Acaricide made from ginger grass, its preparation method and application

Abstract

This invention discloses an acaricide using ginger grass as a raw material. The acaricide is obtained by mixing ginger grass extract with water, and the concentration of ginger grass extract in the acaricide is greater than 0.5 mg / ml. The preparation steps of the ginger grass extract include, in sequence, ingredient preparation, irradiation, concentration preparation, extract preparation, and finished product preparation. The invention also provides an application of the acaricide using ginger grass as a raw material in the control of *Tetranychus carinata*. In this application, the concentration of ginger grass extract in the acaricide is 50 mg / ml. The acaricide of this invention not only has a good effect on controlling *Tetranychus carinata*, but also shows that the pest is unlikely to develop resistance, it causes little harm to non-target organisms, has a relatively mild effect, and the raw material is abundant, thus possessing very broad development prospects.

Description

Technical Field

[0001] This invention belongs to the field of mite control technology, specifically relating to an acaricide made from ginger grass, its preparation method, and its application. Background Technology

[0002] *Micromeria biflora* Benth, a plant belonging to the genus *Micromeria* in the family Lamiaceae, is also known as small fragrant herb, small ginger grass, and small fragrant sage. It is mainly distributed in Yunnan and Guizhou provinces, possessing resource advantages and development potential. The entire plant can be used medicinally and is a commonly used herb among ethnic minorities in southwestern my country. The stem is purplish-brown. The leaves are small and densely packed, ovate, and opposite, with many fine white hairs on the stems and leaves. The volatile oil, the active ingredient of *Micromeria biflora*, has a pungent odor. This volatile oil contains components similar in aroma to ginger oil, such as nerol and geraniol, hence the name *Micromeria biflora*. The whole plant has a strong ginger aroma and a pungent taste.

[0003] The carmine spider mite (Tetranychus cinnabarinus Boisduval), belonging to the family Tetranychidae in the order Acaria, also known as the cotton red spider mite, is a major pest of crops such as melons, watermelons, cucumbers, eggplants, strawberries, and corn. It weakens plant growth, and without proper control, severely impacts the yield and quality of host plants, even leading to their death. Widely distributed in temperate regions, it is a global pest with a rapid reproduction rate and diverse host plants, causing significant agricultural losses. While chemical pesticides can offer some control, they also bring other serious side effects.

[0004] In recent years, research on plant-derived insecticides has been extensive, becoming a research hotspot both domestically and internationally. Secondary metabolites produced by plants possess specific biological activities and can serve as excellent alternatives to synthetic organic pesticides, making them a type of natural insecticide. Plant-derived insecticides are characterized by good environmental compatibility, diverse modes of action, low resistance in pests, minimal harm to non-target organisms, relatively mild efficacy, and abundant raw materials, giving them a very broad development prospect.

[0005] Most current research on ginger grass focuses on its medicinal or chemical components. For example, Zhang Qingzhi et al. (2000) studied the medicinal properties of ginger grass, finding through experiments on its plant morphology, medicinal characteristics, and physicochemical features that ginger grass has a ginger aroma. The whole plant can be used as a flavoring agent for alcoholic beverages and in medicine, possessing the effects of warming the middle jiao and strengthening the stomach, dispelling wind and cold, and preventing dysentery, showing broad application prospects in the pharmaceutical field. Pan Tianling et al. (2010) studied the DPPH free radical scavenging activity of ginger grass essential oil and extracts, showing that the extract of ginger grass has strong free radical scavenging activity, providing a scientific basis and reference for its development and application in the pharmaceutical, health product, and cosmetic industries. Ginger grass contains many chemical types, including volatile oils, terpenes, sterols, phenols or reducing compounds, polysaccharides, triterpenoids, coumarins and their glycosides, etc. However, research on plant-derived insecticides from ginger grass is currently scarce.

