Application of gnetum macrophyllum extract in preparation of nematicide

Abstract

The invention discloses an application of a gnetum macrophyllum extract in preparation of a nematicide. The gnetum giganteum extract can be used for preventing and treating potato stem nematode Ditylenchus destructor on crops such as potatoes and sweet potatoes, not only has a good nematode killing effect, but also is safe to the environment, human, livestock, natural enemies of pests and other beneficial organisms. The nematicide is simple in preparation process, low in cost and suitable for popularization and application.

Description

Technical Field

[0001] The invention belongs to the field of plants and their applications, and particularly relates to a Gnetum macrophylla nematicide and a preparation method thereof. Background Art

[0002] Potato stem nematode Ditylenchus destructor Thorne, belonging to the order Pseudocerma, family Graminaceae, genus Ditylenchus, is an important parasitic nematode. Its host plants are potatoes and sweet potatoes, but in my country, the main damage is to sweet potatoes, and it occurs in both the northern and southern potato regions. Potato stem nematodes only harm the underground part of the host. The infected sweet potato tissue rots, dries, shrinks, the epidermis cracks, and the internal tissue gradually turns black. It is usually accompanied by secondary infection by fungi, bacteria, and mites. In recent years, the stem nematode disease has become more serious year by year, posing a serious threat to the production of sweet potatoes. It has become one of the three major diseases that restrict the production of sweet potatoes in my country. Generally, the yield of the diseased fields is reduced by 20% to 50%, and the seriously diseased fields are basically completely harvested. Summary of the invention

[0003] Based on the research findings of the inventors, the present invention provides the use of a Gnetum macrophylla extract for preparing a nematicide, wherein the Gnetum macrophylla extract is an organic solvent extract of Gnetum macrophylla, and the nematode is Ditylenchus potatoein.

[0004] An optional solution is that the Gnaphalium macrophyllum extract is a methanol extract of Gnaphalium macrophyllum.

[0005] An optional solution is that the preparation method of the Gnaphalium macrophylla extract comprises: A. Grind the large-leaved Gnaphalium wilfordii into pieces of 1-5 mm to obtain a coarsely ground product; B. The coarsely ground product obtained in step A is extracted with an organic solvent under ultrasonic conditions at 25-35° C. for 0.5-1 hour; the obtained extract is concentrated by vacuum concentration to obtain the Gnaphalium macrophylla extract.

[0006] The invention also provides a Gnetum macrophylla nematicide, wherein the nematode is Ditylenchus potatoein, and the active component of the nematicide is an organic solvent extract of Gnetum macrophylla; the preparation form of the nematicide is a soluble liquid.

[0007] An optional solution is that the nematicide contains 20% to 50% of the Gnetum chinense extract; the Gnetum chinense extract is an extract obtained by extracting 1 kg of dried Gnetum chinense with 5 to 10 kg of organic solvent and concentrating the extract to 1 kg.

[0008] An optional solution is that the raw materials for preparing the nematicide include the following components in percentage by mass: 20% to 50% of Gnaphalium macrophyllum extract, 5% to 40% of organic solvent, 5% to 40% of surfactant, and 5% to 10% of antifreeze agent, and the sum of the percentages by mass of the above components is 100%; The extract of Gnetum chinense is prepared by extracting 1 kg of dried Gnetum chinense with 5 to 10 kg of organic solvent, and concentrating the extract to 1 kg; The organic solvent is one or a mixture of two or more of ethyl acetate, cyclohexanone, methyl oleate, ethanol, methanol, acetone, dimethylformamide, ethylbenzene and xylene; The surfactant is one or a mixture of two or more of alkylbenzene sulfonates, alkylphenol polyoxyethylene ethers, phenethylphenol polyoxyethylene ethers, phenethylphenol polyoxyethylene ether polyoxypropylene ethers and similar substances, adducts of castor oil and ethylene oxide, and arylalkylphenol polyoxyethylene ether formaldehyde condensates; The antifreeze agent is ethylene glycol, polyethylene glycol, glycerol, propylene glycol or urea.

