A repellent containing longleaf menthone and its application

Abstract

This invention provides a repellent containing longleaf menthone and its application, comprising, by mass ratio: 5%–20% longleaf menthone, 10%–20% walnut oil, 10%–20% soybean lecithin, 5%–15% stearic acid, 1%–10% trimyristic acid glyceride, 0.1%–1% poloxamer 1880, with the balance being water. This invention also provides the application of the repellent in repelling fruit flies. Experiments have demonstrated that longleaf menthone has a significant repellent effect on *Drosophila melanogaster* and *Drosophila spp.* The fruit fly repellent provided by this invention leaves no residual toxicity after application, is easily degradable, pollution-free, safe for humans and animals, does not harm non-target organisms, and does not damage the ecosystem.

Description

Technical Field

[0001] This invention belongs to the field of pest control technology and relates to a repellent, specifically a repellent containing longleaf menthone and its application. Background Technology

[0002] The spotted-winged fruit fly and the black-bellied fruit fly are insects belonging to the genus *Drosophila* in the family Drosophilaceae of the order Diptera. They feed on decaying fruit and plant matter, and have a wide host range, with known hosts including more than 60 kinds of fruits from 18 families, such as bananas, kiwifruit, persimmons, figs, strawberries, cherries, plums, nectarines, pears, blackberries, raspberries, blueberries, and grapes. Fruit flies typically lay their eggs under the peel of ripe fruit. After hatching, the larvae feed, causing the fruit to soften, rot, and fall off. Furthermore, the feeding sites of fruit fly larvae are prone to fungal and bacterial contamination, leading to juice leakage, soft and rotten flesh, further reducing fruit quality and yield. This severely impacts the fresh sale and processing of fruit, hindering the steady development of the fruit industry.

[0003] In addition, the ovipositor of the female spotted-winged fruit fly is hard and serrated, which allows it to lay eggs directly inside mature or nearly mature fruit, while the black-bellied fruit fly can only lay eggs in mature or rotten fruit. Therefore, the damage caused by the spotted-winged fruit fly is more serious than that caused by the black-bellied fruit fly.

[0004] Blueberries (Vaccinium spp.) are perennial shrubby berry-bearing trees belonging to the genus Vaccinium in the family Ericaceae. Their fruit has a unique flavor and nutritional value, enhancing human immunity. Furthermore, they possess health benefits such as anti-cancer properties, softening blood vessels, and relieving eye fatigue. The Food and Agriculture Organization of the United Nations has listed them as one of the five healthiest foods for humans, earning them the title of "golden berry." Due to their significant market advantages and economic benefits, blueberry cultivation in my country has developed rapidly in recent years, with a substantial increase in planting area. Currently, more than 20 provinces across the country cultivate blueberries, with Guizhou, Shandong, Liaoning, Sichuan, and Anhui having the largest planting areas. However, with the increase in blueberry planting area and tree age, pests have become more frequent, leading to a decline in blueberry yield and quality, and this trend is worsening year by year. Currently, fruit flies are the most serious pest in blueberry production. Moreover, fruit flies spread very quickly, and the damage they cause is almost devastating; therefore, controlling fruit flies is an urgent and crucial task for the blueberry industry.

[0005] The existing technology (Wang Zhaoguo, Yang Xue, Yu Shuai, Huang Yubing, Jin Jun, Li. Study on the effects of six plant essential oils on the behavior of Drosophila melanogaster and their active ingredients [J]. Plant Protection, 2021, 47(05): 204-209.) studied the effects of six different plant essential oils on the behavior of Drosophila melanogaster. The results showed that all six plant essential oils exhibited certain repellent activity against Drosophila melanogaster, with the order of activity being: peppermint > onion > leek > rhubarb > shallot > chili pepper. It was also found that longleaf menthone showed good repellency against Drosophila melanogaster at a concentration of 3.9 mg / L. However, this existing technology only proved the repellent effect of longleaf menthone on Drosophila melanogaster from the perspective of macroscopic behavior of the fruit fly, without delving into its repellent mechanism, and without providing a universally applicable and operable formulation and its preparation.

