A natural blend of plant essential oils for repelling rove beetles and its applications

Abstract

This invention discloses a natural mixed plant essential oil for repelling rove beetles and its applications. The invention utilizes cinnamon leaf essential oil and borneol leaf essential oil, as well as their mixture, for repelling, fumigating, and contact killing of rove beetles. It was found that the mixture of cinnamon leaf essential oil and borneol leaf essential oil has a synergistic effect in repelling rove beetles. The optimal repellent effect is achieved when 25% cinnamon leaf essential oil and 25% borneol leaf essential oil are mixed at a volume ratio of 1:4-5. This invention provides new ideas and theoretical support for the development of natural mixed plant essential oil repellents for rove beetles. Furthermore, natural plant essential oils are highly safe, have few toxic side effects, and have no adverse effects on human health or environmental safety.

Description

Technical Field

[0001] This invention belongs to the field of rove beetle control technology, specifically relating to a natural mixed plant essential oil for repelling rove beetles and its application. Background Technology

[0002] Trichotoxin ( Paederus fuscipes *Paederus*, also known as the blue-winged ant-shaped rove beetle or blue-waisted beetle, belongs to the genus *Paederus* of the family Staphylinidae in the order Coleoptera. It is commonly distributed worldwide except for Antarctica, and is prevalent in southern my country. Adult *Paederus* are 6.5–7 mm long, with a narrow, elongated body. The head and the last two abdominal segments are black, while the pronotum and base of the abdomen are brownish-yellow. The elytra have a bluish metallic sheen. The male has a notched eighth abdominal plate, while the female's is blunt and rounded.

[0003] The rove beetle is found in very high densities and is highly mobile in fields. Due to its body fluid being rich in a highly acidic venom, it is often called a "walking sulfuric acid." Rove beetles primarily inhabit damp habitats such as freshwater lakeshores, marshes, river floodplains, thickets, and weeds along fields and ditches of various crops including rice, wheat, cotton, and corn. With urbanization and increased urban green space, the once rare rove beetle population in cities is growing. Because people are unaware of the dangers posed by rove beetles, there are frequent incidents of people accidentally swatting them, resulting in injury from the highly acidic venom and disrupting their lives.

[0004] Research on the control of the rove beetle is limited. Current control methods primarily rely on broad-spectrum insecticides with limited specificity. However, common insecticides are ineffective against the beetle, and broad-spectrum chemical insecticides have adverse effects on human health and the environment. Natural plant essential oils, on the other hand, are highly safe with minimal toxicity and show great potential for insect repellency and control. Therefore, developing products related to the control of the rove beetle using natural plant essential oils is of practical significance. Summary of the Invention

[0005] To explore safer and more effective formulations for controlling *Rove beetle*, this invention investigated the repellent, fumigation, and contact-killing activities of different concentrations of cinnamon leaf oil and borneol leaf oil against *Rove beetle*. This provides a theoretical basis for developing natural mixed plant essential oil formulations for controlling *Rove beetle*, and is hoped to provide a solid theoretical foundation for the further development, application, and resistance prevention of cinnamon and borneol leaf oils.

[0006] The first objective of this invention is to provide a mixed plant essential oil for repelling rove beetles, containing cinnamon leaf essential oil and borneol leaf essential oil as active ingredients.

[0007] Preferably, the volume ratio of cinnamon leaf essential oil to laurel leaf essential oil is 4~5:1.

[0008] Preferably, the cinnamon leaf essential oil content in the mixed plant essential oil is 20%~20.83% by volume, and the laurel leaf essential oil content in the mixed plant essential oil is 4.17%~5% by volume.

[0009] Preferably, the cinnamon leaf essential oil content in the blended plant essential oil is 20% by volume, and the laurel leaf essential oil content in the blended plant essential oil is 5% by volume.

[0010] A second objective of this invention is to provide a product for repelling rove beetles prepared using the aforementioned blend of plant essential oils.

[0011] A third objective of this invention is to provide the application of the aforementioned blend of plant essential oils in repelling rove beetles.

[0012] A fourth objective of this invention is to provide the application of the aforementioned mixed plant essential oil in the preparation of products that repel rove beetles.

[0013] The beneficial effects of this invention are:

[0014] The rove beetle, known as the "walking sulfuric acid" due to its highly acidic venom, is increasingly appearing in people's living environments as urban greening efforts increase, posing a significant threat to human health. This invention utilizes cinnamon leaf essential oil and laurel leaf essential oil to prepare a mixed plant essential oil, which exhibits excellent repellency against the rove beetle. When 25% cinnamon leaf essential oil and 25% laurel leaf essential oil are mixed at a 1:1 volume ratio, the repellency rate reaches 100% after 1 hour, while the repellency rate of 25% cinnamon leaf essential oil alone is only 80% after 1 hour. Furthermore, when the volume ratio of 25% cinnamon leaf essential oil to 25% laurel leaf essential oil is 4-5:1, the repellency rate remains 100% after 8 hours, demonstrating excellent repellency. The essential oils used in this invention are extracted from cinnamon leaves and borneol leaves, which have the advantages of safe source, no toxic side effects, and effectiveness. They can greatly reduce the safety problems and environmental pollution problems caused by chemical agents, and are easy to promote and apply. Attached Figure Description

[0015] Figure 1 This is the experimental procedure for the research and development and activity determination of natural mixed plant essential oils for the prevention and control of rove beetles.

[0016] Figure 2 The study investigated the changes in the repellency rate of different concentrations of cinnamon leaf essential oil against Rove beetles.