[0009] The organic solvent extract of Gnaphalium macrophyllum has significant nematicidal activity and can be used to kill potato stem nematodes on crops such as potatoes and sweet potatoes. Ditylenchus destructor and develop it into pesticides that are safe for humans, livestock, natural enemies of pests and other beneficial organisms, and have good environmental compatibility; and it is a bio-source pesticide with no residual toxicity after use. DETAILED DESCRIPTION

[0010] Unless otherwise specified, the scientific and technical terms used herein are understood according to the knowledge of ordinary technicians in the relevant fields.

[0011] Gnaphalium macrophylla Gnetummontanum ) is a large vine plant of the Gnetaceae family and the genus Gnetum. Large-leaf Gnetum grows in forests at an altitude of 1,600-2,000 meters and entwines on trees. When used as medicine, large-leaf Gnetum can dispel wind and dampness, promote blood circulation and disperse blood stasis. The stems and leaves can treat injuries from falls and rheumatism and bone pain.

[0012] The extract of Gnetum chinense of the present invention is a concentrate extracted from the crushed material of Gnetum chinense with an organic solvent, preferably methanol, i.e. the organic solvent extract of Gnetum chinense. The preferred extraction conditions are ultrasound and room temperature.

[0013] The botanical nematicide of the present invention uses the extract of Gnaphalium macrophyllum as the active substance, and adds a certain proportion of auxiliary agents for dosage form processing, so as to prepare an environmentally friendly preparation microemulsion and a soluble liquid. Personnel in the art can optimize the relevant components and their contents within the scope of the present invention to obtain a nematicide with an ideal control effect.

[0014] In order to better understand the essence of the invention, the following examples are used to describe the technical content of the invention in detail, but the invention is not limited to these examples. Among the components selected in the following examples, 20% of the microemulsion of Gnetum chinense and 20% of the soluble liquid of Gnetum chinense have good control effects on potato stem nematodes.

[0015] Embodiment 1: The extraction method of the methanol extract of Gnetum chinense of this embodiment comprises: A. Grind the large-leaved Gnaphalium wilfordii into coarse powder of 1 to 5 mm using a plant grinder; B. The coarsely ground material obtained in step A is extracted with methanol (the mass ratio of the coarsely ground material to methanol is 1 kg:9 kg), the extraction method is ultrasonic extraction, the extraction temperature is 30°C, the extraction time is 1 hour, the extract is filtered, and the extract is concentrated to 1 kg by vacuum.

[0016] Indoor bioassay results of methanol extract of Gnetum chinense against nematodes: The nematodes with healthy growth and uniform size were selected as the test nematodes to determine the toxicity of the drug solution of Gnaphalium macrophyllum. The test was carried out in a 24-well cell culture plate. The same volume (V1) of the nematode suspension was first injected into the sample well, and then the sterile water (V2) needed to be added according to the test concentration [calculated according to formula (3)] was added. Finally, the corresponding amount of drug mother solution (V3) was added, mixed evenly, and placed in a 25℃ incubator. Each treatment was repeated 3 times, with 80 nematodes in each repeat, and methanol treatment was used as the control; after 24h and 48h of treatment, the death and survival of nematodes in each treatment were checked respectively, and the nematode mortality rate and the nematode corrected mortality rate were calculated according to formula (1) and formula (2), respectively.

[0017] Method for judging whether nematodes are dead or alive: observe under a microscope. Those that are swimming and in an "S" shape are recorded as alive. For nematodes in a "straight line" or "half-moon" shape, touch the nematodes' bodies with eyelashes repeatedly. Those that change shape obviously after being touched are recorded as alive. Otherwise, they are recorded as dead.

[0018] …… ... … (2) …… ... In the formula, V = volume of nematode suspension V1 + supplemented sterile water volume V2 + drug stock solution volume V3; V = 400 μL; V1 = 100 μL; In the experiment, N is set in advance, and in this embodiment, N=200 mgDW / mL; to ensure the consistency of the number of treated nematodes, N0 is known, and in this embodiment, N0=400 mgDW / mL, then V is fixed, and V2 and V3 of different treatments can generally be obtained based on this.

[0019] The toxicity of Gnaphalium macrophyllum to nematodes was determined by the drug solution immersion method, and the toxicity curve was drawn. The results are shown in Tables 1 and 2.