[0006] Based on the shortcomings of existing technologies, the inventors of this patent application have conducted in-depth research and developed a repellent with longleaf menthone as the main active ingredient. This repellent can reduce the number of eggs laid by Drosophila melanogaster and Drosophila moniliformis in fruit, improve the quality and yield of fruit, and is highly efficient, non-toxic, environmentally friendly, and safe for humans and other non-target organisms. Summary of the Invention

[0007] The purpose of this invention is to provide a fruit fly repellent with longleaf menthone as the main active ingredient and its preparation method.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a repellent containing longleaf menthone, comprising, by mass ratio: 5%–20% longleaf menthone, 10%–20% walnut oil, 10%–20% soybean lecithin, 5%–15% stearic acid, 1%–10% trimyristic acid glyceride, 0.1%–1% poloxamer 188, with the balance being water; further, the repellent provided by the present invention comprises, by mass ratio: 15% longleaf menthone, 10% walnut oil, 20% soybean lecithin, 10% stearic acid, 10% trimyristic acid glyceride, 1% poloxamer 188, and 34% water. Walnut oil, soybean lecithin, stearic acid, and trimyristic acid glyceride are auxiliary materials for solid liposomes, and poloxamer 188 is a surfactant.

[0009] Specifically, the method for preparing the fruit fly repellent is as follows: longleaf menthone, walnut oil, soybean lecithin, stearic acid, and trimyristic acid glyceride are mixed, stirred, and heated to 70°C; mixed with a poloxamer 188 aqueous solution heated to 70°C; emulsified under high pressure to form an O / W emulsion; and cooled to room temperature under stirring to obtain the repellent.

[0010] Furthermore, this invention also claims protection for the application of the repellent in repelling fruit flies; the fruit flies include *Drosophila melanogaster* and *Drosophila spp.*; the repellent is used to repel *Drosophila melanogaster* and *Drosophila spp.* in blueberry fields. Specifically, during the blueberry ripening period, the repellent is diluted with water and sprayed onto the blueberry plants once every two weeks.

[0011] This invention demonstrates through experiments that longleaf menthone achieves repulsion against *Drosophila melanogaster* and *Drosophila spp.* by regulating changes in the antennal potential of these two flies. Therefore, this invention also claims protection for a method of repelling fruit flies, which involves applying longleaf menthone to fruit flies, whereby the longleaf menthone regulates changes in the antennal potential of the fruit flies to achieve repulsion, wherein the fruit flies include *Drosophila melanogaster* and *Drosophila spp.*; and the application of longleaf menthone in fruit fly repulsion by regulating changes in the antennal potential of fruit flies.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] (1) Menthone is found in various plant essential oils and is a compound with a strong and unique aroma. Experiments have shown that menthone repels fruit flies by regulating the antennal potential of Drosophila melanogaster and Drosophila moniliformis. Menthone has a significant repellent effect on Drosophila melanogaster and Drosophila moniliformis. The repellent provided by this invention can reduce the egg production of Drosophila melanogaster and Drosophila moniliformis in fruit, thereby improving the quality and yield of fruit.

[0014] (2) The repellent described in this invention uses long-leaf menthone as the main active substance. It is prepared into a solid liposome preparation with sustained-release function by adding esters and poloxamer 188. The preparation improves the utilization rate of the drug. The raw materials are readily available, the cost is low, the efficiency is high, and there are no toxic side effects on the human body.

[0015] (3) The repellent described in this invention is highly efficient, has no residual toxicity, is easily degradable, and is pollution-free. It is safe for humans and other non-target organisms and does not damage the ecosystem. Specific Implementation

[0016] The technical solution of the present invention will be described below with reference to the embodiments. However, the present invention is not limited to the following embodiments.

[0017] Unless otherwise specified, the experimental and detection methods in the following embodiments are conventional methods; the reagents and materials mentioned are commercially available unless otherwise specified; and the index data are measured using conventional methods unless otherwise specified.

[0018] Example 1

[0019] This embodiment provides a method for preparing a fruit fly repellent containing longleaf menthone.

[0020] 1. Raw materials and proportions

[0021]

[0022] 2. Preparation steps

[0023] 2.1 Heating: The above three groups of preparations were processed separately. All raw materials in each group except poloxamer 188 and water were mixed and stirred, and then slowly heated to 70°C using a heating mantle.

[0024] 2.2 Emulsification: Pour the heated mixture from the previous step into the corresponding group's 70°C aqueous solution of poloxamer 188, and circulate and emulsify it 3 times (1000 bar) using a high-pressure homogenizer to form an O / W emulsion;

[0025] 2.3 Cooling: Stir the O / W emulsion obtained in the previous step and slowly cool it to room temperature to prepare three groups of sustained-release solid liposome formulations of long-leaf menthone with different concentrations, which are labeled as 1#, 2# and 3#, respectively, and stored for later use.