[0017] Figure 3 The study investigated the changes in the repellency rate of different concentrations of borneol leaf essential oil against rove beetles.

[0018] Figure 4 The study investigated the changes in the repellency rate of blended essential oils with different mixing ratios against Rove beetles.

[0019] Figure 5 The changes in gripping rate of Rove beetles after fumigation with different concentrations of cinnamon leaf essential oil are shown.

[0020] Figure 6 The changes in the grasping rate of Rove beetles after fumigation with different concentrations of borneol leaf essential oil are shown.

[0021] Figure 7 The changes in the grasping rate of Rove beetles after fumigation with mixed essential oils in different proportions are shown.

[0022] Figure 8 The study investigated the contact toxicity of different concentrations of cinnamon leaf essential oil against Rove beetle.

[0023] Figure 9 The study investigated the contact toxicity of different concentrations of borneol leaf essential oil against Rove beetle.

[0024] Figure 10 The contact toxicity of blended essential oils with different mixing ratios against Rove beetles is measured. Detailed Implementation

[0025] The following embodiments are further illustrations of the present invention, but not limitations thereof.

[0026] The following is the experimental procedure for the example: Figure 1 As shown.

[0027] Example 1

[0028] 1. Rearing of the tested rove beetles

[0029] The adult rove beetles purchased from the Qushou Natural Fun Insect and Plant Museum will be kept indoors.

[0030] Following existing rearing methods (see Bong LJ, Neoh KB, Jaal Z, et al. Life tableof paederus fuscipes (Coleoptera: S taphylinidae)[J]. Journal of Medical Entomology, 2012, 49(3): 451-460.), a 600 mL plastic bottle was used as the rearing container, with moist corn leaves placed inside as the water source. Radish aphids were used as feed. The rearing conditions were a temperature of 25±0.5℃, humidity of 65±5%, and a light-dark ratio of 12 h:12 h. After one week of rearing, the aphids were ready for experiments, at which point their survival rate was relatively stable.

[0031] 2. Raw material pretreatment

[0032] Clean the fresh cinnamon leaves and borneol leaves, select leaves without spots, and use a high-speed grinder at 1400 W to grind the leaves for 15 seconds. Then place them in a beaker to obtain cinnamon leaf homogenate and borneol leaf homogenate for later use.

[0033] 3. Preparation of essential oils from cinnamon leaves and borneol leaves

[0034] Essential oils were extracted from cinnamon leaves and borneol leaves using steam distillation. The material-to-liquid ratio was 1:5 by mass. Specifically, 100 g of cinnamon leaf homogenate or borneol leaf homogenate was weighed into a material bottle, and 0.5 L (500 g) of distilled water was added to the distillation flask. A spherical condenser was connected to the flask, ensuring the oil-water mixture from the round-bottom flask flowed directly into it. The condenser was connected and cooled with a heating mantle, and the mixture was slowly heated to a gentle boil. This gentle boil was maintained for 2 hours until the oily substance in the essential oil collector stopped increasing, indicating sufficient extraction. After cooling, the oil phase was separated from the hydrosol using a separatory funnel. The oils were then centrifuged at 28°C and 5000 rpm for 5 minutes to obtain cinnamon leaf essential oil and borneol leaf essential oil, which were then ready for use.

[0035] 4. Determination of the optimal repellent activity concentration of the two essential oils

[0036] (1) Determination of the optimal repellent activity concentration of cinnamon leaf essential oil

[0037] A filter paper with a diameter of 8 cm was cut into two equal halves with a knife. One half was added with 0.5 μL of anhydrous ethanol as a control group. The other half was added with 0.5 μL of diluted cinnamon leaf essential oil ethanol solution (cinnamon leaf essential oil was diluted with anhydrous ethanol to a volume fraction of 5%, 10%, 15%, 20%, and 25%, respectively) as an experimental group. The filter paper of the control group and the experimental group were placed at room temperature. After the anhydrous ethanol had completely evaporated, the filter paper of the control group and the experimental group were carefully transferred to the same disposable petri dish with a diameter of about 9 cm.

[0038] Ten adult rove beetles (male and female) were placed in the center of a petri dish and allowed to move freely, ensuring that all factors except the experimental factors remained consistent. Five groups were set up, numbered RGQ1~RGQ5, corresponding to cinnamon leaf essential oil concentrations of 5%, 10%, 15%, 20%, and 25% (v / v), respectively. The distribution of rove beetles on filter paper in the control and experimental groups was observed at 1, 2, 4, 6, and 8 h of treatment, with each group repeated three times. After observation, the repellency rate was calculated according to Formula 1, and the repellency activity of cinnamon leaf essential oil was classified according to the criteria shown in Table 1.

[0039] Formula 1: Repellency rate (%) = (CT) / (C + T) × 100; C represents the number of Rove beetles on the filter paper of the control group, and T represents the number of Rove beetles on the filter paper of the treatment group.