[0020] Table 1 Gnaphalium macrophylla ( G.montanum ) Toxic effect of methanol extract on potato stem nematode (200mgDW / mL)

[0021] Table 2 Gnaphalium macrophyllum ( G.montanum Toxicity curve of methanol extract against Ditylenchus edulis

[0022] As shown in the table above, the methanol extract of Gnaphalium macrophyllum has toxic activity against Ditylenchus potatoein. When treated with 200 mg DW / mL of Ditylenchus potatoein, the corrected mortality rate at 48 h reached more than 80%. The LC values ​​of Ditylenchus potatoein at 24 h and 48 h were 50 They were 62.64 and 56.60 mgDW / mL respectively.

[0023] Embodiment 2: This example is the preparation of a 50% Gnetum macrophylla extract microemulsion.

[0024] Specifically, 50 kg of Gnaphalium macrophyllum concentrate was dissolved in 25 kg of methanol, and then 15 kg of calcium dodecylbenzene sulfonate, 5 kg of polyoxyethylene styrene acid ether, and 5 kg of ethylene glycol were added, mixed under high-speed stirring, and heated to about 40° C.; high-speed stirring was performed to mix well to obtain 100 kg of 20% Gnaphalium macrophyllum extract microemulsion of this embodiment. The stability and appearance of the preparation met the requirements of commercial preparations.

[0025] Embodiment 3: This example is the preparation of a 20% soluble liquid of the extract of Gnaphalium truncatum. Specifically, 20 kg of Gnaphalium truncatum concentrate was dissolved in 40 kg of methanol, 35 kg of sodium dodecylbenzene sulfonate and 5 kg of propylene glycol were added under stirring, and 100 kg of the soluble liquid of the extract of Gnaphalium truncatum in this example was obtained after uniform mixing. The stability and appearance of the preparation met the requirements of commercial preparations.

[0026] Embodiment 4: This example shows the field control effect of the extract preparation of Gnaphalium truncatum of Example 2-3 on Ditylenchus edulis.

[0027] 1. Test reagents: Example 2 and Example 3: Soluble liquid preparation of Gnetum chinense extract; 1.8% avermectin emulsifiable concentrate (Jiangsu Suling Pesticide Chemical Co., Ltd.).

[0028] 2. Test crops: Potatoes, variety "Purple Flower White".

[0029] 3. Targets of prevention and treatment: Potato stem nematode ( Ditylenchus destructor ) 4. Selection of test plots and test treatment: 4.1 Selection of experimental plots This experiment was conducted at the greenhouse vegetable base in Dazhai Village, Yangcun Township, Yangling District, Shaanxi Province. A representative potato plot with disease incidence was selected as the test site. The previous crop of potatoes was planted, and the potato stem nematode occurred evenly, single and serious, while other diseases and pests were mild. The soil was sandy loam, with a light texture, high nutrient content, and normal fertilizer and water management.

[0030] 4.2 Experimental treatment and plot design The test agents were 100-fold, 300-fold and 500-fold dilutions of the extract of Gnaphalium macrophylla; 500-fold dilution of 1.8% avermectin emulsifiable concentrate and a blank control (water). The experimental plots were arranged in random blocks, with an area of ​​25 m 2 , repeat 3 times.

[0031] 4.3 Application method Before treatment, each plot was irrigated to ensure that the soil moisture content reached 60% to 70% of the saturated water holding capacity. Before application, the soil was tilled to a depth of 20 to 30 cm. The agent was evenly sprayed on the soil surface at a spray rate of 50 L / mu and then tilled again to fully mix the agent with the soil before planting. 1.8% avermectin emulsifiable concentrate 500× and clean water were used as agent control and blank control, respectively, and normal water and fertilizer management was carried out. During the experiment, the temperature in the greenhouse was low, with the highest temperature at 30°C and the lowest temperature at 20°C. Sampling was conducted after 45 days.

[0032] 4.4 Survey Methods The "Z"-shaped sampling method was used for sampling, with 5 sampling points in each area, sampling depths of 0-10 cm, 10-20 cm, and 20-30 cm, and the diameter of the soil drill was 2.5 cm. 200 ml of soil was taken each time, and the shallow plate method was used to separate the nematodes, which were killed with warm water at 60°C and fixed with formaldehyde to calculate the insect population reduction rate.

