times with ethanol, and the drying is carried out under a vacuum of 60 - 100 °C and 0.01 - 0.1 MPa for 12 h. The catalyst is selected from one or a combination of two of p-toluenesulfonic acid, sodium methoxide, sodium hydroxide, and potassium hydroxide, and preferably p-toluenesulfonic acid.

[0013] The co-solvent is selected from one or a combination of two or more of Tween 80, Tween 60, and Tween 40.

[0014] The present invention provides a preparation method of the above-mentioned fast-acting tea saponin composite plant nematode control agent, which includes the following steps:

[0015] Mix tea saponin, modified tea saponin, ethoprophos, and co-solvent evenly to obtain the tea saponin composite plant nematode control agent.

[0016] The present invention also provides an application of the fast-acting tea saponin composite plant nematode control agent in controlling plant nematodes. The above-mentioned tea saponin composite plant nematode control agent is dissolved and diluted with water into an aqueous solution, and is applied to plants by spraying, seed dressing, flushing, or injection.

[0017] The content of the tea saponin composite plant nematode control agent in the aqueous solution is 3 - 5 g / L.

[0018] The plants are selected from one or a combination of two of crops and forest trees.

[0019] The dosage of spraying is 150 - 250 ml / mu. The dosage of injection is 3.5 - 4.5 ml / cm of breast diameter. The dosage of seed dressing is that the mass ratio of the aqueous solution to wheat seeds is 1:5 - 8. The dosage of flushing is 3 - 5 L / mu.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] The control agent of the present invention includes a modified tea saponin, which is prepared by modifying tea saponin with an artemisic acid ester derivative having a terpene structure. The modified tea saponin has a good binding ability with the cell membrane of plant nematodes, can enhance the cell membrane permeability, destroy the structure and function of the cell membrane, and cooperate with the nerve poison ethoprophos, so that nematodes can die quickly in a short time. Specific embodiments

[0022] The present invention will be further described below in conjunction with specific embodiments, but it is not limited to the content in the specification. Unless otherwise specified, "parts" in the embodiments of the present invention are all parts by weight. The reagents used are all commercially available reagents in the art.

[0023] Example 1

[0024] 1) Under a nitrogen atmosphere, 100 g of artemisinic acid was dissolved in 60 kg of methanol, 500 g of concentrated hydrochloric acid with a concentration of 37 wt% was added, and the temperature was raised to the reflux state for reaction for 12 h. After the reaction, impurities were removed by distillation to obtain an artemisinic acid ester derivative.

[0025]

[0026] 2) 45 g of the artemisinic acid ester derivative prepared in step 1), 100 g of tea saponin, and 1 g of p-toluenesulfonic acid were added to 300 g of DMSO and stirred until completely dissolved. The temperature was raised to the reflux state for reaction for 6 h. After the reaction, hexane was added until no precipitation occurred, and then it was filtered, washed with ethanol 3 times, and dried at 60 °C under a vacuum of 0.08 MPa to obtain modified tea saponin.

[0027] 3) 100 g of tea saponin, 20 g of modified tea saponin, 10 g of ethoprophos, and 0.3 g of Tween 80 were mixed evenly to obtain a tea saponin composite plant nematode control agent.

[0028] 4) The tea saponin composite plant nematode control agent was added to sterilized water to dissolve and dilute to prepare an aqueous solution with a tea saponin composite plant nematode control agent content of 5 g / L.

[0029] Example 2

[0030] The rest is the same as in Example 1, except that in step 1), dihydroartemisinic acid with the same mass was used to replace artemisinic acid.

[0031] Example 3

[0032] The rest is the same as in Example 1, except that in step 2), the amount of the artemisinic acid ester derivative prepared in step 1) was 25 g.

[0033] Example 4

[0034] The rest is the same as in Example 1, except that in step 3), the amount of modified tea saponin was 10 g.

[0035] Example 5

[0036] The rest is the same as in Example 1, except that in step 3), the amount of ethoprophos was 5 g.

[0037] Example 6

[0038] 1) Under a nitrogen atmosphere, dissolve 100 g of artemisic acid in 80 kg of methanol, add 800 g of concentrated hydrochloric acid with a concentration of 37 wt%, heat up to the reflux state and react for 12 h. After the reaction is completed, distill to remove impurities to obtain an artemisic acid ester derivative;

[0039] 2) Under a nitrogen atmosphere, take 25 g of the artemisic acid ester derivative prepared by the method in step 1), 100 g of tea saponin, and 3 g of p-toluenesulfonic acid, add them to 300 g of DMSO and stir until completely dissolved. Heat up to the reflux state and react for 6 h. After the reaction is completed, add hexane until no precipitation occurs, filter, wash with ethanol 3 times, and dry at 60 °C under a vacuum of 0.08 MPa to obtain modified tea saponin;

[0040] 3) Mix 100 g of tea saponin, 20 g of modified tea saponin, 5 g of ethoprophos, and 0.3 g of Tween 80 evenly to obtain a tea saponin composite plant nematode control agent.

[0041] 4) Add the tea saponin composite plant nematode control agent to sterilized water to dissolve and dilute it to prepare an aqueous solution with a tea saponin composite plant nematode control agent content of 5 g / L.

[0042] Comparative Example 1

[0043] 1) Mix 120 g of tea saponin, 10 g of ethoprophos, and 0.3 g of Tween 80 evenly to obtain a tea saponin composite plant nematode control agent.

