Essential oil composition and method for preventing and treating book lice bostrychus

Abstract

The invention relates to the field of pest prevention and control, and particularly discloses an essential oil composition and method for preventing and controlling book lice bostrychus, active ingredients of the essential oil composition comprise thyme essential oil and lavender essential oil, and the volume ratio of the thyme essential oil to the lavender essential oil is (8-10): 1. The method for preventing and controlling the book lice botrytis comprises the step of treating the breeding environment of the book lice botrytis botrytis by using the oil composition in a fumigation manner. The composition provided by the invention has a remarkable synergistic interaction effect on the bostrychus bostrychus, especially adults of the bostrychus bostrychus, and is environment-friendly, and the dosage can be reduced.

Description

Technical Field

[0001] This invention relates to the field of pest control, and more particularly to an essential oil composition and method for controlling booklice. Background Technology

[0002] Booklice ( Liposcelis bostrychophila Booklicerella curvatureii is a globally distributed storage pest that primarily damages stored grains, cereals, books, archives, and traditional Chinese medicine materials. It is also one of the main pests of organic artifacts in museums (such as ancient books, archives, animal specimens, and folk artifacts made of silk and hair). Due to its small size, short reproductive cycle, and susceptibility to pesticide resistance, booklicerella curvatureii is extremely difficult to control. Traditional control methods mainly rely on chemical fumigants (such as phosphine and methyl bromide) and pyrethroid insecticides. However, the long-term and extensive use of chemical pesticides has led to serious pesticide resistance problems, and also presents numerous drawbacks such as pesticide residues, environmental pollution, and potential health risks to operators. With increasing awareness of food safety and environmental protection, the development of efficient, low-toxicity, and environmentally friendly new control technologies has become an urgent need in this field.

[0003] Pest control in museums and other similar venues is a global challenge, requiring extremely high levels of safety from pesticides (non-corrosive, residue-free). Plant-derived pesticides, due to their natural origin, easy degradation, and relative safety to non-target organisms, are considered an ideal alternative to chemical pesticides. Among them, plant essential oils, due to their volatility, are particularly suitable for fumigation control of pests in enclosed environments (such as warehouses and containers). Existing technologies have yielded numerous studies reporting the fumigation activity of single plant essential oils against a variety of pests. For example, published research indicates that thyme essential oil, peppermint essential oil, and lavender essential oil all exhibit certain biological activities against some stored-store pests.

[0004] However, existing plant-based pest control solutions, especially those involving essential oil applications, generally suffer from the following defects and shortcomings: First, the use of single essential oils often suffers from insufficient activity or requires excessively high effective concentrations. To achieve the desired prevention and treatment effect, a large dose is often required, which increases costs. Furthermore, high concentrations may produce unpleasant odors or have a potential impact on the quality of stored goods, thus limiting their practical application potential.

[0005] Second, although there are existing teachings on the simple mixing of multiple essential oils, most of them remain at the level of empirical and rough compounding, lacking in-depth research on the structure-activity relationship between specific compounding ratios and their biological activities; most compounding is just a simple mixing, and its effects are mostly additive, or even antagonistic, failing to achieve synergistic effects.

[0006] Third, for the difficult-to-control storage pest, booklice, there is a lack of scientifically validated, synergistic, and dosage-specific compound essential oil fumigant in the existing technology; those skilled in the art cannot obtain clear inspiration from the existing technology to screen out the best essential oil combination and its precise ratio that has a significant synergistic effect on adult booklice.

[0007] Therefore, there is an urgent need in this field to develop an essential oil compound composition and method that has a significant synergistic effect on booklice, especially adult booklice, can reduce the dosage, and is environmentally friendly. Summary of the Invention

[0008] In view of this, the object of the present invention is to provide an essential oil compound composition and method that has a significant synergistic effect on booklice, especially adult booklice, reduces the dosage required, and is environmentally friendly.

[0009] To achieve the above objectives, the present invention provides an essential oil composition for preventing and treating booklice, wherein the active ingredients of the essential oil composition consist of thyme essential oil and lavender essential oil, and the volume ratio of thyme essential oil to lavender essential oil is (8-10):1.

[0010] As a further improvement to the above technical solution, the volume ratio of the thyme essential oil to the lavender essential oil is 9:1.