[0033] During the potato harvest period, sampling was carried out at 5 points in each plot of the experimental area, and 10 potato tubers were taken at each point. Each tuber was cross-cut and graded according to the disease severity of its cross section. Level 0: No symptoms (no chaff and cracks); Grade 1: The diseased area accounts for less than 25% of the cross-section; Grade 2: The diseased area accounts for 25% to 50% of the cross-section; Grade 3: The diseased area accounts for 50% to 75% of the cross-section; Level 4: The diseased area accounts for more than 75% of the cross section. Record the number of tubers at each level and calculate the disease index, incidence rate and control effect.

[0034] The calculation formula is as follows: Pest reduction rate = (number of insects before treatment - number of insects after treatment) / number of insects before treatment × 100% Disease index = [∑ (disease level value × number of tubers of corresponding level)] / (total number of tubers surveyed × highest disease level value) × 100 Control effect = (disease index in control area - number of diseases in treatment area) / disease index in control area × 100% 5. Experimental results and statistics The control effects of 50% and 20% soluble solutions of Gnaphalium truncatum extract on potato stem nematodes were determined, and the results are shown in Table 3.

[0035] Table 3 Control effect of 2 kinds of nematicide preparations of Gnaphalium spp. on potato stem nematodes

[0036] Note: The data in Table 3 are the average values ​​of 3 repetitions; in the "Protective Effect" column, the same letters after the values ​​in the same column mean that there is no significant difference at the α=0.05 level (DMRT method).

[0037] As shown in Table 3, in terms of insect population reduction rate and control effect, the two preparations of the extract of Gastrodia elata have good control effects on potato stem nematodes. Among them, the control effects of the two preparations of Gastrodia elata on potato stem nematodes at 100 times and 300 times dilutions were significantly better than those of the control agent. The control effect of the 500-fold dilution on potato stem nematodes was equivalent to that of the control agent.

Claims

1. Use of a Gnetum macrophylla extract for preparing a nematicide, wherein the Gnetum macrophylla extract is an organic solvent extract of Gnetum macrophylla, and the nematode is Ditylenchus potatoein.

2. The use according to claim 1, characterized in that: The Gnaphalium macrophyllum extract is a methanol extract of Gnaphalium macrophyllum.

3. The use according to claim 1, characterized in that: The preparation method of the Gnaphalium macrophylla extract comprises: A. Grind the large-leaved Gnaphalium wilfordii into pieces of 1-5 mm to obtain a coarsely ground product; B. The coarsely ground product obtained in step A is extracted with an organic solvent under ultrasonic conditions at 25-35° C. for 0.5-1 hour; the obtained extract is concentrated by vacuum concentration to obtain the Gnaphalium macrophylla extract.

4. A nematicide from Gnetum chinense, characterized in that: The nematode is potato stem nematode, the active component of the nematicide is organic solvent extract of Gnetum macrophylla, and the preparation form of the nematicide is soluble liquid.

5. The nematicide of Gnetum chinense according to claim 4, characterized in that The nematicide contains 20% to 50% of the Gnetum chinense extract; the Gnetum chinense extract is prepared by extracting 1kg of dried Gnetum chinense with 5 to 10kg of organic solvent, and concentrating the extract to 1kg.

6. A nematicide of Gnetum chinense, wherein the nematode is Ditylenchus potatoein, characterized in that: The raw materials for preparing the nematicide include the following components in percentage by mass: 20% to 50% of Gnaphalium macrophyllum extract, 5% to 40% of organic solvent, 5% to 40% of surfactant, and 5% to 10% of antifreeze agent, and the sum of the percentages by mass of the above components is 100%; The extract of Gnetum chinense is prepared by extracting 1 kg of dried Gnetum chinense with 5 to 10 kg of organic solvent, and concentrating the extract to 1 kg; The organic solvent is one or a mixture of two or more of ethyl acetate, cyclohexanone, methyl oleate, ethanol, methanol, acetone, dimethylformamide, ethylbenzene and xylene; The surfactant is one or a mixture of two or more of alkylbenzene sulfonates, alkylphenol polyoxyethylene ethers, phenethylphenol polyoxyethylene ethers, phenethylphenol polyoxyethylene ether polyoxypropylene ethers and similar substances, adducts of castor oil and ethylene oxide, and arylalkylphenol polyoxyethylene ether formaldehyde condensates; The antifreeze agent is ethylene glycol, polyethylene glycol, glycerol, propylene glycol or urea.

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