[0026] Example 2

[0027] This embodiment provides a test experiment on the effect of longleaf menthone on the antennal potential (EAG) values ​​of Drosophila melanogaster and Drosophila spp.

[0028] To aid pollination or avoid insect damage, plants produce essential oils with distinctive aromas through secondary metabolism to attract or repel insects. Essential oils are primarily composed of alcohols, aldehydes, ketones, esters, terpenes, or aromatic substances, and these compounds exhibit different behavioral tendencies in different insects. Compounds often regulate insect behavior through multiple pathways. The insect's sensory system ultimately converts the received compound stimuli into electrical signals and transmits them to the brain, which is one of the important pathways through which insect behavior is regulated by compounds. Therefore, changes in the antennal potential (EAG) value of insects can reflect the degree to which they are regulated by compounds.

[0029] 1. EAG Measurement Method

[0030] The heads of male and female *Drosophila melanogaster* and *Drosophila spp.* were severed along the neck using a scalpel. A glass electrode of an antennal potentiometer was inserted into the eye of the fly, and another glass electrode was connected to the tip of the antenna. A 1 mg / mL solution of longleaf menthone was prepared in hexane. For the measurement, 10 μL of the longleaf menthone hexane solution was added dropwise onto a filter paper strip (3 mm × 40 mm). After the solvent evaporated, the filter paper strip was placed in a glass Pasteur tube. After equilibration for 30 seconds, the potential change was measured and observed, with hexane serving as a control group. The stimulation time was set to 0.3 s, the stimulation interval to 30 s, the stimulation gas flow rate to 40 mL / min, and stimulation was repeated 10 times, with 3 repetitions. The relative EAG value was calculated using the following formula.

[0031]

[0032] 2. EAG Test Results

[0033] The effects of longleaf menthone on the antennal potential values ​​of Drosophila melanogaster and Drosophila moniliformis are shown in Table 1.

[0034] Table 1. Effects of longleaf menthone on EAG of Drosophila melanogaster and Drosophila spp.

[0035]

[0036] Table 1 shows that longleaf menthone significantly altered the antennal potential (EAG) values ​​of *Drosophila melanogaster* and *Drosophila spp.* The relative EAG values ​​of male *Drosophila melanogaster* and female *Drosophila spp.* were higher, at 1038.08% and 967.52%, respectively. The relative EAG values ​​of the two female *Drosophila spp.* were relatively close, at 963.62% and 934.38%, respectively. These results indicate that regulating the changes in antennal potential in *Drosophila melanogaster* and *Drosophila spp.* is one of the reasons why longleaf menthone repels *Drosophila melanogaster*.

[0037] Example 3

[0038] This embodiment provides an indoor repellency activity test of longleaf menthone against Drosophila melanogaster and Drosophila speciosa.

[0039] 1. Avoid activity testing methods

[0040] Enclosure method: Six groups of experiments were set up, with three replicates per group. 200 fruit flies were placed in a 25×25×25cm mesh cage and starved for 1 hour. Longleaf menthol was prepared into solutions with concentrations of 200, 100, 50, 25, and 12.5 mg / L using acetone. 100 μL of each of the five different concentrations was added to a 2cm×2cm banana slice to form five treatment groups. The control group received only an equal volume of acetone solution. Both treatment and control groups were simultaneously placed in the fruit fly cage. The number of fruit flies in each group was recorded 10 minutes after placement. The flies were then dispersed, and the count was recorded again after 10 minutes. This process was repeated three times, and the average number of flies was used to calculate the avoidance rate.

[0041]

[0042] 2. Avoid using activity test results

[0043] The results of the repellent activity tests of acetone solutions of different concentrations of longleaf menthone on Drosophila melanogaster and Drosophila moniliformis are shown in Table 2.

[0044] Table 2. Repellent activity of different concentrations of longleaf menthone against Drosophila melanogaster and Drosophila spp.

[0045]

[0046]

[0047] As shown in Table 2, the repellency rate decreased with decreasing concentration. When the concentration was 12.5 mg / L, the repellency rate for both fruit flies was less than 50%. The highest repellency rates were observed for both fruit flies at 200 mg / L of menthone, at 96.37% and 90.81%, respectively.

