• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.419-427
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• 2013

The insecticidal activity of 124 plant essential oils and control efficacy of six experimental spray formulations (SF) containing 0.25, 0.5, 1, 2.5, 5, and 10% of the selected oils was examined against both nymph and adult of the citrus flatid planthopper, Metcalfa pruinosa using direct contact applications (leaf dipping and spray). Reponses varied according to dose (1,000 and 500 mg/L). When exposed at 1,000 mg/L for 24 h using leaf dipping assay, 19 essential oils showed strong mortality (100%) among 124 essential oils screened. At 500 mg/L, 100% mortality was observed in cinnamon technical, cinnamon green leaf, cinnamon #500, cassia tree, citronella java and pennyroyal followed by origanum, thyme white, grapefruit, savory, fennel sweet, aniseed and cinnamon bark showed considerable mortality (93.3-80%) against nymphs of M. pruinosa. The moderate mortality (73.3-60%) was found in thyme red, tagetes, calamus, lemoneucalptus and geranium. Oils applied as SF-10% sprays provided 100 % mortality against adult M. pruinosa. One hundred mortalities were achieved in cinnamon technical at >SF-0.5 formulation, in cinnamon #500, cinnamon green leaf and penny royal at >SF-2.5. To reduce the level of highly toxic synthetic insecticides in the agricultural environment, the active essential oils as potential larvicides could be provided as an alternative to control M. pruinosa populations.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.199-205
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• 2010

This study was conducted to investigate the phytotoxic effects of 19 essential oils on seed germination and initial growth of rapeseed (Brassica napus L.). We found that anise, cinnamon, citronella, clove, geranium, lemongrass, mustard and pine oils completely inhibited germination of rapeseed at $100{\times}$ dilute solution. Based on the inhibition rates of rapeseed emergence and initial growth, three essential oils (cinnamon, clove, and geranium) were selected as potential bio-herbicides. Under pre-emergence applications of cinnamon, clove, and geranium oils at 90 kg ai $ha^{-1}$, rates of rapeseed emergence were 7.1, 25.0, and 3.6% and its initial growth were 22.0, 9.9 and 11.0%, respectively.

• International Journal of Clinical Preventive Dentistry
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• v.14 no.4
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• pp.216-221
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• 2018

Objective: In this study, we tried to investigate the antimicrobial activity of natural herbaceous plant-derived essential oils against oral disease-causing bacterial strains and establish the scientific evidences to apply them to the dentifrice, mouthwash, and other uses. Methods: We used the disk diffusion method with 23 types of 100% natural essential oils to verify the antimicrobial effect against Streptococcus mutans, Porphyromonas gingivalis, and Lactobacillus rhamnosus. After adhering to the surface of the plate culture medium, $20{\mu}l$ of the essential oil was prepared, and the diameter of the transparent ring was measured after incubation for 24 hours. All the experiments were repeated three times. Results: Among 23 types of oils, 13 were effective against all three strains: myrrh, ginger, basil, carrot seed, tea tree, patchouli, ylang ylang, cypress, lemongrass, cinnamon, peppermint, lavender, and eucalryptus. Seventeen oils were effective against S. mutans, and myrrh, basil, and carrot seed showed high antimicrobial activity. Eighteen oils were effective against P. gingivalis, and tea tree, carrot seed, and cinnamons showed high antimicrobial activity. Sixteen oils were effective against L. rhamnosus, and carrot seed and peppermint cinnamon showed high antimicrobial activity. Conclusion: Consequently, 13 essential oils showed the antimicrobial activity against three bacterial strains, which indicates these essential oils might be used as the effective materials to suppress the growth of oral-disease inducing microorganisms. Moreover, essential oils that have been analyzed activities in this study will be mixed up within the constant range and analyzed their antimicrobial effects to examine the synergistic activity among them.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.9
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• pp.1281-1287
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• 2015

