Application of motherwort herb extract in preparation of nematicide

Abstract

The invention discloses an application of a motherwort herb extract in preparing a nematicide. The motherwort herb extract can be used for preventing and treating Meloidogyne incognita on crops such as tomatoes, pumpkins and cucumbers, and also can be used for preventing and treating Meloidogyne incognita on crops such as tomatoes, pumpkins and cucumbers. The compound disclosed by the invention can be used for preventing and controlling the potato stem nematodes (White) Chitwood, can also be used for preventing and controlling the potato stem nematodes on crops such as potatoes, sweet potatoes and the like, has a good nematode killing effect, and is safe to the environment, human, livestock, natural enemies of pests and other beneficial organisms.

Description

Technical Field

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

[0002] Ditylenchus destructor Thorne, belonging to the order Pseudocranoides, family Pseudocranidae, genus Ditylenchus, is an important parasitic nematode, and its host plants are potatoes and sweet potatoes. Ditylenchus destructor infects potato stems and vines. The early symptoms of the infection are relatively hidden, with white spots appearing in the pith. Later, as the infection of potato rot increases, the pith becomes brown and dry, and the above-ground potato stems and vines are cracked and even have dark brown stripes. When Ditylenchus destructor infects leaves, it can cause partial necrosis of leaf tissue, curling and fading of leaves, and even leaf shedding in severe cases, causing serious economic losses to the production of potatoes and sweet potatoes.

[0003] The southern root-knot nematode, Meloidogyne incognita (Kofold & White) Chitwood, belongs to the order Meloidogyne, family Heterodera, genus Meloidogyne, and is an important parasitic nematode with a wide distribution range. Its life cycle includes three stages: egg, larvae, and adult. In farmland, root-knot nematodes mainly overwinter in the soil as eggs and second-instar larvae. Even in the absence of a host, root-knot nematodes can survive in the soil for up to 3 years. When the temperature warms up to about 15°C in the spring of the second year, the nematode eggs begin to hatch, and the larvae of the root-knot nematodes can survive in soil with a thickness of 3-25 cm, with the majority distributed in soil with a thickness of 5-15 cm. Each female root-knot nematode can lay 200-700 eggs and has a very strong reproductive capacity. Under suitable climatic conditions in the field, a reproductive cycle can be completed in more than 20 days. According to statistics, the southern root-knot nematode causes economic losses of about 50 billion yuan to different industries around the world each year, seriously threatening the healthy growth of crops such as agriculture and horticulture. Summary of the invention

[0004] Based on the research findings of the inventors, the present invention provides the use of a Leonurus japonicus extract for preparing a nematicide, wherein the Leonurus japonicus extract is an organic solvent extract of Leonurus japonicus, and the nematode is a potato nematode or an incognita root-knot nematode.

[0005] An optional solution is that the Leonurus japonicus extract is Leonurus japonicus methanol extract.

[0006] An optional solution is that the preparation method of the Leonurus japonicus extract comprises:

[0007] A. Crush the whole plant of Leonurus japonicus into 1-5 mm to obtain a coarsely ground product;

[0008] 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 h; the obtained extract is vacuum concentrated to obtain the motherwort extract.

[0009] The present invention also provides a motherwort nematode agent, wherein the nematode is potato nematode or southern root-knot nematode, and the active component of the nematode agent is an organic solvent extract of motherwort; the preparation form of the nematode agent is a microemulsion.

[0010] An optional solution is that the mass percentage of the motherwort extract in the nematicide preparation is 5% to 50%; the motherwort extract is an extract obtained by extracting 1 kg of dried motherwort with 5 to 10 kg of organic solvent and concentrating the extract to 1 kg.