[0006] Currently, agricultural pest and disease control mainly relies on chemical control measures. However, long-term use of chemical pesticides leads to resistance and has serious consequences for humans and the environment. The use of chemical pesticides is increasing daily, and the types are gradually expanding. The harm and impact of chemical pesticides on human and animal health and the ecological environment are becoming increasingly prominent. Therefore, plant-derived insecticides have become a hot research topic. In recent years, there has been much research on extracting active substances from plants for acar control, such as lavender, cinnamon, patchouli, and lemongrass. This involves using active substances extracted from plants to create natural, highly selective, non-toxic, easily degradable, and less likely to induce resistance plant-derived insecticides. Currently, some plants with good pest control effects have been screened both domestically and internationally, and the extraction of their active ingredients to develop plant-derived pesticides has become a major international trend. However, research on the pest control effects of ginger grass is limited, mainly focusing on the composition and methods of extracts. There are no reports yet on the efficacy of its extracts in controlling acar pests. The development of plant-derived pesticides is currently one of the hot research areas. Ginger grass contains a variety of chemical components, and its volatile oil contains nerol and geraniol, which have a similar smell to ginger oil and a spicy taste. The visual system of the carmine spider mite is relatively degenerate, and its sense of smell is more important. The chemical substances and related characteristics produced by plants have a direct impact on the carmine spider mite. Summary of the Invention

[0007] To address the aforementioned problems, the present invention aims to provide an acaricide using ginger grass as a raw material, its preparation method, and its application. The acaricide is highly effective in controlling the red spider mite.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] An acaricide using ginger grass as a raw material, wherein the acaricide is obtained by mixing ginger grass extract with water, and the concentration of ginger grass extract in the acaricide is greater than 0.5 mg / ml.

[0010] Furthermore, the concentration of ginger extract in the acaricide is 5 mg / ml-50 mg / ml.

[0011] Furthermore, the method for preparing the acaricide includes the preparation of ginger grass extract and the formulation of the acaricide. The preparation steps of the ginger grass extract are as follows:

[0012] (1) Ingredients: Mix ginger grass powder and organic solvent in a weight ratio of 1:(5-30) to obtain a mixture for later use;

[0013] (2) Radiation: Place the mixture obtained in step (1) into a 480W microwave oven for 10 seconds. After it has cooled down sufficiently, place it into the microwave oven again for 10 seconds. Repeat this process 5 times for a total of 50 seconds. After the mixture has cooled to room temperature, filter it and take the filtrate for later use.

[0014] (3) Preparation of concentrated solution: The filtrate obtained in step (2) is concentrated, and when the solution evaporates to a viscous state, it is taken out to obtain concentrated solution for later use;

[0015] (4) Preparation of extract: Add an appropriate amount of anhydrous sodium sulfate to the concentrate obtained in step (3) for dehydration; filter the concentrate again and take the extract that passes through the sieve for later use;

[0016] (5) Preparation of finished product: Place the extract obtained in step (4) into a pre-weighed petri dish, seal it with plastic wrap and poke holes (to facilitate the evaporation of residual solvent), and obtain the finished product after the residual solvent has evaporated naturally.

[0017] The preparation steps for the acaricide are as follows:

[0018] The prepared ginger extract is mixed evenly with water to make an acaricide.

[0019] Furthermore, in step (1), the organic solvent is any one of ethyl acetate, anhydrous ethanol, and n-hexane.

[0020] Furthermore, in step (1), the organic solvent is anhydrous ethanol.

[0021] Furthermore, in step (1), the ginger herb powder and the organic solvent are mixed at a weight ratio of 1:30 to obtain a mixture.

[0022] Application of an acaricide made from ginger grass in the control of Tetranychus cinnabarinus. In this application, the concentration of ginger grass extract in the acaricide is 50 mg / ml.