[0040] Table 1 Reference Table for Classification of Repellent Activity

[0041]

[0042] The results are shown in Table 2 and Figure 2As shown, after three repellency experiments on *Rove beetle*, it was found that the repellency rate of cinnamon leaf essential oil in groups RGQ1-RGQ3 decreased to varying degrees with changes in dilution concentration and repellency time. The repellency rate of RGQ1 decreased to 80.00% after 1 hour of repellency, gradually decreased between 2 and 8 hours, and significantly decreased to 20.00% after 8 hours, indicating extremely low repellency effect and a repellency activity level of I. RGQ2 showed a decrease in repellency rate after 2 hours of repellency, gradually decreased between 2 and 6 hours, and significantly decreased to 33.33% after 8 hours, indicating extremely low repellency effect and a repellency activity level of I. RGQ3 showed a decrease in repellency rate to 93.33% after 4 hours of repellency, gradually decreased between 4 and 8 hours, and significantly decreased to 60% after 8 hours, indicating low repellency effect and a repellency activity level of II. The repellency rate of RGQ4 was [not specified in the original text]. The repellency rate only decreased after 8 hours, and the difference was not significant. The repellency rate was 93.33%, indicating excellent repellency, with a repellency activity level of V. RGQ5 also showed good repellency activity against the rove beetle, maintaining a 100% repellency rate even after 8 hours, demonstrating excellent repellency, with a repellency activity level of V. Based on the experimental results, 25% (v / v) cinnamon leaf essential oil (RGQ5) will be selected for subsequent experiments.

[0043] Table 2 Results of determination of optimal repellent activity concentration of cinnamon leaf essential oil

[0044]

[0045] Note: The data in the table were analyzed using GraphPad 10.4 software for one-way ANOVA (P<0.05). Different letters indicate significant differences between different time points within the same experimental group.

[0046] (2) Determination of the optimal repellent activity concentration of camphor leaf essential oil

[0047] A filter paper with a diameter of 8 cm was cut into two equal halves with a knife. One half was added with 0.5 μL of anhydrous ethanol as a control group. The other half was added with 0.5 μL of diluted eucalyptus leaf essential oil ethanol solution (eucalyptus leaf essential oil was diluted with anhydrous ethanol to a volume fraction of 5%, 10%, 15%, 20%, and 25%, respectively) as an experimental group. The filter paper of the control group and the experimental group were placed at room temperature. After the anhydrous ethanol had completely evaporated, the filter paper of the control group and the experimental group were carefully transferred to the same disposable petri dish with a diameter of about 9 cm.

[0048] Ten adult rove beetles (male and female) were placed in the center of a petri dish and allowed to move freely, ensuring that all factors except the experimental factors remained consistent. Five groups were set up, numbered MPQ1 to MPQ5, corresponding to concentrations of camphor leaf essential oil of 5%, 10%, 15%, 20%, and 25% (v / v), respectively. The distribution of rove beetles on filter paper in the control and experimental groups was observed at 1, 2, 4, 6, and 8 h of treatment, with each group repeated three times. After observation, the repellency rate was calculated according to Formula 1, and the repellency activity of the camphor leaf essential oil was then classified according to the criteria shown in Table 1.

[0049] Table 3. Results of determination of optimal repellent activity concentration of camphor leaf essential oil

[0050]

[0051] Note: The data in the table were analyzed using GraphPad 10.4 software for one-way ANOVA (P<0.05). Different letters indicate significant differences between different time points within the same experimental group.

[0052] The results are shown in Table 3. Figure 3 As shown, after three repellency experiments on Rove beetles, it was found that the repellency effect of the essential oils from the leaves of the basil plant in the MPQ1~MPQ5 groups on Rove beetles decreased to varying degrees with changes in concentration and repellency time. Furthermore, MPQ1 and MPQ2 showed negative repellency rates, indicating that the number of Rove beetles in the control group was less than that in the experimental group. The repellency rate of MPQ1 against Rove beetles decreased to 10.00% after 1 hour, and became negative after 2 hours. It continued to decrease from 2 to 8 hours, reaching a significant -80.00% after 8 hours, showing no repellency effect (repellency activity level 0). The repellency rate of MPQ2 decreased to 36.03% after 1 hour, continued to decrease from 2 to 8 hours, and significantly decreased to negative values ​​after 6 hours. After 8 hours, the repellency rate was -58.89%, showing no repellency effect (repellency activity level 0). The repellency rate of MPQ3 decreased to 78.52% after 1 hour, continued to decrease from 2 to 8 hours, and significantly decreased to 0.2381% after 8 hours, showing extremely low repellency effect (repellency activity level I). The repellency rate of MPQ4 began to decrease to 77.78% after 2 hours, continued to decrease from 2 to 8 hours, and reached a significant -80.00% after 8 hours. After 2 hours, the repellency rate significantly decreased to 28.89%, indicating extremely low repellency effectiveness and a repellency activity level of I. MPQ5's repellency rate decreased to 93.33% after 2 hours, and continued to decrease between 2 and 8 hours, with no significant difference. After 8 hours, the repellency rate decreased to 53.94%, indicating low repellency effectiveness and a repellency activity level of II. Based on the experimental results, a 25% (v / v) concentration of borneol leaf essential oil (i.e., MPQ5) will be selected for subsequent experiments.

[0053] (3) Determination of the optimal repellent activity ratio of blended essential oils

[0054] Based on the results of (1) the determination of the optimal repellent activity concentration of cinnamon leaf essential oil and (2) the determination of the optimal repellent activity concentration of laurel leaf essential oil, cinnamon leaf essential oil and laurel leaf essential oil with a volume fraction of 25% were selected and mixed in sequence according to the volume ratio of laurel leaf essential oil: cinnamon leaf essential oil = 1:1, 1:2, 1:3, 1:4 and 1:5 to obtain mixed essential oils with different mixing ratios, which were numbered MRQ1~MRQ5 in sequence.

[0055] Use a knife to cut an 8 cm diameter filter paper into two equal halves. Add 0.5 μL of anhydrous ethanol to one half as a control group; add 0.5 μL of a mixture of essential oils with different mixing ratios to the other half as an experimental group. Place the filter paper of the control group and the experimental group at room temperature. After the anhydrous ethanol has completely evaporated, carefully transfer the filter paper of the control group and the experimental group to the same disposable petri dish with a diameter of about 9 cm.

