Formulation of transparent nanoemulsion biopesticide from citronella oil and its manufacturing process

Abstract

This invention reveals a transparent nanoemulsion biopesticide formulation of citronella oil with a particle size of less than 50 nm that functions as a biopesticide. A nano-biopesticide formulation based on citronella oil consisting of (1) citronella oil 5-8%, (2) emulsifier tween 1-2.4%, (3) turpentine oil 0.5-1%, (4) wetting agent Ethylan@SP25 8-10%, (5) glycerol 1-1.6%, and the remainder is distilled water, the total percentage of the ingredients being 100%, which is characterized by a clear / transparent mixture with a particle size of less than 50 nm. This invention functions as a biopesticide to control the fungus Phytophthora capsici and pests of aphids, thrips, and mites on chili plants.

Description

[0001] Description

[0002] FORMULATION OF TRANSPARENT NANOEMULSION BIOPESTICIDE FROM

[0003] CITRONELLA OIL AND ITS MANUFACTURING PROCESS

[0004] Field of the Invention

[0005] This invention is related to a transparent nanoemulsion biopesticide made from citronella oil. This invention is applied as a biopesticide to control the fungus Phytophthora capsid and pests such as aphids, thrips, and mites on chili plants.

[0006] Background of the Invention

[0007] Citronella is a plant that produces essential oils that can be used as natural pesticides. Citronella essential oil has a broad spectrum of biological activity, including antimicrobial, fungicidal, insecticidal, herbicidal, acaricidal, and nematicidal properties. The active compounds contained in citronella oil are citronellol, sabinene, myrsen, p-phelandresitronellal , borneol, geraniol, methyl heptenone, p-bergamoten, trans-methylisoeugenol , p-cadinene, elemol, and caryophyllene (AgroMedia, 2008) . The most dominant components of citronella are citronellal (32-45%) , geraniol (12-18%) , citronellol (11-15%) , geranyl acetate (3-8%) , citronellyl acetate (2-4%) , citral, cavicol, eugenol, elemol, cadinol, cadinene, vanillin, limonene, and camphene (Sastrohamidjojo, 2004) . The stem and leaves also contain substances such as geraniol, methylheptenone, organic acids, and citronellal (Lubis, 2012) .

[0008] The use of citronella essential oil as a biopesticide has been reported to control pests, such as mealybugs (Paracoccus marginatus L.) on papaya plants (Octriana et al., 2021) , cocoa pod-sucking pests (Helopeltis spp . ) (Supriyatdi et al., 2023) and pepper pod-sucking pests (Dasynus piperis China) (Laba and Rohimatun, 2013) . Several studies have shown the antifungal potential of citronella essential oil, including its ability to suppress the pathogen Colletotri chum sp . on shallots, Fusarium oxysporum on tomatoes, and Colletotrichum gloeosporioides , which causes anthracnose on apples (Kurniasih et al., 2014; Peixoto et al., 2023; Nugraheni et al., 2014) .

[0009] Nanoemulsions have the advantages of fine, uniform granules, improved stability and bioavailability, and more effective penetration. The type of surfactant, dosage, and emulsifying time influence the appearance and microstructure of the emulsion, as well as the size and stability of the citronella oil nanoemulsion. Essential oil release can be effectively controlled by varying the amounts of surfactant and glycerol. Increasing the surfactant concentration results in reduced particle size, improved homogeneity, and extended release and protection times. In addition, the release of citronella oil from high amounts of glycerol is much slower compared to the release of citronella oil from low amounts of glycerol, resulting in a longer mosquito protection time (Sakulku et al., 2009) . Nano Citronella Plus showed significant ovicidal, larvicidal, and repellent effects against the fly Cochliomyia hominivorax (Bricarello et al., 2021) . Citronella nanoemulsion is effective in controlling the warehouse pest Oryzaephilus surinamensis and is a promising alternative to chemical pesticides for protecting stored products (Gharsan et al . , 2022) .