[0023] This invention selects ginger grass as raw material, utilizes the special physicochemical properties of ginger grass, and uses microwave-assisted extraction to extract its effective components. After mixing the effective components with water, a plant-derived insecticide is prepared, mainly used to control carmine spider mites. This not only has a good effect on controlling carmine spider mites, but also the pests are not likely to develop resistance, it causes little damage to non-target organisms, the efficacy is relatively mild, and the raw materials are abundant, so it has a very broad development prospect. Attached Figure Description

[0024] Figure 1 A comparison chart of extraction rates of ginger grass extracted with different organic solvents and different solid-liquid ratios;

[0025] Figure 2 Comparative graph showing the toxic effects of different concentrations of ginger extract on Tetranychus cinnabarinus eggs;

[0026] Figure 3 Comparison of the toxic effects of different concentrations of ginger extract on the larvae of the spider mite;

[0027] Figure 4 Comparison of the toxic effects of different concentrations of ginger extract on adult spider mites;

[0028] Figure 5 This is a schematic diagram of the eggs, larvae, and adults of the Tetranychus cinnabarinus under a dissecting microscope. Detailed Implementation

[0029] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0030] It should be noted that the term "comprising" or any other variation is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0031] Example 1:

[0032] This embodiment provides the application of an acaricide made from ginger grass in the control of Tetranychus cinnabarinus.

[0033] The method for preparing the acaricide includes the preparation of ginger grass extract and the formulation of the acaricide. The preparation steps of the ginger grass extract are as follows:

[0034] (1) Ingredients: Mix ginger powder and anhydrous ethanol at a weight ratio of 1:30 to obtain a mixture for later use.

[0035] (2) Radiation: Place the mixture obtained in step (1) into a 480W microwave oven for 10s. After it has cooled down sufficiently, place it into the microwave oven for 10s again. Repeat this process 5 times for a total of 50s. After the mixture has cooled to room temperature, filter it and take the filtrate for later use.

[0036] (3) Preparation of concentrated solution: The filtrate obtained in step (2) is concentrated and observed to evaporate to a viscous state. The concentrated solution is then taken out for later use.

[0037] (4) Preparation of extract: Add an appropriate amount of anhydrous sodium sulfate to the concentrate obtained in step (3) for dehydration; filter the concentrate again and take the extract that passes through the sieve for later use.

[0038] (5) Preparation of finished product: Place the extract obtained in step (4) into a pre-weighed petri dish, seal it with plastic wrap and poke holes (to facilitate the evaporation of residual solvent), and obtain the finished product after the residual solvent has evaporated naturally.

[0039] The preparation steps for the acaricide are as follows:

[0040] The prepared ginger herb extract was mixed evenly with sterile water containing 1% Tween-80 (polysorbate-80) to prepare an acaricide, which was then applied to control the carmine spider mite. The concentration of ginger herb extract in the acaricide was 50 mg / ml.

[0041] Example 2:

[0042] This embodiment provides the application of an acaricide made from ginger grass in the control of Tetranychus cinnabarinus. The concentration of ginger grass extract in the acaricide is 0.5 mg / ml.

[0043] Example 3:

[0044] This embodiment provides the application of an acaricide made from ginger grass in the control of Tetranychus cinnabarinus. The concentration of ginger grass extract in the acaricide is 5 mg / ml.

[0045] Example 4:

[0046] This embodiment provides the application of an acaricide made from ginger grass in the control of Tetranychus cinnabarinus. The concentration of ginger grass extract in the acaricide is 10 mg / ml.

[0047] Example 5:

[0048] This embodiment provides the application of an acaricide made from ginger grass in the control of Tetranychus cinnabarinus. The concentration of ginger grass extract in the acaricide is 60 mg / ml.

[0049] Verification experiment:

[0050] 1. Experimental materials and reagents

[0051] Experimental materials: Gingerwort was collected from the mountains of Anshun, Guizhou. After being brought back to the laboratory, the roots were removed, washed and dried, ground into fine powder and passed through a 100-mesh sieve. It was then sealed in a sealed bag for storage. The red spider mite was collected from the Anshun College Mountain Park. It was brought back to the laboratory along with its host and raised for more than three generations using the water tray method for future use.