[0011] An optional solution is that the nematode is potato nematode or southern root-knot nematode, and the raw materials for preparing the nematicide include the following components in percentage by mass:

[0012] Motherwort extract: 5% to 50%, organic solvent: 5% to 30%, emulsifier: 10% to 30%, antifreeze: 5% to 10%, water: less than or equal to 55%; the sum of the mass percentages of each component is 100%;

[0013] The motherwort extract is obtained by extracting 1 kg of dried motherwort with 5 to 10 kg of organic solvent, and concentrating the extract to 1 kg;

[0014] The organic solvent is one or a mixture of two or more of ethyl acetate, cyclohexanone, methyl oleate, ethanol, methanol, dimethylformamide and isopropanol;

[0015] The emulsifier is one or a mixture of two or more of alkyl polyglycosides, glucose amides, alcohol ether carboxylates, monoalkyl phosphonates, alkyl benzene 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;

[0016] The antifreeze agent is ethylene glycol, polyethylene glycol, propylene glycol, glycerol or urea.

[0017] The organic extract of Leonurus japonicus has significant nematicidal activity. It can be used not only for the control of southern root-knot nematode M. incognita on crops such as tomatoes, pumpkins and cucumbers, but also for the control of potato stem nematode D. destructor on crops such as potatoes and sweet potatoes. It is safe for humans, livestock, natural enemies of pests and other beneficial organisms, and has good environmental compatibility. As a biogenic pesticide, it has no residual toxicity after use. DETAILED DESCRIPTION

[0018] Unless otherwise specified, the scientific and technical terms used herein are understood according to the knowledge of ordinary technicians in the relevant fields.

[0019] Motherwort (Leonurus japonicus Houtt.) is a herbaceous plant of the Lamiaceae family and the genus Leonurus. Motherwort grows in the mountains, riverbanks, and wet places beside streams. It is widely distributed throughout the country. Fresh products are harvested from the seedling stage in spring to the early summer before flowering; dried products are harvested in summer when the stems and leaves are lush and the flowers have not yet bloomed or have just bloomed, and then dried in the sun, or cut into sections and dried in the sun. It is widely distributed throughout the country. It has the effects of promoting blood circulation and regulating menstruation, promoting diuresis and reducing swelling, and clearing away heat and detoxifying. It is used for irregular menstruation, dysmenorrhea, amenorrhea, lochia retention, edema, oliguria, sores and swelling.

[0020] The motherwort extract of the present invention is a concentrate extracted from the crushed material of the whole motherwort plant by an organic solvent, preferably methanol, i.e., an organic solvent extract of motherwort. The preferred extraction conditions are ultrasound and room temperature.

[0021] The botanical nematicide of the present invention uses the extract of Leonurus japonicus as the active substance, and a certain proportion of auxiliary agents are added for dosage form processing, so as to prepare an environmentally friendly preparation microemulsion or 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.

[0022] In order to better understand the essence of the invention, the following examples are used to explain 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, 30% motherwort extract microemulsion and 30% motherwort extract soluble liquid have good control effects on southern root-knot nematodes and potato stem nematodes.

[0023] Embodiment 1:

[0024] The extraction method of the motherwort methanol extract of this embodiment comprises:

[0025] A. Use a plant grinder to grind the whole dried motherwort into coarse powder of 1 to 5 mm.

[0026] The coarse powder obtained in step A is extracted with methanol (the mass ratio of the coarse powder to methanol is 1kg:8kg), 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 vacuum concentrated to the equivalent of 1kg.

[0027] Indoor bioassay methods and results of Leonurus japonicus methanol extract against nematodes:

[0028] The nematodes with healthy growth and uniform size were selected as the test nematodes to determine the toxicity of the Leonurus japonicus extract. 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 the drug mother solution (V3) was added, mixed evenly, and placed in a 25°C incubator. Each treatment was repeated 3 times, with 80 nematodes per repeat, and methanol treatment was used as the control. 24h and 48h after treatment, the death and survival of the 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.

[0029] 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 repeatedly with eyelashes. Those that change shape obviously after being touched are recorded as alive. Otherwise, they are recorded as dead.