[0010] Citronella oil nanoemulsion contains 5% (w) citronella oil, 6% (w) surfactant (EL-40) , and 89% (w) deionized water. Citronella oil nanoemulsion inhibits the growth of Pantoea ananatls bacteria at a maximum concentration of 50% (EC50) of 74.85 mg -L-l (Chen et al, 2022) . Citronella oil nanoemulsion can suppress VSD disease in cocoa plants by 4.33-21.11% (Noveriza et al, 2018) . Citronella oil nanoemulsion at a concentration of 0.50% is effective in controlling the seed-borne fungus Fusarium fujikuroi (Harahap et al, 2022) . Citronella nanoemulsion 10 (CNE10) was most active against Rhizoctonia solani (ED50 25.64 mg L-l) and Sclerotium rolfsii (ED50 20.88 mg L-) (Ali et al., 2017) .

[0011] A search of Chinese patent number CN117025298A, entitled "Lemongrass essential oil nanoemulsion and preparation method thereof, " shows that a lemongrass oil nanoemulsion composed of 10 g lemongrass oil, 9 g Tween 80, 1 g Span 80, 10 g absolute ethanol, and 100 ml distilled water has an inhibitory effect on Staphylococcus aureus and Escherichia coll. Patent number WO2009132342A1, entitled "Nanoemulsions for treating fungal, yeast, and mold infections, " tests nanoemulsions derived from several plants with particle sizes less than 1000 nm that can function as control agents for fungi, mold, and yeast. Nanoemulsion droplets consist of an aqueous phase, at least one type of oil, at least one surfactant, and at least one organic solvent. Chinese patent number CN110506764A, entitled "A kind of farm disinfecting, deodorizing nanoemulsion and its preparation method and application, " describes a nanoemulsion containing citronella oil that can be used to eliminate odors in livestock farms. The nanoemulsion contains active ingredients and auxiliary ingredients, and the active ingredients include 1-30 parts of salt (polyhexamethyleneguanidine) , 1-25 parts of peptide, 1-25 parts of subtilisin, 1-15 parts of garlic oil, 1-15 parts of borneol, 1-15 parts of thymol, 1-10 parts of eucalyptus, 1-10 parts of menthol, 1-10 parts of citronella essential oil, 1-10 parts of citronella oil, auxiliary ingredients include 5-20 parts of surfactant, 1-20 parts of co-surf actant , 5-20 parts of pharmaceutical water. Patent number CN110915799A is used as an anti-feedant and anti-insect. The nanoemulsion used consists of 1 or more types of essential oils measuring 80-300 nm.

[0012] Indonesian patent number IDS000006067 on botanical insecticide from a mixture of nutmeg (Myristica fragrans) and citronella (Cymbopogon nardus) essential oils for environmentally friendly warehouse pest control. A mixture of M. fragrans and C. nardus essential oils applied to C. chinensis imago with a ratio of 1:1 / (v:v) in observations up to 72 hours after treatment (HAT) has the potential as a botanical insecticide against C. chinensis pests .

[0013] The weakness of the citronella essential oil biopesticide nanoemulsion mentioned in Indonesian Patent no. IDS000002904 entitled "Nano Biopesticide Formula with Citronella Oil Main Ingredients" has a low viscosity so that when applied it evaporates easily, is unstable so that its effectiveness quickly decreases. The particle size of the citronella oil nanoemulsion formulation is still quite large, namely 100-200 nm. Particle size greatly determines its effectiveness against target pests and pathogens, smaller particle sizes are able to spread and absorb more quickly.

[0014] The research has not yet found a transparent nanoemulsion formula of citronella oil with a particle size of less than 50 nm as a biopesticide, as described in this proposed invention. Based on information and reference searches, particle size influences the effectiveness of the active ingredient in this formulation. Another advantage of this invention is that the formulation's effectiveness remained unchanged after 11 months of storage.

[0015] Summary of the Invention

[0016] A transparent nanoemulsion biopesticide formulation of citronella oil with a particle size of less than 50 nanometer (nm) which functions as a biopesticide consists of: (1) citronella oil 5-8%, (2) emulsifier tween 1-2.4%, (3) turpentine oil 0.5-1%, (4) emulsif ier / wetting agent Ethylan@SP25 8-10%, (5) glycerol 1-1.6%, and (6) the remainder is distilled water to reach 100%.