[0052] Experimental reagents: ethyl acetate (99.5%, Guangdong Guanghua Technology Co., Ltd.), anhydrous ethanol (99.7%, Sichuan Xilong Science Co., Ltd.), n-hexane (97.0%, Tianjin Fuyu Fine Chemical Co., Ltd.), Tween-80 (Shanghai Maclean Biochemical Technology Co., Ltd.).

[0053] 2. Experimental Apparatus

[0054] 500ml beakers, funnels, conical flasks, iron stands, petri dishes, filter paper, glass rods, 100-mesh sieves, inoculation pens, plastic wrap, electronic balance with an accuracy of 0.001g (Huazhi Electronics Technology Co., Ltd.), rotary evaporator (Shanghai Lichen Bangxi Instrument Technology Co., Ltd.), pulverizer (Ruian Hanbo Electromechanical Co., Ltd.), 480W microwave oven (Guangdong Galanz Microwave Home Appliances Manufacturing Co., Ltd.), dissecting microscope (Nanjing Jiangnan Yongxin Optics Co., Ltd.), refrigerator (TCL Home Appliances Co., Ltd.), etc.

[0055] 3. Extraction experiment and comparative analysis of ginger herb.

[0056] 3.1 Extraction Experimental Method:

[0057] Take 20g of ginger herb powder and mix it with three organic solvents (ethyl acetate, anhydrous ethanol, and n-hexane) at ratios of 1:5, 1:10, 1:15, 1:20, and 1:30 in beakers to obtain 15 mixtures (each mixture containing 20g of ginger herb powder and the corresponding type and ratio of organic solvent). Place the mixture in a 480W microwave oven for 10 seconds, allow it to cool completely, and then place it in the microwave oven again for 10 seconds. Repeat this process 5 times, for a total of 50 seconds. After the mixture cools to room temperature, filter it and collect the filtrate. Concentrate the filtrate using a rotary evaporator. When the solution becomes viscous, remove it to obtain the concentrate. Add an appropriate amount of anhydrous sodium sulfate to the concentrate for dehydration. Then filter the concentrate again and collect the extract that passes through the sieve. Finally, filter the extract into a pre-weighed petri dish, seal it with plastic wrap and poke holes (to facilitate the evaporation of residual solvent). After the residual solvent has evaporated naturally, weigh it, calculate the extraction rate, and store it in a refrigerator at 2°C for later use.

[0058] 3.2 Data Recording and Processing

[0059] Record the experimental data (mass of ginger grass extract and mass of ginger grass powder). Use the formula: ginger grass extraction rate = mass of ginger grass extract / mass of ginger grass powder × 100% to calculate and process the experimental data to obtain the extraction rate of active substances of ginger grass extracted with different organic solvents.

[0060] 3.3 Comparative Analysis:

[0061] The extraction rates of active substances from ginger herb using different organic solvents are shown in Table 1. Figure 1 As shown:

[0062] Table 1 Extraction rates of ginger herb using different organic solvents and different solid-liquid ratios

[0063]

[0064] Note: The data were analyzed using Duncan's new multiple range method in SPSS 27.0 software. The data in the table are mean ± standard error. Different lowercase letters in the same column indicate a significant difference at the p=0.05 level; otherwise, the difference is not significant. Different uppercase letters in the same row indicate a significant difference at the p=0.05 level; otherwise, the difference is not significant. The same applies to the following tables.

[0065] From Table 1 and Figure 1 It can be seen that, using microwave-assisted extraction of active substances from *Gynostemma pentaphyllum* using ethyl acetate, anhydrous ethanol, and n-hexane at different solid-liquid ratios, the extraction rates of the three organic solvents varied. Anhydrous ethanol showed the best extraction effect, with the highest extraction rate of 6.49% at a solid-liquid ratio of 1:30. Next, n-hexane at a solid-liquid ratio of 1:5 achieved an extraction rate of 4.49%, followed by ethyl acetate at a solid-liquid ratio of 1:5, with an extraction rate of 4.28%. However, after the solid-liquid ratio of 1:5, ethyl acetate showed better extraction performance than n-hexane. In other words, under a solid-liquid ratio of 1:5, the extraction rates of the three organic solvents were: anhydrous ethanol > n-hexane > ethyl acetate; at solid-liquid ratios of 1:10 and beyond, the extraction rates of the three organic solvents were: anhydrous ethanol > ethyl acetate > n-hexane. Considering the overall economic benefits, this experiment adopted an anhydrous ethanol solid-liquid ratio of 1:30 for extraction. 4. Experiment and comparative analysis of the activity of *Gynostemma pentaphyllum* extract against *Tetranychus cinnabarinus*.