[0048] Example 4

[0049] This embodiment provides a field test experiment on the repellent activity of the repellent described in this invention against Drosophila melanogaster and Drosophila speciosus.

[0050] 1. Test conditions

[0051] 1.1 Experimental site: Blueberry plantation in Bailong Village, Huaxi District, Guiyang City, Guizhou Province;

[0052] 1.2 Test period: June to August 2022;

[0053] 1.3 Test reagent: The repellent prepared in Example 1.

[0054] 2. Test Methods

[0055] Spraying method: Four groups of experiments were set up, with three replicates in each group. During the blueberry ripening stage (June to August 2022), appropriate amounts of the three repellents prepared in Example 1 were taken and diluted 50 times with distilled water. Twelve blueberry trees of uniform growth were selected and divided into four groups: three experimental groups and one control group. 300 mL of the prepared solution was sprayed onto the corresponding blueberry trees in the experimental groups using a sprayer, ensuring that every leaf on every tree was sprayed. Spraying was carried out once every half month. From the second application onwards, the fruit was harvested before application, and the number of fruits was counted. The three blueberry trees in the control group were sprayed with the same dose of distilled water, and the other treatments were the same as those in the experimental groups.

[0056] Investigation Method: Fruit samples were taken at harvest. Twenty fruits were marked in each of the five directions (east, west, south, north, and center) of each tree, for a total of 100 fruits. The insect-infested fruit rate was calculated, and the repellent efficacy was determined by the average of each group. Before application, the number of insect-infested fruits in each treatment was zero.

[0057]

[0058] 3. Test Results

[0059] The field control efficacy test results of the repellent described in this invention against Drosophila melanogaster and Drosophila moniliformis are shown in Table 3.

[0060] Table 3. Field control efficacy of the repellent described in this invention against Drosophila melanogaster and Drosophila spp.

[0061]

[0062] As shown in Table 3, the three repellents prepared by the method provided in this invention have good control effects on both Drosophila melanogaster and Drosophila spp. in the field, with better control effects on Drosophila melanogaster than on Drosophila spp. Furthermore, the control effect improves with increasing application frequency. After five applications, the control effect of the three repellent formulations on both Drosophila species reached over 80%, indicating that the repellents provided in this invention have good control effects on both Drosophila melanogaster and Drosophila spp. within the formulation range described in this invention.

[0063] Example 5

[0064] This embodiment provides a verification test demonstrating that the repellent described in this invention has a sustained-release function.

[0065] 1. Experimental conditions and methods

[0066] 1.1 Test reagents: The repellent prepared in Example 1 and acetone solutions of different concentrations of longleaf menthone;

[0067] 1.2 Test period: June to July 2022.

[0068] 2. Test Methods

[0069] The envelopment method was performed in the same manner as in Example 3. The sustained-release effect of the reagent was tested at 3-day intervals, for a total of 5 tests. Six groups of reagents were prepared, including 1%, 5%, and 10% concentrations of longleaf menthol prepared with acetone, and the three groups of repellents prepared in Example 1.

[0070] 3. Test Results

[0071] The sustained-release effect of the repellent described in this invention is shown in Table 4.

[0072] Table 4. The sustained-release effect of the repellent described in this invention.

[0073]

[0074]

[0075] As shown in Table 4, the activity of longleaf menthone dissolved in acetone dropped to a very low level after 6 days, while the liposome formulation of this patent still maintained moderate repellent activity after 15 days, proving that the repellent provided by this invention has a good sustained-release effect.

[0076] As described above, the present invention can be well implemented. The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, all changes and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the present invention.

Claims

1. The application of a solid liposome repellent in the control of spotted-winged fruit flies during the blueberry ripening stage, characterized in that, The repellent component comprises, by mass ratio: 5%–20% longleaf menthone, 10%–20% walnut oil, 10%–20% soybean lecithin, 5%–15% stearic acid, 1%–10% trimyristic acid glyceride, 0.1%–1% poloxamer 188, with the balance being water; The repellent is prepared by the following method: longleaf menthone, walnut oil, soybean lecithin, stearic acid, and trimyristic acid glyceride are mixed, stirred, and heated to 70°C; mixed with an aqueous solution of poloxamer 188 heated to 70°C; emulsified under high pressure to form an O / W emulsion; and cooled to room temperature under stirring to obtain the repellent. The repellent is sprayed during the blueberry ripening period, and the application frequency is once every half month.

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