This study was performed to determine the effect of field pea silages which were the organic acid (OA) alternative of oregano and cinnamon essential oils on fermentation quality and aerobic stability. Whole crop pea was harvested at full pod stage and wilted in the laboratory at the 48 h. The chopped pea was mixed and divided into equal portions allocated to five groups: CON (non-treated), distilled water, denoted as control group; OA group, a mixture of 60% formic acid, 20% sodium formate and 20% water applied at a rate of 5 g/kg fresh forage (Silofarm Liquid, Farmavet); origanum (ORE) group, Origanum onites essential oil at 400 mg/kg fresh forage; cinnamon (CIN) group, cinnamon essential oil at 400 mg/kg fresh forage; origanum+cinnamon (ORECIN) group, a mixture of ORE and CIN applied at an equal rate of 400 mg/kg fresh forage. Cinnamon decreased acetic acid (AA), ammonia nitrogen ($NH_3-N$) and weight loss (WL) at the end of 60 days silage. Crude protein (CP) and dry matter (DM) increased by cinnamon essential oil. Yeasts were not detected in any treatments, including the control, after 7 days of air exposure. The $CO_2$ amount decreased and the formation mold was inhibited in the aerobic period by the addition of cinnamon oil. Oregano did not show a similar effect, but when it was used with cinnamon, it showed synergic effect on AA and during aerobic period, it showed antagonistic effect on mold formation and DM losses. It was found in this study that cinnamon can be an alternative to organic acids.

• The Plant Pathology Journal
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• v.33 no.6
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• pp.582-588
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• 2017

The objective of this study was to determine inhibitory activities of four volatile plant essential oils (cinnamon oil, fennel oil, origanum oil and thyme oil) on in vitro growth of Fusarium oxysporum f. sp. fragariae causing Fusarium wilt of strawberry plants. Results showed that these essential oils inhibited in vitro conidial germination and mycelial growth of F. oxysporum f. sp. fragariae in a dose-dependent manner. Cinnamon oil was found to be most effective one in suppressing conidial germination while fennel oil, origanum oil and thyme oil showed moderate inhibition of conidial germination at similar levels. Cinnamon oil, origanum oil and thyme oil showed moderate antifungal activities against mycelial growth at similar levels while fennel oil had relatively lower antifungal activity against mycelial growth. Antifungal effects of these four plant essential oils in different combinations on in vitro fungal growth were also evaluated. These essential oils demonstrated synergistic antifungal activities against conidial germination and mycelial growth of F. oxysporum f. sp. fragariae in vitro. Simultaneous application of origanum oil and thyme oil enhanced their antimicrobial activities against conidial germination and fungal mycelial growth. These results underpin that volatile plant essential oils could be used in eco-friendly integrated disease management of Fusarium wilt in strawberry fields.

• Research in Plant Disease
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• v.24 no.4
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• pp.292-301
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• 2018

Alternaria leaf spot disease has been a concern during a tomato production in greenhouse. In vitro antifungal activities of vapours of four plant essential oils, cinnamon oil, fennel oil, origanum oil and thyme oil, were investigated during in vitro conidial germination and mycelial growth of Alternaria alternata causing the tomato leaf spots to find eco-friendly alternatives for chemical fungicides. The four plant essential oils showed different antifungal activities against in vitro conidial germination of A. alternata in dose-dependent manners, and cinnamon oil vapour was most effective to suppress the conidial germination. The four plant essential oils showed similar antifungal activities against the in vitro mycelial growth of A. alternata in dose-dependent manners, but low doses of thyme oil vapour slightly increased in vitro mycelial growth of A. alternata. Necrotic lesions on the A. alternata-inoculated tomato leaves were reduced differently depending on kinds and concentrations of plant essential oils. Delayed conidial germination and germ-tube elongation of A. alternata were found on the tomato leaves treated with cinnamon oil and origanum oil vapours at 6 hpi. These results suggest that volatiles from cinnamon oil and origanum oil can be provided as alternatives to manage Alternaria leaf spot during the tomato production eco-friendly.

• International Journal of Industrial Entomology and Biomaterials
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• v.32 no.1
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• pp.26-34
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• 2016

The present study was developed in order to evaluate the effect of five essential oils on the workers of the leaf-cutting ants; Atta sexdens rubropilosa and Acromyrmex subterraneus molestans by contact with a treated surface and ingestion with a treated leaves.. The essential oils of cinnamon, clove and mustard had generally more effective with 5, 10 and 15% concentrations after 24, 48, 72 and 96 h against workers of A. sexdens rubropilosa and A. subterraneus molestans in contact bioassay, but mustard was the most effective in ingestion bioassay on both species. On the other hand, there was no significant difference among the essential oils with 1% concentration and control after 24, 48 and 72 h of treatment in contact and ingestion bioassays against workers of A. sexdens rubropilosa . However, Andiroba oil had less efficiency values in all concentrations been used. Therefore, the essential oils of mustard, cinnamon and clove have contact and ingestion effects on workers of A. sexdens rubropilosa and A. subterraneus molestans, and may be promising on the leaf-cutting ant control.