[0066] 4.1 Experimental method for determination:

[0067] The ginger extract was diluted to concentrations of 0.5 mg / ml, 5 mg / ml, and 50 mg / ml with sterile water containing 1% Tween-80. Thirty-five female adult spider mites, previously cultured in the laboratory, were selected under a dissecting microscope using a fine brush and placed on fresh green bean leaves with a radius of 1 cm. The mite-mite mixture was then cultured in a petri dish. To prevent escape, an appropriate amount of water was added to the petri dish, and a water gate was installed.

[0068] After the female adult mites laid their eggs, 35 eggs were selected from each tray to determine the toxicity of ginger-scented herb to the eggs of the Tetranychus cinnabarinus. The remaining eggs hatched into larvae, and 35 larvae were retained for larval toxicity testing. Another batch of eggs hatched into adult mites, and 35 of these were retained for testing. The eggs, larvae, and adult mites obtained using this method were then subjected to acaricide experiments against the three stages of the Tetranychus cinnabarinus using different concentrations of the prepared ginger-scented herbal solution.

[0069] Leaves infested with various life stages of the Tetranychus cinnabarinus were immersed in a ginger-scented herbal solution for 5 seconds using the leaf-insect infusion method, followed by blotting off excess solution with absorbent paper. The growth of the Tetranychus cinnabarinus in the culture medium was observed every 12 hours. A mite that did not move when gently touched with a fine brush was considered dead; observation continued for 72 hours. For the observation of eggs, since the number of hatchings was used to determine mortality, the number of hatchings was observed after 72 hours; unhatched eggs were considered dead. Each culture dish contained 35 mites at each stage, and each treatment was repeated three times. A control group was prepared using 1% Tween-80 pure water.

[0070] 4.2 Data Recording and Processing

[0071] Record experimental data (number of deaths, total number of insects), and use the formula: mortality rate (%) = number of deaths / total number of insects × 100%, corrected mortality rate (%) = (mortality rate of treatment group - mortality rate of control group) / (100% - mortality rate of control group) × 100%; calculate and process the experimental data to obtain the toxicity effect data of different concentrations of ginger extract on the eggs of Tetranychus cinnabarinus: mortality rate (%) and corrected mortality rate (%).

[0072] 4.3 Comparative Analysis of the Toxicity Effects of Gingerwort Extract on Tetranychus cinnabarinus

[0073] 4.3.1 The toxic effects of different concentrations of ginger herb extract on the eggs of *Tetranychus cinnabarinus* are shown in Table 2. Figure 2 As shown:

[0074] Table 2. Toxicity effects of different concentrations of ginger extract on Tetranychus cinnabarinus eggs.

[0075]

[0076] From Table 2 and Figure 2 It can be seen that in the ovicidal experiment of different concentrations of ginger grass extract on Tetranychus cinnabarinus eggs, the ovicidal effect of the insect eggs at 72 h after application and at concentrations of 0.5 mg / ml, 5 mg / ml, and 50 mg / ml was 25.26%, 48.49%, and 81.82%, respectively. The difference analysis showed that there was a significant difference in the ovicidal effect of different concentrations of the extract (P < 0.05).

[0077] 4.3.2 The toxic effects of different concentrations of ginger extract on the larvae of the spider mite are shown in Table 3. Figure 3 As shown:

[0078] Table 3. Toxicity effects of different concentrations of ginger extract on larvae of the spider mite *Tetranychus cinnabarinus*.