[0011] As a further improvement to the above technical solution, the essential oil composition is used to control adult booklice.

[0012] As a further improvement to the above technical solution, the essential oil composition exerts its effect through fumigation.

[0013] As a further improvement to the above technical solution, the thyme essential oil contains 35.17% thymol and 18.72% linalool by mass; the lavender essential oil contains 37.91% linalyl acetate by mass.

[0014] As a further improvement to the above technical solution, the essential oil composition is prepared by mixing thyme essential oil and lavender essential oil in a set volume ratio.

[0015] On the other hand, the present invention also provides a method for preventing and controlling booklice, including using the above-mentioned essential oil composition to treat the breeding environment of booklice by fumigation; it can be applied to specific spaces such as cultural relic warehouses, storage cabinets, and specimen cabinets, and can achieve precise targeting; for example, slow release of essential oil in cultural relic storage cabinets and packaging boxes can create a microenvironment that pests are unwilling to approach, thereby effectively preventing the occurrence of pests and realizing the transformation from "treatment" to "prevention".

[0016] Compared with the prior art, the essential oil composition and method for preventing and treating booklice provided by the present invention have at least the following beneficial technical effects: 1. Through extensive creative work, this invention has for the first time discovered that when thyme essential oil and lavender essential oil are combined in a specific volume ratio (e.g., (8-10):1, preferably 9:1), they exhibit a significant synergistic effect against adult booklice, rather than a simple additive effect. Data from the embodiments of this invention shows that when thyme essential oil and lavender essential oil are combined in a 9:1 ratio, their co-toxicity coefficient (CTC) reaches 128.36, clearly exceeding the synergistic effect threshold of 120. More importantly, the median lethal concentration of this compound is even lower than that of the most active thyme essential oil alone, further demonstrating the synergistic effect of the two and significantly improving insecticidal efficiency.

[0017] 2. Due to the synergistic effect, the compound composition of the present invention can effectively reduce the dosage of essential oil per unit space while achieving the same or even better control effect. This directly brings the following benefits: on the one hand, it reduces the cost of raw materials, making the plant-based control solution more economical and competitive in the market; on the other hand, due to the reduction in dosage, it minimizes the potential residual risk of essential oil on stored goods and reduces the potential impact on the environment, which is more in line with the concept of green control.

[0018] 3. This invention is not a simple mixture of multiple essential oils, but provides a precise optimal volume ratio range (8-10:1) and an optimal point (9:1) that has been rigorously verified by bioassays. The data from the examples show that the insecticidal effect at this ratio is significantly better than other ratios (such as 7:1 and 10:1), proving the specificity and unpredictability of its effect. It provides a reliable technical solution for developing a highly efficient and stable fumigant for booklice, and completely overcomes the blindness and uncertainty of essential oil compounding in the prior art.

[0019] 4. The composition and method provided by this invention are specifically designed for adult booklice, a difficult-to-control storage pest, with a clear target. Through fumigation, they can effectively penetrate into the hidden corners where the pests live, solving the problem of traditional spraying methods not being able to cover the area, and achieving highly efficient control of hidden pests.

[0020] 5. The active ingredients used in this invention are all natural plant essential oils, which are biodegradable in the environment, safe for humans and animals, have little impact on non-target organisms, and are not likely to cause pests to develop resistance. Compared with chemical fumigants, this invention provides a safer and more sustainable integrated pest management solution, which is particularly suitable for sensitive places with strict restrictions on chemical residues, such as museums, grain storage facilities, Chinese medicinal herb preservation facilities, libraries, and archives. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute a limitation thereof.

[0022] Figure 1 The mortality curves of adult booklice (Thymus odoratus) under different blending ratios of thyme and lavender essential oils are shown. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Example

[0024] 1. Materials and Methods 1.1 Instruments and Reagents HWS-260 constant temperature and humidity chamber (Ningbo Southeast Instrument Co., Ltd.); pipettes (Eppendorf, 10~1000 μL); disposable pipette tips (2.5 μL, 10 μL, 200 μL, 1000 μL); 200 mL Erlenmeyer flasks and 9 cm glass petri dishes (Haimen Ruixingkang Experimental Equipment Store), etc. Lamiaceae essential oils (thyme oil, peppermint oil, and lavender oil, etc.) were all purchased from Chongqing Daily Chemical Industry Research Institute.