[0030]

[0031]

[0032]

[0033] V = volume of nematode suspension V1 + supplementary sterile water volume V2 + volume of drug stock solution V3; V = 400 μL; V1 = 100 μL; N is set in advance in the experiment, and in this embodiment N = 100 mg DW / mL; in order to ensure the consistency of the number of treated nematodes, N0 is known, and in this embodiment N0 = 400 mg DW / mL, then V is fixed, and V2 and V3 of different treatments can generally be obtained based on this.

[0034] The toxicity of Leonurus japonicus extract to nematodes was determined by the liquid immersion method, and a toxicity curve was drawn. The results are shown in Tables 1 and 2.

[0035] Table 1 Toxic effect of methanol extract of Leonurus japonicus on two nematodes

[0036]

[0037] Table 2 Toxicity curve of the nematode killing activity of methanol extract of Leonurus japonicus

[0038]

[0039] As shown in the table above, the methanol extract of Leonurus japonicus has strong toxicity against Ditylenchus edulis and Meloidogyne incognita. The corrected mortality rates of Ditylenchus edulis and Meloidogyne incognita at 100 mg DW / mL for 48 h were 87.80% and 85.54%, respectively. 50 The LC values ​​of southern root-knot nematode at 24h and 48h were 30.07 and 33.50 mgDW / mL respectively. 50 They were 51.87 and 48.44 mgDW / mL respectively.

[0040] Embodiment 2:

[0041] This embodiment is the preparation of 30% motherwort extract microemulsion, specifically, 30kg of motherwort concentrate is dissolved in 30kg of methanol, and then 15kg of calcium dodecylbenzene sulfonate, 5kg of polyoxyethylene styrene acid ether, and 5kg of ethylene glycol are added, mixed under high-speed stirring, and heated to about 40°C; 15kg of deionized water is added dropwise under high-speed stirring, and the water dropping speed is controlled to keep the temperature at about 40°C; after the water is added dropwise, the temperature is raised to 50°C, and stirred for 1 hour to obtain 100kg of 30% motherwort extract microemulsion. The stability and appearance of the preparation meet the requirements of commercial preparations.

[0042] Embodiment 3:

[0043] This embodiment is the preparation of a 50% soluble liquid of Leonurus herb extract, specifically, 50 kg of Leonurus herb concentrate is dissolved in 20 kg of methanol, 15 kg of sodium dodecylbenzene sulfonate and 5 kg of ethylene glycol are added under stirring, and deionized water is added to make up to 100 kg, and after mixing evenly, 100 kg of soluble liquid of Leonurus herb extract can be prepared. The stability and appearance of the preparation meet the requirements of commercial preparations.

[0044] Embodiment 4:

[0045] This example shows the field efficacy test results of the motherwort extract preparation of Example 2-3 against southern root-knot nematodes.

[0046] 1. Test reagents

[0047] Motherwort extract microemulsion, the motherwort extract microemulsion in Examples 2 and 3;

[0048] 41.7% Fluopyram SC (Bayer CropScience (China) Co., Ltd. Beijing Branch)

[0049] 2. Test crops

[0050] Tomato, variety "Jingpin Maofen 802"

[0051] 3. Targets of prevention and treatment

[0052] Southern root-knot nematode (Meloidogyne incognita)

[0053] 4. Selection of test plots and test treatment

[0054] 4.1 Selection of experimental plots

[0055] This experiment was conducted in a greenhouse in Dali Modern Agricultural Park, Weinan City, Shaanxi Province. A representative tomato plot with disease was selected as the test site. The previous crop of tomatoes was planted, the southern root-knot nematode occurred evenly and severely, other diseases and pests were mild, the soil was sandy loam, the soil texture was light, the nutrient content was high, and normal fertilizer and water management was carried out.

[0056] 4.2 Experimental treatment and plot design

[0057] The test agents were 200× and 600× dilutions of Leonurus japonicus extract microemulsion; 1500× dilutions of 41.7% fluopyram suspension and blank control (water), with a total of 6 treatments. The experimental plots were arranged in random blocks, with an area of ​​25 m 2 , repeat 3 times.