[0079]

[0080] From Table 3 and Figure 3 It was found that in the insecticidal experiments of different concentrations of *Gynostemma pentaphyllum* extract against *Tetranychus carinata* larvae, the killing efficacy against *Tetranychus carinata* larvae reached 31.37%, 63.72%, and 100% at 12 hours of application, with concentrations of 0.5 mg / ml, 5 mg / ml, and 50 mg / ml, respectively. At 24 hours of application, the killing efficacy against *Tetranychus carinata* larvae was [not specified in the original text]. The kill rates were 34.31%, 64.7%, and 100% at different concentrations. After 48 hours of application, the kill rates against *Tetranychus carinata* larvae were 39.58%, 67.71%, and 100%, respectively. After 72 hours of application, the kill rates against *Tetranychus carinata* larvae were 61.29%, 73.12%, and 100%, respectively. The 50 mg / ml concentration showed the best insecticidal effect, achieving 100% mortality within 12 hours. Differential analysis revealed significant differences in the larval kill rates among different concentrations (P < 0.05). When the drug concentration was 50 mg / ml, there were no significant differences between different observation times (P > 0.05); when the drug concentration was 5 mg / ml, there were significant differences between 12h and 60h, and 72h, and significant differences between 24h and 72h, but no significant differences between 36h, 48h, 60h, and 72h; when the concentration was 0.5 mg / ml, there were significant differences between 12h and 60h, and 72h, but no significant differences between 12h and 24h, 36h, and 48h, and significant differences between 72h and 24h, 36h, and 48h.

[0081] 4.3.2 The toxic effects of different concentrations of ginger extract on adult spider mites are shown in Table 4. Figure 4 As shown:

[0082] Table 4. Toxicity effects of different concentrations of ginger extract on adult Tetranychus cinnabarinus.

[0083]

[0084] From Table 4 and Figure 4It was found that in the insecticidal experiments of different concentrations of *Gynostemma pentaphyllum* extract against adult *Tetranychus carinata*, the killing efficacy against adult *Tetranychus carinata* reached 17.71%, 65.63%, and 91.67% at 12 hours of application, when the concentrations were 0.5 mg / ml, 5 mg / ml, and 50 mg / ml, respectively. At 24 hours of application, the killing efficacy against adult *Tetranychus carinata* was [not specified in the original text]. The kill rates were 30.11%, 70.97%, and 92.47% respectively. At 48 hours after application, the kill rates against adult *Tetranychus carinata* reached 40.86%, 77.42%, and 92.47% at concentrations of 0.5 mg / ml, 5 mg / ml, and 50 mg / ml, respectively. At 72 hours after application, the kill rates against adult *Tetranychus carinata* reached 70%, 82.22%, and 95.56% at concentrations of 0.5 mg / ml, 5 mg / ml, and 50 mg / ml, respectively. The insecticidal effect was best at a concentration of 50 mg / ml, with a mortality rate of 95.56% at 72 hours after application. Differential analysis showed significant differences in the killing effect on adult mites among different concentrations (P < 0.05). When the drug concentration was 50 mg / ml, there were no significant differences between different observation times (P > 0.05). When the drug concentration was 5 mg / ml, there were significant differences between 12 h and subsequent observation times, significant differences between 24 h and other observation times, significant differences between 36 h and 72 h, and no significant differences between 48 h, 60 h, and 72 h. When the drug concentration was 0.5 mg / ml, there were significant differences between 12 h and other observation times, no significant differences between 24 h, 36 h, and 48 h, but significant differences between 24 h, 36 h, and 48 h and 60 h and 72 h, and no significant difference between 60 h and 72 h.

[0085] 5. Conclusion and Discussion

[0086] This experiment compared the extraction rates of ginger grass with different material-liquid ratios using three different organic solvents to determine the optimal extraction scheme for ginger grass; and confirmed that ginger grass extract can achieve a control effect against spider mites.