[0056] Ten adult rove beetles (male and female) were placed in the center of a petri dish and allowed to move freely, ensuring that all factors except the experimental factors remained consistent. The distribution of the rove beetles on the filter paper of the control and experimental groups was observed at 1, 2, 4, 6, and 8 hours after treatment, with each of MRQ1 to MRQ5 repeated three times. After observation, the repellency rate was calculated according to Formula 1, and the repellency activity of the plant essential oils was then classified according to the criteria shown in Table 1.

[0057] Table 4. Results of Determination of Optimal Repellent Activity Ratio of Blended Essential Oils

[0058]

[0059] Note: The data in the table were analyzed using GraphPad 10.4 software for one-way ANOVA (P>0.05), indicating that there were no significant differences between different time points within the same experimental group.

[0060] The results are shown in Table 4 and Figure 4As shown, after three repellency tests on Rove beetles using a blend of essential oils, it was found that the blend of essential oils had a good overall repellency effect on Rove beetles. After 6 hours of repellency, the repellency rates of MRQ1, MRQ2, and MRQ3 all decreased to varying degrees, while the repellency rates of MRQ4 and MRQ5 did not change significantly within 8 hours, and the repellency rates were all 100%. MRQ1 showed a low avoidance rate of 93.33% after 2-4 hours of avoidance, continued to decline during 4-8 hours, and reached 53.33% after 8 hours, indicating a low avoidance effect and a level II avoidance activity. MRQ2 showed a low avoidance rate of 93.33% after 2 hours of avoidance, remained unchanged during 2-6 hours, and reached 86.67% after 8 hours, indicating a good avoidance effect and a level IV avoidance activity. MRQ3 showed a decrease in avoidance rate to 86.67% after 8 hours, indicating a good avoidance effect and a level IV avoidance activity. MRQ4 and MRQ5 maintained a 100% avoidance rate after 8 hours, indicating excellent avoidance effects and a level V avoidance activity.

[0061] In summary, the results indicate that cinnamon leaf essential oil and laurel leaf essential oil have a synergistic effect in repelling rove beetles. Furthermore, when laurel leaf essential oil and cinnamon leaf essential oil are mixed at a volume ratio of 1:4-5, the repellency rate remains at 100% after 8 hours, demonstrating excellent repellency. At this point, the concentration of laurel leaf essential oil in the mixed essential oil is 4.17%-5% by volume, and the concentration of cinnamon leaf essential oil is 20%-20.83%. This repellency effect against rove beetles is significantly better than using similar concentrations of laurel leaf essential oil or cinnamon leaf essential oil alone.

[0062] 5. Determination of the optimal fumigation activity concentration of the two essential oils

[0063] (1) Determination of the optimal fumigation activity concentration of cinnamon leaf essential oil

[0064] Add 0.6, 1.2, 1.8, 2.4, and 3.0 μL of cinnamon leaf essential oil to filter paper, respectively. Insert the oil into the inside of the caps of different 600 mL mineral water bottles using a syringe, and then tighten the caps to suspend the filter paper in the dry mineral water bottles, thus creating fumigation concentrations of 1, 2, 3, 4, and 5 μL / L air.

[0065] Ten rove beetles (male or female) were placed in each mineral water bottle containing different fumigation concentrations of cinnamon leaf essential oil. White petroleum jelly was applied to the bottle opening to prevent the beetles from directly contacting the essential oil. These bottles were numbered RGX1 to RGX5, corresponding to fumigation concentrations of 1, 2, 3, 4, and 5 μL / L air, respectively. The grasping rate of the rove beetles was tested after 1, 2, 4, 6, and 8 hours of fumigation. A lower grasping rate indicates a better fumigation effect of the essential oil at that concentration or ratio on the rove beetles. Specifically, the mineral water bottle was gently shaken to allow the rove beetles to return to the bottom. After standing for 3 seconds, the bottle was inverted, and the number of rove beetles falling to the cap during inversion was recorded. Each fumigation concentration was repeated three times (i.e., three bottles were used as replicates for each fumigation concentration). The grasping rate was calculated according to Formula 2, and the fumigation activity was classified according to the standards shown in Table 5.

[0066] Formula 2: Grasp rate (%) = (TF) / T × 100; where T represents the total number of rove beetles in the plastic bottle (i.e., 10 beetles), and F represents the number of rove beetles that fell onto the bottle cap.

[0067] Table 5 Reference Table for Fumigation Activity Classification

[0068]

[0069] The results are shown in Table 6. Figure 5 As shown, in the grasping test of the fumigated Paederus brevis, it was found that the fumigation effect of different concentrations of cinnamon leaf essential oil on Paederus brevis was different. In the RGX1~RGX5 groups, the grasping rate generally showed a downward trend with the change of fumigation time. RGX1 maintained a 90% grasping rate after 1 hour of fumigation on *Rove beetle*, but this rate continued to decline during the 2-8 hour fumigation period, reaching 63.33% after 8 hours, indicating low fumigation effectiveness and a fumigation activity level of II. RGX2's grasping rate decreased to 83.33% after 1 hour of fumigation, continuing to decline during the 2-8 hour period, and significantly decreased to 60.00% after 8 hours, indicating low fumigation effectiveness and a fumigation activity level of II. RGX3's grasping rate decreased to 80.00% after 1 hour of fumigation, continuing to decline during the 2-8 hour period, and significantly decreased to 53.33% after 8 hours, indicating moderate fumigation effectiveness and a fumigation activity level of III. RGX4 maintained a 90% grasping rate after 1 hour of fumigation, continuing to decline during the 2-8 hour period, and significantly decreased to 53.33% after 8 hours, indicating moderate fumigation effectiveness and a fumigation activity level of III. After 1 hour of fumigation, the gripping rate of RGX5 decreased significantly to 43.33%, indicating good fumigation effect and fumigation activity level IV. After 1 hour of fumigation, the gripping rate of RGX5 decreased to 76.67%, and continued to decrease during the period of 2 to 8 hours of fumigation. After 8 hours, the gripping rate decreased significantly to 33.33%, indicating good fumigation effect and fumigation activity level V.