[0058] 4.3 Application method

[0059] Irrigate each plot before treatment to ensure that the soil moisture content reaches 60% to 70% of the saturated water holding capacity. Rotate till the soil before applying the pesticide to a depth of 20 to 30 cm. Spray the pesticide evenly on the soil surface at a spray rate of 50 L / mu and then till the soil again to fully mix the pesticide with the soil before transplanting tomatoes. 41.7% Fluopyram suspension 1500× and clean water were used as the pesticide control and blank control, respectively, and the water and fertilizer management was the same. The temperature in the greenhouse was low during the experiment, with a maximum temperature of 30°C and a minimum temperature of 20°C. Sampling was conducted two months later.

[0060] 4.4 Survey Methods

[0061] Random sampling was adopted, 5 points were selected in each plot, 5 plants were selected in each point, the number of root knots of each tomato plant was checked according to the following standards, and the classification was recorded. The classification method is shown in Table 3 below:

[0062] Table 3 Root knot classification standards

[0063]

[0064] The control effect is calculated according to the following formula:

[0065] Root knot index (%) = {[∑(number of disease-grade plants × corresponding grade value)] / total number of plants × 9} × 100;

[0066] Control effect (%) = [(root knot index of control area - root knot index of drug-treated area) / root knot index of control area] × 100.

[0067] 5. Test results and statistics

[0068] The control effects of 30% and 50% Leonurus japonicus extract microemulsions on southern root-knot nematodes were determined, and the results are shown in Table 4.

[0069] Table 4 Control effects of two nematicides prepared from Leonurus japonicus extracts on southern root-knot nematodes

[0070]

[0071]

[0072] Note: The data in Table 4 are the average values ​​of 3 replicates; in the "Protection Effect" column, the same letter after the value in the same column means that the difference is not significant at the α=0.05 level (DMRT method). (The same as in the following table)

[0073] As shown in Table 4, the two motherwort extract preparations have good control effects on southern root-knot nematodes, and the control effect of 50% motherwort extract microemulsion diluted 200 times on southern root-knot nematodes is equivalent to that of the control agent. The control effects of other treatments are all above 75%.

[0074] Embodiment 5:

[0075] This example shows the field control effect test results of the Leonurus japonicus extract preparation of Example 2-3 on Ditylenchus edulis.

[0076] 1. Test reagents

[0077] Motherwort extract microemulsion, the motherwort extract microemulsion in Examples 2 and 3;

[0078] 1.8% avermectin emulsifiable concentrate (Jiangsu Suling Pesticide Chemical Co., Ltd.).

[0079] 2. Test crops

[0080] Potatoes, variety "Purple Flower White"

[0081] 3. Targets of prevention and treatment

[0082] Potato stem nematode (Ditylenchus destructor)

[0083] 4. Selection of test plots and test treatment

[0084] 4.1 Selection of experimental plots

[0085] This experiment was conducted in the greenhouse of Dali Modern Agricultural Park in Weinan City, 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 and high nutrient content, and normal fertilizer and water management.

[0086] 4.2 Experimental treatment and plot design

[0087] The test agents were 200× and 600× dilutions of Leonurus japonicus extract microemulsion, 1000× dilution of 1.8% avermectin emulsifiable concentrate and blank control (water), with a total of 6 treatments. The experimental plots were arranged in random blocks, with an area of ​​25 m 2 , repeat 3 times.

[0088] 4.3 Application method

[0089] Irrigate each plot before treatment to ensure that the soil moisture content reaches 60% to 70% of the saturated water holding capacity. Rotate till the soil before applying the pesticide to a depth of 20 to 30 cm. Spray the pesticide evenly on the soil surface at a spray rate of 50 L / mu and then till again to fully mix the pesticide with the soil before planting. 1.8% avermectin emulsifiable concentrate 1000× and clean water were used as the pesticide control and blank control, respectively, and the water and fertilizer management was the same. The temperature in the greenhouse was low during the experiment, with a maximum temperature of 30°C and a minimum temperature of 20°C. Samples were taken after potato harvest.