[0087] This experimental study used microwave-assisted extraction to extract active substances from ginger herb using three different organic solvents at varying solid-liquid ratios. The results showed that the extraction rates of the three organic solvents—ethyl acetate, anhydrous ethanol, and n-hexane—were in the order of anhydrous ethanol > ethyl acetate > n-hexane, with significant differences. Among the different solid-liquid ratios of anhydrous ethanol, the 1:30 ratio yielded the highest extraction rate, 6.49%. Therefore, anhydrous ethanol achieved the highest extraction rate and best extraction effect at a solid-liquid ratio of 1:30. Specific experimental data are shown in Table 1 and... Figure 1 .

[0088] The toxicity of the active substances in *Gynostemma pentaphyllum* against eggs, larvae, and adults of *Tetranychus cinnabarinus* was verified using the leaf-infusion method. The results showed that *Gynostemma pentaphyllum* extract was effective in controlling *Tetranychus cinnabarinus*.

[0089] At a concentration of 50 mg / ml, the insecticidal effect against *Tetranychus carinata* was the best, with an adult mortality rate reaching up to 95.56%; larval mortality rate reaching up to 100%; and egg mortality rate at 72 hours was 81.82%. Differential analysis showed significant differences in insecticidal effects against adults, larvae, and eggs of *Tetranychus carinata* at different concentrations. At lower concentrations (5 mg / ml and 0.5 mg / ml), the insecticidal effect against adults and larvae of *Tetranychus carinata* varied significantly with different application times, but the effect gradually weakened as the time approached 60 hours. This indicates that the insecticidal effect against *Tetranychus carinata* is better with increasing concentrations of active substances in the herb *Gynostemma pentaphyllum* and appropriately extending the application time. The experimental data (see Tables 2, 3, and 4 for details) show that… Figure 2 (3, 4) When the concentration of the drug solution is 50 mg / ml, it has a very good control effect on different growth stages of the carmine spider mite.

[0090] The scope of protection of this invention is not limited to the technical solutions disclosed in the specific embodiments. Any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of this invention shall fall within the scope of protection of this invention.

Claims

1. The application of an acaricide in the control of Tetranychus cinnabarinus, wherein the acaricide is made from Micromeria biflora Benth, and the acaricide is obtained by mixing Micromeria biflora extract with water, wherein the concentration of Micromeria biflora extract in the acaricide is greater than 0.5 mg / ml; The method for preparing the acaricide includes the preparation of ginger grass extract, and the preparation steps of the ginger grass extract are as follows: (1) Ingredients: Mix ginger grass powder with organic solvent at a weight ratio of 1:(5-30) to obtain a mixture for later use; the organic solvent is any one of ethyl acetate, anhydrous ethanol, and n-hexane; (2) Radiation: Place the mixture obtained in step (1) into a 480W microwave oven for 10s, and after it has cooled down, place it into the microwave oven for 10s again. Repeat this process 5 times for a total of 50s. After the mixture has cooled to room temperature, filter it and take the filtrate for later use. (3) Preparation of concentrated solution: The filtrate obtained in step (2) is concentrated, and when the solution evaporates to a viscous state, it is taken out to obtain concentrated solution for later use; (4) Preparation of extract: Add an appropriate amount of anhydrous sodium sulfate to the concentrate obtained in step (3) for dehydration; filter the concentrate again and take the extract that passes through the sieve for later use; (5) Preparation of finished product: Place the extract obtained in step (4) into a pre-weighed petri dish, seal it with plastic wrap and poke holes, and wait for the residual solvent to evaporate naturally to obtain the finished product.

2. The application according to claim 1, characterized in that: The concentration of ginger extract in the acaricide is 5 mg / ml-50 mg / ml.

3. The application according to claim 1, characterized in that: In step (1), the organic solvent is anhydrous ethanol.

4. The application according to claim 3, characterized in that: In step (1), the ginger herb powder and organic solvent are mixed at a weight ratio of 1:30 to obtain a mixture.

5. In the application according to claim 3, the concentration of ginger extract in the acaricide is 50 mg / ml.

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