[0017] The transparent nanoemulsion formula of citronella oil of this invention, the particles of the active ingredient of citronella oil used are less than 50 nm in size. The process of making the transparent nanoemulsion formulation of citronella oil is as follows: (a) mixing citronella oil with tween emulsifier, turpentine oil and Ethylan@SP25 emulsifier according to the ratio until homogeneous for 15 minutes at a speed of 500-700 rpm, this mixture is called the organic phase, (b) mixing glycerol with distilled water according to the ratio until homogeneous for 10 minutes at a speed of 500-700 rpm, this mixture is called the water phase, (c) mixing the organic phase according to step a) into the water phase according to step b) slowly and continuously until it becomes homogeneous for 60 minutes at a speed of 500-700 rpm to produce a clear / transparent mixture. The transparent nanoemulsion formula of citronella oil in this invention functions as a biopesticide to control the fungus Phytophthora capsid and pests such as aphids, thrips, and mites on Tanjung 2 variety chili plants.

[0018] Detailed Description

[0019] This invention reveals a transparent nanoemulsion of citronella oil with a particle size of less than 50 nm that functions as a biopesticide.

[0020] The transparent citronella nanoemulsion biopesticide formulation consists of (1) citronella oil 5-8%, (2) emulsifier tween 1-2.4%, (3) turpentine oil 0.5-1%, (4) glycerol 1-1.6%, emulsifier Ethylan@SP25 8-10% and the remainder is distilled water, the total percentage of ingredients being 100%, which is characterized by a clear, transparent (colorless) emulsion with a particle size of less than 50 nm.

[0021] The process of making a transparent citronella nanoemulsion biopesticide formula is as follows: a) mixing citronella oil with tween emulsifier, Ethylan@SP25 emulsifier 8-10% and turpentine oil according to the ratio until homogeneous for 15 minutes at a speed of 500-700 rpm, this mixture is called the organic phase, b) mixing glycerol with distilled water according to the ratio until homogeneous for 10 minutes at a speed of 500-700 rpm, this mixture is called the water phase, c) mixing the organic phase into the water phase slowly and continuously until it becomes homogeneous for 45 minutes at a speed of 500-700 rpm, resulting in a clear, transparent (colorless) mixture.

[0022] The liquid formula was then analyzed using a particle size analyzer (PSA) until it reached the desired size. The PSA analysis results are shown in Table 1, indicating a particle size of 21 nm for the transparent citronella oil nanoemulsion formulation. The active compounds in the formula were also analyzed (Table 2) . Table 1. Results of measurements of citronella emulsion nano particles using the Dynamic light scattering (DLS) method .

[0023] Analysis

[0024] No. Sample Name Method Results Unit

[0025] Type

[0026] 1. NS non Size Dynamic 141.3 d.nm transparent (Zaverage) light

[0027] PDI scattering

[0028] (DLS)

[0029] 2. NS Size Dynamic 21.0 d.nm transparent (Zaverage) light

[0030] PDI scattering „

[0031] 0.436

[0032] (DLS)

[0033] 5 Table 2. Content of the main compound components in non-transparent

[0034] NS and transparent NS formulations using the GCMS method The active compounds detected in the transparent citronella oil nanoemulsion formulation were Alpha-Pinene (5.08%) , (R) — (+)—

[0035] Citronellic acid (4.38%) , 6-Octen-l-ol, 3, 7-dimethyl-, acetate (1.96%) and Geranyl acetate (1.55%) .

[0036] 5 This invention has been tested in the laboratory against the fungus Phytophthora capsid (Table 3) and field tests against aphids, thrips, and mites on chili plants of the Akar variety (Tables 4, 5, and 6) .

[0037] Table 3. Inhibitory of citronella oil nanoemulsion formulation 10 against Phytophthora capsid with a concentration of 0.5%

[0038] - 2.0% after being stored for 11 months

[0039] In Table 3, it can be seen that the transparent nanoemulsion formulation of citronella oil with a concentration of 0.5% was 15 able to inhibit the growth of P. capsid fungus by 90% better than fungicides .