[0070] The results showed that cinnamon leaf essential oil, at fumigation concentrations of 1–5 μL / L air, could not kill *Paederus tectorius*, but it could affect the movement of the beetle. Among the test groups, the RGX5 group showed better fumigation activity against *Paederus tectorius* than the other groups. Figure 5 ).

[0071] Table 6. Results of Determination of Optimal Fumigation Activity Concentration of Cinnamon Leaf Essential Oil

[0072]

[0073] Note: The data in the table were analyzed using GraphPad 10.4 software for one-way ANOVA (P<0.05). Different letters indicate significant differences between different time points within the same experimental group.

[0074] (2) Determination of the optimal fumigation activity concentration of camphor leaf essential oil

[0075] Add 0.6, 1.2, 1.8, 2.4, and 3.0 μL of laurel leaf essential oil to filter paper, respectively. Insert the oil into the inside of the caps of different 600 mL mineral water bottles using a syringe, and then tighten the caps so that the filter paper is suspended in the dry mineral water bottles, thus creating fumigation concentrations of 1, 2, 3, 4, and 5 μL / L air, respectively.

[0076] Ten rove beetles (male or female) were placed in mineral water bottles containing different concentrations of laurel leaf essential oil for fumigation. The beetles were numbered MPX1 to MPX5, corresponding to fumigation concentrations of laurel leaf essential oil of 1, 2, 3, 4, and 5 μL / L air, respectively. The grasping rate of the rove beetles was tested after fumigation for 1, 2, 4, 6, and 8 hours. Specifically, the mineral water bottle was gently shaken to allow the rove beetles to return to the bottom. After standing for 3 seconds, the bottle was inverted, and the number of rove beetles falling to the cap during the inversion was recorded. Each fumigation concentration was repeated three times. The grasping rate was calculated according to Formula 2, and the fumigation activity was classified according to the standards shown in Table 5.

[0077] The results are shown in Table 7. Figure 6As shown, after repeating the grasp test three times on the fumigated Rove beetle, it was found that different concentrations of cinnamon leaf essential oil had different effects on the fumigation of Rove beetle, and the effect was better than that of cinnamon leaf essential oil at the same fumigation concentration; in each of the MPX1~MPX5 groups, the grasp rate showed an overall downward trend with the change of fumigation time. MPX1 showed a low gripping rate of 76.67% after 1 hour of fumigation, continuing to decrease from 2 to 8 hours, and significantly decreasing to 26.67% after 8 hours, indicating good fumigation effect and a fumigation activity level of V. MPX2 showed a low gripping rate of 63.33% after 1 hour of fumigation, continuing to decrease from 2 to 8 hours, and significantly decreasing to 23.33% after 8 hours, indicating good fumigation effect and a fumigation activity level of V. MPX3 showed a low gripping rate of 73.33% after 1 hour of fumigation, decreasing sharply from 2 to 8 hours, and significantly decreasing to 0% after 8 hours, with some rove beetles dying, indicating excellent fumigation effect and a fumigation activity level of V. MPX4 showed a low gripping rate of 53.33% after 1 hour of fumigation, decreasing sharply from 2 to 6 hours, and significantly decreasing to 0% after 6 hours, with some rove beetles dying, and significantly decreasing to 0% after 8 hours, with some rove beetles dying, indicating excellent fumigation effect and a fumigation activity level of V. After h, all rove beetles died, indicating excellent fumigation effect and fumigation activity level V; MPX5's gripping rate decreased to 43.33% after 1 h of fumigation, and significantly decreased to 0 after 4 h, and all rove beetles died after 6 h.

[0078] Table 7. Results of Determination of Optimal Fumigation Activity Concentration of Camphor Tree Leaf Essential Oil

[0079]

[0080] Note: The data in the table were analyzed using GraphPad 10.4 software for one-way ANOVA (P<0.05). Different letters indicate significant differences between different time points within the same experimental group.

[0081] (3) Determination of the optimal fumigation activity ratio of blended essential oils

[0082] Cinnamon leaf essential oil and laurel leaf essential oil were mixed in volume ratios of 1:1, 1:2, 1:3, 1:4, and 1:5 to obtain mixed essential oils with different mixing ratios. 1.2, 1.8, 2.4, 3.0, and 3.6 μL of each mixed essential oil were then dropped onto filter paper. The mixture was then inserted into the inside of the caps of different 600 mL mineral water bottles using a syringe. The caps were then tightened, suspending the filter paper in the dry mineral water bottles, thus creating fumigation concentrations of laurel leaf essential oil to cinnamon leaf essential oil ratios of 1:1, 1:2, 1:3, 1:4, and 1:5 μL / L air.