[0025] 1.2 Insect source Booklice ( Liposcelis bostrychophila Artificial rearing was completed in the laboratory of the National Cultural Heritage Administration Key Scientific Research Base for the Control of Harmful Organisms in Museum Collections (Chongqing China Three Gorges Museum). Rearing conditions: The insects were kept in a dark incubator at 27±1℃ and 75±5% relative humidity, fed with a mixture of milk powder, yeast, and flour in a 10:1:1 mass ratio. Insecticidal activity experiments were conducted on 1-week-old adults and 3-4-day-old larvae.

[0026] 1.3 Experimental Methods 1.3.1 Fumigation Activity Determination Method The fumigation activity assay method was modified from the Erlenmeyer flask fumigation method. The experimental procedure was as follows: First, 30 adult booklice were placed at the bottom of a flask. Then, 10 μL of essential oil or n-hexane was added dropwise onto a filter paper disc (2.5 cm × 1.5 cm), secured with a rubber band, and suspended in the center of a 260 mL Erlenmeyer flask. Finally, the flask was immediately sealed with a sealing film. n-Hexane was used as a negative control. The essential oils were diluted, with five concentration gradients for each essential oil and three biological replicates for each concentration. The observation interval for booklice larvae was 24 hours. All data were analyzed using SPSS V22.0 software, and the median lethal concentration (LC50) was calculated using Probit analysis. 50), and estimate the 95% confidence interval (CI), relevant parameters and chi-square value.

[0027] 1.3.2 Essential Oil Blending Methods Thyme essential oil was combined with the remaining five essential oils for screening. Initial screening was conducted on booklice *Ixodes curvatus* using air doses of 2 μL / L and 50 μL / L, with volume ratios of 1:1, 1:3, 1:5, 1:7, and 1:9 (the remaining five essential oils were used alone: ​​thyme essential oil). The insect with the highest mortality rate was selected from the initial screening, and fumigation treatments were performed at different concentration gradients to calculate the median lethal concentration (LC50). 50 ), and estimate the 95% confidence interval (CI), relevant parameters and chi-square value.

[0028] 1.3.3 Co-toxicity coefficient (CTC) of essential oil blends According to the "NYT 1156.6-2006 Guidelines for Indoor Bioassay Testing of Pesticides - Part 7: Determination of Combined Effects of Mixtures", SPSS and Excel software were used to analyze and process the experimental data, and the regression curve equation for the toxicity of the essential oil to pests, Y = aX + b, and the median lethal concentration (LC50) were obtained. 50 The 95% confidence limit and correlation coefficient R were used. The co-toxicity coefficient (CTC value) of the mixture was calculated using thyme essential oil as the standard and according to Sun Yunpei's method.

[0029] The co-toxicity coefficient (CTC value) of the mixture is calculated according to formulas (1), (2), and (3): ATI =S / M*100 (1) In the formula: ATI – Actual Measured Toxicity Index of Mixtures; S —LC of thyme essential oil 50 The unit is microliters per liter of air (μL / L air). M LC of the mixture 50 The unit is microliters per liter of air (μL / L air).

[0030] TTI = TI A * P A + TI B * P B (2) In the formula: TTI —Theoretical toxicity index of the mixture; TI A —A. Toxicity index of drug A; P A —The percentage content of drug A in the mixture, expressed as a percentage (%). TI B —Toxicity index of drug B; P B —Percentage content of agent B in the mixture, in percentage (%). CTC = ATI / TTI * 100 (3) In the formula: CTC —Cotoxicity coefficient; ATI —Measured toxicity index of the mixture; TTI —Theoretical toxicity index of mixed preparations.

[0031] Co-toxicity coefficient of compound agents: CTC≥120 is judged as synergistic effect; CTC≤80 is judged as antagonistic effect; 80<CTC<120 is judged as additive effect.

[0032] 2 Results 2.1 Fumigation Activity Six essential oils from Lamiaceae plants, including thyme, exhibited varying fumigation activities against the larvae of the booklice *Cypripedium curvatum*. The results are detailed in Table 1. Among them, thyme essential oil showed the highest fumigation activity against adult booklice (LC50). 50 =0.78 μL / L air), followed by spearmint essential oil (LC). 50 =2.68 μL / L air), with no significant difference in activity among the other four essential oils (clove basil, rosemary, peppermint, and lavender). 50 =4.14, 4.88, 5.00 and 6.17 μL / L air).