[0040] The results of testing on chili seeds of the Akar variety at a concentration of 0.5-1.5% did not differ significantly in terms of chili seed germination, vigor index and growth rate of chili 20 seeds compared to the control (distilled water) and chemical fungicide (Table 4) .

[0041] Table 4. Effect of transparent nanoemulsion of citronella oil on the germination of chili seeds of the Akar variety.

[0042] The results of testing transparent citronella nanoemulsion after being stored for 11 months on Tanjung 2 variety chili seeds at a concentration of 1.5-2.5% can be seen in Table 5. Table 5. Effect of transparent nanoemulsion of citronella oil after

[0043] 11 months of storage on the germination of Tanjung 2 variety chili seeds.

[0044] The results of testing against aphids, Thrips tabaci and mites (Tetranychus sp . ) on chili plants of the Akar variety, the effectiveness of the transparent NS formula against thrips and mite attacks, was the same as the effectiveness of chemical insecticide applications (Tables 6, 7, and 8) . Table 6. Effectiveness of the transparent citronella nanoemulsion formula and chemical insecticides on the intensity of aphid attacks (%) on chili plants of the Akar variety in the time range of 21-98 days after planting (DAP) .

[0045] Table 7. Effectiveness of transparent citronella nanoemulsion formula and chemical insecticides on the intensity of Thrips pest attacks (%) on chili plants of the Akar variety in the time range of 21-98 days after planting (DAP) .

[0046] 10 Table 8. Effectiveness of transparent citronella nanoemulsion formula and chemical insecticides on the intensity of mite pest attacks on chili plants of the Akar variety in the time range of 21-98 days after planting (DAP) .

[0047] Observations after applying the transparent NS formula to Akar chili plants in the field showed significantly higher chili production (25% increase in production) compared to chemical insecticide applications. Meanwhile, total chili fruit production losses were lower compared to chemical insecticides (Table 9) .

[0048] Table 9. Effect of application of transparent NS formula and chemical insecticides on total chili fruit production

[0049] (kg) and loss of chili production of Akar variety (%) .

[0050] Total chili Treatment Yield loss (%) production (kg)

[0051] NS transparent 600 a 30.79 a

[0052] Chemical insecticides 482.2 b 32 .93 a

[0053] The conclusion of this study is that the transparent NS formula (with the active ingredient of citronella oil that has been reformulated into a transparent nanoemulsion formula with a particle size of less than 50 nm) can be applied as an alternative to reduce the use of chemical insecticides.

Claims

Claims1. A transparent nanoemulsion biopesticide formulation of citronella oil, consisting of: a) citronella oil which has particles less than 50 nanometers, as much as 5-8%; b) tween emulsifier, as much as 1-2.4%; c) turpentine oil, as much as 0.5-1%; d) emulsif ier / wetting agent Ethylan@SP25, as much as 8-10%; e) glycerol 1-1, as much as 6%; and f) distilled water until it reaches 100%.

2. A process for making transparent nanoemulsion of citronella oil which functions as a biopesticide with the following stages : a) mixing citronella oil with tween emulsifier, turpentine oil and ethylene according to the ratio in claim 1 until homogeneous for 15 minutes at a speed of 500-700 rpm, this mixture is called the organic phase; b) mix glycerol with distilled water according to the ratio in claim 1 until homogeneous for 10 minutes at a speed of 500- 700 rpm, this mixture is called the water phase; c) mix the organic phase according to step a) into the water phase according to step b) slowly and continuously until it becomes homogeneous for 60 minutes at a speed of 500-700 rpm to produce a clear, transparent citronella oil nanoemulsion mixture.

3. A transparent nanoemulsion of citronella oil as per claim 1, wherein the active ingredient particles of citronella oil have the characteristic of functioning as a biopesticide to control the fungus Phytophthora capsid by 90% better than fungicides, and have the same effectiveness as chemical insecticides in controlling aphids, thrips, and mites on chili plants.

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