[0083] Ten rove beetles (male or female) were placed in mineral water bottles containing mixed essential oils at different fumigation concentrations. White petroleum jelly was applied to the bottle openings to prevent the beetles from directly contacting the essential oils. The beetles were numbered MRX1 to MRX5. The fumigation concentrations were cinnamon leaf oil: laurel leaf oil = 1:1, 1:2, 1:3, 1:4, and 1:5 μL / L air, respectively. The grasping rate of the rove beetles was tested after 1, 2, 4, 6, and 8 hours. Specifically, the mineral water bottles were gently shaken to allow the rove beetles to return to the bottom. After standing for 3 seconds, the bottles were inverted, and the number of rove beetles falling to the cap during the inversion was recorded. Each group was repeated three times. The grasping rate was calculated according to Formula 2, and the fumigation activity was classified according to the standards shown in Table 5.

[0084] The experimental results are shown in Table 8 and Figure 7 As shown, after three repeated grasping tests on the fumigated Rove beetle, it was found that the fumigation effect of mixed essential oils with different concentration ratios on the Rove beetle was different. Overall, the grasping rate of the Rove beetle decreased to varying degrees as the fumigation time progressed. MRX1 showed a grasping rate of 73.33% after 1 hour of fumigation, which continued to decrease during the 2-8 hour fumigation period, and significantly decreased to 30.00% after 8 hours, indicating good fumigation effect and a fumigation activity level of V. MRX2 showed a grasping rate of 76.67% after 1 hour of fumigation, which continued to decrease during the 2-8 hour fumigation period, and significantly decreased to 0% after 8 hours, with no deaths of rove beetles, indicating excellent fumigation effect and a fumigation activity level of V. MRX3 showed a grasping rate of 76.67% after 1 hour of fumigation, which continued to decrease during the 2-8 hour fumigation period, and significantly decreased to 0% after 8 hours, with no deaths of rove beetles, indicating excellent fumigation effect and a fumigation activity level of V. MRX4 showed a grasping rate of 63.33% after 1 hour of fumigation, which continued to decrease with the passage of time, decreasing to 6.67% after 6 hours and 8 hours after 8 hours. The concentration of essential oil decreased significantly to 0 after 1 hour, and continued to decrease during the 2-8 hour fumigation period, indicating excellent fumigation effect and a fumigation activity level of V. MRX5 showed a decrease in grasping rate to 60.00% after 1 hour of fumigation, and to 0% after 6 hours (indicating that all rove beetles had lost basic grasping ability). After 8 hours, all rove beetles died. Based on the results of this experiment, an essential oil ratio of 1:4-5 (i.e., MRX4 and MRX5) is the optimal concentration for fumigation activity.

[0085] Table 8 Results of Determination of Optimal Fumigation Activity Ratio of Blended Essential Oils

[0086]

[0087] Note: The data in the table were analyzed using GraphPad 10.4 software for one-way ANOVA (P<0.05). Different letters indicate significant differences between different time points within the same experimental group.

[0088] 6. Determination of the optimal contact activity concentration of the two essential oils

[0089] (1) Determination of the optimal contact toxicity concentration of cinnamon leaf essential oil

[0090] Using the droplet method, cinnamon leaf essential oil was diluted with anhydrous ethanol at different concentrations to form experimental groups, namely 5%, 10%, 15%, 20%, and 25% by volume, numbered RGC1 to RGC5. 0.5 μL of either cinnamon leaf essential oil or anhydrous ethanol (control group, CK) was applied droplet to the pronotum of *Rove beetles*. According to the indoor efficacy test methods and standards for pesticide registration for sanitary insecticides of the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China and the Standardization Administration of China, the experiment was considered effective only when the mortality or knockdown rate observed in the control group was less than 20%. Ten *Rove beetles* (regardless of sex) were treated in each group, and all treatments were repeated three times. The treated *Rove beetles* were transferred to petri dishes coated with white petroleum jelly and reared under conditions of 25±0.5℃, 65±5% humidity, and a light-dark ratio of 12 h:12 h. Mortality rates were calculated at 30, 60, 90, 120, and 150 minutes. The mortality criterion was: if the legs or antennae of the rove beetle were touched with a brush and there was no reaction, the beetle was considered dead. The dead beetles were placed in petri dishes with moistened filter paper and kept under the same rearing conditions. Recovery was observed after 24 hours. The mortality rate at this time represented the mortality rate at the corresponding treatment time. The corrected mortality rate was calculated according to Formula 3, and contact killing activity was classified according to the standards shown in Table 9.

[0091] Formula 3: Corrected mortality rate (%) = (mortality rate of treatment group - mortality rate of control group) / (1 - mortality rate of control group) × 100.

[0092] Table 9 Reference Table for Classification of Contact Killing Activity

[0093]

[0094] The results are shown in Table 10. Figure 8As shown, cinnamon leaf essential oil has certain contact toxicity against rove beetle, and the contact toxicity increases to varying degrees with changes in concentration and contact time. RGC1 showed a corrected mortality rate of 0 at all time points, indicating no contact toxicity against *Rove beetle*. RGC2, after 30 minutes of cinnamon leaf oil infusion, showed a corrected mortality rate of 10.00%, which remained stable at 22.22%–30.00% from 60 to 120 minutes. The corrected mortality rate significantly increased to 33% after 150 minutes, indicating low contact toxicity and a contact toxicity level of II. RGC3 showed a corrected mortality rate of up to 40% after 30 minutes of cinnamon leaf oil infusion. The corrected mortality rate remained around 40% from 30 to 90 minutes, gradually increasing over time, reaching a significant increase to 88.89% after 150 minutes, indicating good contact toxicity and a contact toxicity level of IV. RGC4 showed a corrected mortality rate of 90% after 30 minutes of cinnamon leaf oil infusion, which remained stable until 120 minutes, and then increased significantly after 150 minutes. After 30 minutes, the mortality rate of RGC5 significantly increased to a maximum of 100%, demonstrating excellent contact toxicity and a contact toxicity level of V. The corrected mortality rate of RGC5 reached 80% after 30 minutes of cinnamon leaf essential oil infusion, and significantly increased to a maximum of 100% after 90 minutes, indicating excellent contact toxicity and a contact toxicity level of V. The control group (CK) showed a 10% mortality rate after 90 minutes, which remained unchanged until 150 minutes. Based on the results of this experiment, 25% (v / v) cinnamon leaf essential oil (i.e., RGC5) will be selected for subsequent experiments.