[0044] 2) Add the tea saponin composite plant nematode control agent to sterilized water to dissolve and dilute it to prepare an aqueous solution with a tea saponin composite plant nematode control agent content of 5 g / L.

[0045] Comparative Example 2

[0046] The rest is the same as in Example 1, except that in step 3), emamectin benzoate of equal mass is used to replace ethoprophos.

[0047] Application Example

[0048] Indoor in vitro determination of the activity against Bursaphelenchus xylophilus: Bursaphelenchus xylophilus was collected from Jiuchi Street, Wanzhou District, Chongqing City, cultured using Botrytis cinerea as a nutrient source, after single-female purification culture, propagated with corn kernel medium, collected second-stage larvae, and added sterile water to prepare a suspension of 500 individuals / mL for standby. Using the impregnation method, add 1 mL of the suspension to a transparent culture dish, add 2 mL of the aqueous solution prepared in the above-mentioned example or comparative example, use sterile water as a control, place it in a constant temperature incubator at 26 °C for culture, take 100 μL of the solution on a watch glass at 24 h, 48 h, and 72 h respectively, and detect the number of dead nematodes under a binocular dissecting microscope. Nematodes that are rigid and motionless are judged as dead. When the mortality rate is lower than 5%, no correction calculation is made. Calculate the corrected mortality rate according to the following formula:

[0049] Treatment mortality rate = (Number of dead nematodes / Number of test nematodes) × 100%

[0050] Corrected mortality rate = (Treatment mortality rate - Control mortality rate) / (1 - Control mortality rate) × 100%

[0051] Table 1 Performance test results

[0052]

[0053] It can be seen from the test results in Table 1 that the tea saponin composite plant nematode control agent prepared by the present invention can quickly kill nematodes. The corrected mortality rate can reach up to 92.5% at 24 h, and is even higher at 72 h, showing obvious effects of increasing production and ensuring harvest.

[0054] The above detailed description is a specific description of one feasible embodiment of the present invention. This embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or change without departing from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A fast-acting tea saponin composite plant nematode control agent, characterized in that: The invention comprises the following raw materials in parts by weight: 10 parts of tea saponin, 1-2 parts of modified tea saponin, 0.5-1 parts of ethoprophos, and 0.01-0.03 parts of a solvent. The modified tea saponin is prepared by a method comprising the following steps: 1) using alcohol and artemisinic acid derivative to carry out esterification reaction under the catalysis of a catalyst to obtain artemisinic acid ester derivative; 2) Artemisinic acid ester derivatives and tea saponin undergo ester exchange reaction under the catalysis of a catalyst to obtain modified tea saponin.

2. The fast-acting tea saponin composite plant nematode control agent according to claim 1, characterized in that: In step 1), the artemisinic acid derivative is selected from artemisinic acid, dihydroartemisinic acid or a combination of both; the alcohol is selected from methanol and ethanol or a combination of both; the catalyst is selected from p-toluenesulfonic acid and concentrated hydrochloric acid or a combination of both, preferably concentrated hydrochloric acid; the concentration of the concentrated hydrochloric acid is 36-38wt%.

3. The fast-acting tea saponin composite plant nematode control agent according to claim 1, characterized in that: In step 1), the mass ratio of the artemisinic acid derivative, alcohol and catalyst is 1:600-800:5-8.

4. The fast-acting tea saponin composite plant nematode control agent according to claim 1, characterized in that: In step 1), the preparation steps of the artemisinic acid ester derivative are as follows: in an inert atmosphere, the artemisinic acid derivative is dissolved in alcohol, a catalyst is added, the temperature is raised to reflux state for reaction, and after the reaction is completed, impurities are removed by distillation to obtain the artemisinic acid ester derivative.

5. The fast-acting tea saponin composite plant nematode control agent according to claim 1, characterized in that: In step 2), the mass ratio of the artemisinic acid ester derivative, tea saponin and catalyst is 0.25-0.45:1:0.01-0.

03.

6. The fast-acting tea saponin composite plant nematode control agent according to claim 1, characterized in that: In step 2), the preparation steps of the modified tea saponin are as follows: in an inert atmosphere, artemisinic acid ester derivative, tea saponin, and catalyst are added to an organic solvent and stirred until completely dissolved, the temperature is raised to reflux state for reaction, and after the reaction is completed, hexane is added until no precipitation is produced, and the modified tea saponin is obtained by filtering, washing, and drying.

7. The fast-acting tea saponin composite plant nematode control agent according to claim 1, characterized in that: In step 2), the catalyst is selected from p-toluenesulfonic acid, sodium methoxide, sodium hydroxide, potassium hydroxide, or a combination of two thereof, preferably p-toluenesulfonic acid.

8. The method for preparing the fast-acting tea saponin composite plant nematode control agent according to any one of claims 1 to 7, characterized in that: The steps include: The tea saponin, modified tea saponin, ethoxyprolin and a solvent are uniformly mixed to obtain a tea saponin composite plant nematode control agent.

9. Use of a fast-acting tea saponin compound plant nematode control agent in controlling plant nematodes, comprising dissolving the tea saponin compound plant nematode control agent according to any one of claims 1 to 7 in water, diluting it into an aqueous solution, and applying it to plants by spraying, seed mixing, flushing or injection.

10. The use of the fast-acting tea saponin composite plant nematode control agent according to claim 9 in controlling plant nematodes, characterized in that: The content of the tea saponin composite plant nematode control agent in the aqueous solution is 3-5 g / L.

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