[0033] Table 1. Fumigation activity of six Lamiaceae essential oils against booklice.

[0034] 2.2 Screening of fumigation insecticide formulations The fumigation activity experiments of six Lamiaceae essential oils against *S. curvatum* revealed that thyme exhibited the highest fumigation activity against adult *S. curvatum*. Therefore, thyme essential oil was selected for initial screening in combination with the remaining five Lamiaceae essential oils, and the results are detailed in Table 2. The initial screening fumigation activities of thyme essential oil and the remaining five Lamiaceae essential oils against *S. curvatum* were as follows: at a ratio of 9:1 (thyme and lavender essential oils) and an air concentration of 2 μL / L, the mortality rate of adult *S. curvatum* reached 94.44% after fumigation treatment. The second highest mortality rate was 92.70% at a ratio of 7:1. Therefore, a 9:1 ratio of thyme and lavender was confirmed as the optimal ratio for fumigating and controlling adult *S. curvatum*. The experimental results of thyme and lavender essential oils at various ratios are shown in Table 3, and their curves are shown in Table 3. Figure 1 .

[0035] Table 2 Preliminary screening of blends of thyme essential oil and the remaining 5 Lamiaceae essential oils

[0036] Table 3. Experimental results of thyme essential oil and lavender essential oil at various ratios.

[0037] To determine whether the fumigation effect of thyme and lavender on adult booklice was enhanced, a co-toxicity test was conducted, as detailed in Tables 3 and 4. Thyme and lavender at a 9:1 ratio showed a synergistic effect on adult booklice fumigation, with a co-toxicity coefficient of 128.360.

[0038] Table 4. Fumigation activity of thyme and lavender essential oils combined with adult booklice.

[0039] 3. Conclusion Thyme essential oil is the most effective of the three essential oils when used alone against adult booklice. In a compound formula, thyme and lavender in a 9:1 ratio have a synergistic effect on the fumigation of adult booklice.

[0040] like Figure 1 As shown, the mortality rate reached its highest point (94.44%) at a ratio of 9:1, forming a clear peak. The effect at this point was significantly higher than that at adjacent ratios (71.67% at 8:1 and 57.91% at 10:1).

[0041] 4. Main components and content of essential oils in the experiment The GC-MS (gas chromatography-mass spectrometry) area percentage reports for thyme oil and lavender oil are shown in Tables 4 and 5, respectively, and their main compounds are summarized in Table 6.

[0042] Table 4. Report on Percentage of Thyme Oil Area

[0043] Table 5. Report on Percentage of Lavender Oil Area

[0044] Table 6. Main compound composition of thyme oil and lavender.

[0045] Finally, it should be noted that this article uses specific examples to illustrate the principles and implementation methods of the present invention. The above description of the embodiments is only for the purpose of helping to understand the core ideas of the present invention. Without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. An essential oil composition for preventing and treating booklice, characterized in that: The active ingredients of the essential oil composition consist of thyme essential oil and lavender essential oil, wherein the volume ratio of thyme essential oil to lavender essential oil is (8-10):

1.

2. The essential oil composition for preventing and treating booklice according to claim 1, characterized in that: The volume ratio of the thyme essential oil to the lavender essential oil is 9:

1.

3. The essential oil composition for preventing and treating booklice according to claim 1, characterized in that: The essential oil composition is used to control adult booklice.

4. The essential oil composition for preventing and treating booklice according to claim 1, characterized in that: The essential oil composition works through fumigation.

5. The essential oil composition for preventing and treating booklice according to claim 1, characterized in that: The thyme essential oil contains 35.17% thymol and 18.72% linalool by mass; the lavender essential oil contains 37.91% linalyl acetate by mass.

6. The essential oil composition for preventing and treating booklice according to claim 1, characterized in that: The essential oil composition is prepared by mixing thyme essential oil and lavender essential oil in a set volume ratio.

7. A method for preventing and controlling booklice, characterized in that: This includes using the essential oil composition of any one of claims 1 to 6 to treat the breeding environment of booklice by fumigation.

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