[0095] Table 10 Results of Determination of Optimal Contact Activity Concentration of Cinnamon Leaf Essential Oil

[0096]

[0097] Note: The data in the table were analyzed using GraphPad 10.4 software for one-way ANOVA (P<0.05). Different letters indicate significant differences between different time points within the same experimental group.

[0098] (2) Determination of the optimal contact toxicity concentration of camphor leaf essential oil

[0099] Different concentrations of borneol leaf essential oil were diluted with anhydrous ethanol to form experimental groups, with volume fractions of 5%, 10%, 15%, 20%, and 25%, numbered MPC1 to MPC5. 0.5 μL of the diluted borneol leaf essential oil or anhydrous ethanol (control group, CK) was applied dropwise to the pronotum of *Rove beetles*. Ten *Rove beetles* (sex and no sex) were treated in each group, and all treatments were repeated three times. The treated *Rove beetles* were transferred to petri dishes coated with Vaseline and reared under conditions of 25±0.5℃, 65±5% humidity, and a light-dark ratio of 12 h:12 h. Mortality was recorded after 30, 60, 90, 120, and 150 min. Dead *Rove beetles* were placed in petri dishes with moistened filter paper and kept under the same rearing conditions. Recovery was observed after 24 h; the mortality rate at this time represented the mortality rate at the corresponding treatment time. The corrected mortality rate was calculated according to Formula 3, and contact killing activity was classified according to the standards shown in Table 9.

[0100] The experimental results are shown in Table 11. Figure 9As shown, cinnamon leaf essential oil is superior to laurel leaf essential oil in terms of contact killing effect on rove beetle. With the increase of dilution concentration of laurel leaf essential oil and the change of contact killing time, MPC1~MPC5 all showed varying degrees of increase. MPC1 showed mortality of *Rove beetles* only 150 minutes after instillation of *Cinnamomum camphora* leaf essential oil, with a corrected mortality rate of only 7.41%, indicating extremely low contact toxicity and a Class I contact toxicity activity. MPC2 showed mortality of *Rove beetles* only 60 minutes after instillation of *Cinnamomum camphora* leaf essential oil, with a corrected mortality rate of 10.00%. Following the occurrence of mortality in the control group, the corrected mortality rate decreased after 90 minutes, then increased, reaching only 18.52% after 150 minutes, again indicating extremely low contact toxicity and a Class I contact toxicity activity. MPC3 showed a corrected mortality rate of 13.33% after 30 minutes of instillation of *Cinnamomum camphora* leaf essential oil, reaching 25.93% after 150 minutes. The overall change in corrected mortality rate was not significant, indicating low contact toxicity and a Class II contact toxicity activity. MPC4 showed a corrected mortality rate of 20.00% after 30 minutes of instillation of *Cinnamomum camphora* leaf essential oil, with mortality occurring between 30 and 120 minutes. The corrected mortality rate of MPC5 remained at 20%–26.67% after 30 min, with no significant change, reaching 37.04% after 150 min, indicating low contact toxicity and a contact toxicity level of II. The corrected mortality rate of MPC5 after 30 min of application of borneol leaf essential oil remained at 16.67%, with no significant change between 30 and 90 min, ranging from 16.67% to 20.00%. After 150 min, it significantly increased to the maximum value of 51.85% observed in this experiment, indicating low contact toxicity and a contact toxicity level of II. The control group (CK) showed a mortality rate of 10.00% after 90 min, and the corrected mortality rate remained unchanged until 150 min. Based on the results of this experiment, 25% (v / v) borneol leaf essential oil (i.e., MPC5) will be selected for subsequent experiments.

[0101] Table 11 Results of the test for the optimal contact toxicity concentration of camphor leaf essential oil

[0102]

[0103] Note: The data in the table were analyzed using GraphPad 10.4 software for one-way ANOVA (P<0.05). Different letters indicate significant differences between different time points within the same experimental group.

[0104] (3) Determination of the optimal contact toxicity ratio of blended essential oils

[0105] Based on the results of (1) the determination of the optimal contact toxicity concentration of cinnamon leaf essential oil and (2) the determination of the optimal contact toxicity concentration of laurel leaf essential oil, cinnamon leaf essential oil and laurel leaf essential oil with a volume fraction of 25% were selected and mixed in different volume ratios of laurel leaf essential oil: cinnamon leaf essential oil = 1:1, 1:2, 1:3, 1:4, and 1:5, respectively, to obtain mixed essential oils with different mixing ratios, numbered RGC1 to RGC5. 0.5 μL of the mixed essential oils with different mixing ratios or anhydrous ethanol (control group, CK) was dripped onto the pronotum of *Rove beetle*. Ten *Rove beetles* (regardless of sex) were treated in each group, and all treatments were repeated 3 times. The treated *Rove beetles* were transferred to petri dishes coated with Vaseline and reared under the conditions of 25±0.5℃, 65±5% humidity, and a light-dark ratio of 12 h:12 h. Mortality rates were calculated at 30, 60, 90, 120, and 150 minutes. The dead rove beetles were placed in petri dishes with moistened filter paper and kept under the same rearing conditions. Recovery was observed after 24 hours. The mortality rate at this time represented the mortality rate at the corresponding treatment time. The corrected mortality rate was calculated according to Formula 3, and contact killing activity was classified according to the standards shown in Table 9.