[0090] 4.4 Survey Methods

[0091] After 45 days, the "Z"-shaped sampling method was used to take samples, 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 mg of soil was taken each time, and the nematodes were separated by the shallow plate method. The nematodes were killed with warm water at 60°C, fixed with formaldehyde, and the nematode population reduction rate was calculated.

[0092] During the potato harvest period, sampling was carried out at 5 points in each plot of the experimental area. Ten potato tubers were taken at each point, and each tuber was cross-sectioned and graded according to the disease severity of the cross section:

[0093] Level 0: no symptoms (no chaff and cracks);

[0094] Grade 1: The diseased area accounts for less than 25% of the cross-section;

[0095] Grade 2: The diseased area accounts for 25% to 50% of the cross-section;

[0096] Grade 3: The diseased area accounts for 50% to 75% of the cross-section;

[0097] Level 4: The affected area accounts for more than 75% of the cross-sectional area.

[0098] Record the number of tubers at each level and calculate the disease index, incidence rate and control effect. The calculation formula is as follows:

[0099] Pest reduction rate = (pest number before treatment - pest number after treatment) / pest number before treatment × 100%;

[0100] Disease index = [∑(disease grade value × number of tubers of corresponding grade)] / (total number of tubers surveyed × highest disease grade value) × 100;

[0101] Control effect = (disease index in control area - number of diseases in treatment area) / disease index in control area

[0102] ×100%;

[0103] 5. Test results and statistics

[0104] The control effects of 30% and 50% Leonurus japonicus extract microemulsions on potato stem nematodes were determined. The results are shown in Table 5.

[0105] Table 5 Control effects of two nematicides prepared from Leonurus japonicus extracts on Ditylenchus edulis

[0106]

[0107] As shown in Table 5, the two motherwort extract preparations have good control effects on potato stem nematodes. Among them, the control effect of 50% motherwort extract microemulsion 200 times diluted solution on potato stem nematodes is significantly better than the control effect of the control agent avermectin; the control effect of 30% motherwort extract microemulsion 600 times diluted solution on potato stem nematodes is equivalent to that of the control agent.

[0108] The above description is only a preferred specific implementation manner of the present invention, and the protection scope of the present invention is not limited thereto. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. Use of a motherwort extract for preparing a nematicide, wherein the motherwort extract is an organic solvent extract of motherwort, and the nematode is a potato nematode or a southern root-knot nematode.

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

3. The use according to claim 1 or 2, characterized in that: The preparation method of the motherwort extract comprises: A. Crush the whole plant of Leonurus japonicus into 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 h; the obtained extract is vacuum concentrated to obtain the motherwort extract.

4. A motherwort nematicide, characterized in that: The nematode is potato nematode or southern root-knot nematode, the active component of the nematicide is organic solvent extract of Leonurus japonicus; the preparation form of the nematicide is microemulsion.

5. The motherwort nematicide according to claim 4, characterized in that The mass percentage of the motherwort extract in the nematicide preparation is 5% to 50%; the motherwort extract is obtained by extracting 1kg of dried motherwort with 5 to 10kg of organic solvent and concentrating the extract to 1kg.

6. A motherwort nematicide, characterized in that: The nematode is potato nematode or southern root-knot nematode, and the raw materials for preparing the nematicide include the following components in percentage by mass: Motherwort extract: 5% to 50%, organic solvent: 5% to 30%, emulsifier: 10% to 30%, antifreeze: 5% to 10%, water: less than or equal to 55%; the sum of the mass percentages of each component is 100%; The motherwort extract is obtained by extracting 1 kg of dried motherwort 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, dimethylformamide and isopropanol; The emulsifier is one or a mixture of two or more of alkyl polyglycosides, glucose amides, alcohol ether carboxylates, monoalkyl phosphonates, alkyl benzene 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, propylene glycol, glycerol or urea.

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