[0106] The experimental results are shown in Table 12. Figure 10As shown, the mixture of cinnamon leaf essential oil and laurel leaf essential oil did not produce the expected synergistic effect. MRC1 showed a corrected mortality rate of 3.33% after 30 minutes of drip-mixed essential oil treatment, which even dropped to 0% at 90 minutes and remained at only 11.11% after 150 minutes, indicating extremely low contact toxicity and a Class I contact toxicity activity. MRC2 did not show any mortality of *Rove beetles* after 30 minutes of drip-mixed essential oil treatment, but only after 60 minutes, with a corrected mortality rate of 3.33%. Again, the corrected mortality rate was 0% at 90 minutes and reached 25.93% after 150 minutes, indicating low contact toxicity and a Class I contact toxicity activity. MRC3 also showed mortality of *Rove beetles* after 60 minutes of drip-mixed essential oil treatment, with a corrected mortality rate of 3.33%, which gradually increased to 25.93% after 150 minutes, indicating low contact toxicity and a Class I contact toxicity activity. MRC4 showed a corrected mortality rate of 10.00% after 30 minutes of drip-mixed essential oil treatment, and then increased from 60 to 90 minutes... The corrected mortality rate remained stable at 22.22%–26.67% during the initial contact period, reaching 48.15% after 150 minutes, indicating a low contact toxicity and a Class I contact toxicity activity. For MRC5, the corrected mortality rate with the mixed essential oil was 20% after 30 minutes, remaining approximately 20% until 90 minutes. The corrected mortality rate only slightly increased to 40.74% after 120 minutes, reaching the maximum value of 51.85% after 150 minutes, again indicating a low contact toxicity and a Class I contact toxicity activity. The control group (CK) showed a mortality rate of 10.00% after 120 minutes, and the corrected mortality rate remained unchanged until 150 minutes. In summary, the results of this experiment suggest that laurel leaf essential oil and cinnamon leaf essential oil exhibit antagonistic effects in terms of contact toxicity.

[0107] Table 12 Results of the test for determining the optimal contact toxicity ratio of blended essential oils

[0108]

[0109] Note: The data in the table were analyzed using GraphPad 10.4 software for one-way ANOVA (P<0.05). Different letters indicate significant differences between different time points within the same experimental group.

[0110] In summary, both cinnamon leaf essential oil and laurel leaf essential oil exhibit repellent, fumigation, and contact-killing effects against *Rove beetle*. The combination of the two has a synergistic effect in repelling *Rove beetle*, but shows antagonistic effects in fumigation and contact-killing. In the repellency experiment, the mixed essential oil obtained by mixing cinnamon leaf essential oil and laurel leaf essential oil (both at 25% volume) in a certain proportion showed a better repellency effect against *Rove beetle* than the single-component essential oil treatment, indicating a good synergistic effect between the two essential oils. When laurel leaf essential oil and cinnamon leaf essential oil (both at 25% volume) were mixed at a volume ratio of 1:4-5, the repellency rate against *Rove beetle* remained at 100% after 8 hours, demonstrating excellent repellency. The repellency rates of the other groups of essential oils also remained above 80% within 6 hours. In fumigation experiments, adding a certain proportion (1~5 μL / L air) of laurel leaf essential oil to cinnamon leaf essential oil at the same concentration (1 μL / L air) resulted in better fumigation than fumigation with only cinnamon leaf essential oil, but not as effective as fumigation with laurel leaf essential oil alone. In contact toxicity experiments, the contact toxicity effect of using a mixture of cinnamon leaf and laurel leaf essential oils was worse than using either cinnamon leaf or laurel leaf essential oil alone.

[0111] In conclusion, cinnamon leaf essential oil and laurel leaf essential oil have the potential to be developed into repellents against rove beetles, providing a theoretical basis for the research and development of natural mixed plant essential oil repellents for rove beetles.

Claims

1. A mixed plant essential oil for repelling rove beetles, characterized in that, It contains cinnamon leaf essential oil and laurel leaf essential oil as active ingredients, with a volume ratio of cinnamon leaf essential oil to laurel leaf essential oil of 4~5:

1.

2. The blended plant essential oil according to claim 1, characterized in that, The cinnamon leaf essential oil in the blended plant essential oil contains 20% to 20.83% by volume, and the laurel leaf essential oil in the blended plant essential oil contains 4.17% to 5% by volume.

3. The blended plant essential oil according to claim 2, characterized in that, The cinnamon leaf essential oil in the blended plant essential oil contains 20% by volume, and the laurel leaf essential oil in the blended plant essential oil contains 5% by volume.

4. A product for repelling rove beetles prepared using the mixed plant essential oils according to any one of claims 1 to 3.

5. The use of the mixed plant essential oil according to any one of claims 1 to 3 in repelling rove beetles.

6. The use of the mixed plant essential oil according to any one of claims 1 to 3 in the preparation of products that repel rove beetles.

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