• Journal of Food Hygiene and Safety
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• v.36 no.5
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• pp.430-439
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• 2021

Essential oils with excellent antibacterial activity were used to study the inhibitory effect against the six types of food poisoning biofilms formed on the surfaces of polyethylene (PE) and stainless steel (SS) that are widely used for food processing instruments and containers. The antibacterial activity of 20 kinds of essential oils was tested using the disk diffusion method. The result showed the degree of antibacterial activity in the following order: cinnamon> clove> lemongrass> peppermint> pine needle (highest to lowest). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of cinnamon and clove oil were in the range of 0.63-1.25 mg/mL and 1.25-2.50 mg/mL, respectively. The MIC and MBC of lemongrass oil were 1.25-2.50 mg/mL and 2.50-5.00 mg/mL, respectively, showing slightly less antibacterial activity. Although the preventive effect of three types of essential oils on the biofilm formation differed slightly depending on food poisoning bacteria, PE, and SS, it was found that the precoating of 0.5% cinnamon, clove, and lemongrass oil on the PE and SS affects the formation of biofilm. Increased essential oil concentration significantly inhibited the biofilm formation for all food poisoning bacteria (P<0.05), and biofilms of Listeria monocytogenes and Staphylococcus aureus were not formed when treated with 0.5% cinnamon and clove oil. The elimination effect of food poisoning bacteria biofilms formed on the surfaces of PE and SS differed depending on the type of food poisoning bacteria. Still, the biofilm elimination effect increased as the essential oil concentration increased, and the biofilm elimination rate of clove oil was generally high. Therefore, this study found that the cinnamon and clove essential oils (0.5%) are suitable natural materials that effectively prevent, inhibit, and remove the biofilms formed by the food poisoning bacteria on the surfaces of polyethylene and stainless steel.

• The Plant Pathology Journal
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• v.31 no.3
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• pp.269-277
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• 2015

Anthracnose caused by Colletotrichum gloeosporioides has been destructive during pepper fruit production in outdoor fields in Korea. In vitro antifungal activities of 15 different plant essential oils or its components were evaluated during conidial germination and mycelial growth of C. gloeosporioides. In vitro conidial germination was most drastically inhibited by vapour treatments with carvacrol, cinnamon oil, trans-cinnamaldehyde, citral, p-cymene and linalool. Inhibition of the mycelial growth by indirect vapour treatment with essential oils was also demonstrated compared with untreated control. Carvacrol, cinnamon oil, trans-cinnamaldehyde, citral and eugenol were among the most inhibitory plant essential oils by the indirect antifungal efficacies. Plant protection efficacies of the plant essential oils were demonstrated by reduced lesion diameter on the C. gloeosporioides-inoculated immature green pepper fruits compared to the inoculated control fruits without any plant essential oil treatment. In planta test showed that all plant essential oils tested in this study demonstrated plant protection efficacies against pepper fruit anthracnose with similar levels. Thus, application of different plant essential oils can be used for ecofriendly disease management of anthracnose during pepper fruit production.

• Korean Journal of Organic Agriculture
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• v.26 no.2
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• pp.259-268
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• 2018

The study investigated the efficacy of four different essential oils on the repellent responses of large black chafer (Holotrichia parallela) Motschulsky (Coleoptera: Scarabaeidae) in organic pear (Pyrus pyrifolia) orchards. Cinnamon, pine, peppermint, and eucalyptus oils were used, and the behavioral responses and repellent effects against H. parallela were investigated under laboratory and field conditions. Adult beetle responses to different oils were examined using a Y-tube olfactometer in the laboratory and four absorbent blocks with each oil in the field. The repellent responses rates of H. parallela were 100% for cinnamon oil; however, only 67% of adult beetles avoided peppermint and eucalyptus oil in the Y-tube olfactometer bioassay. In the field tests, the least damage to leaves was observed on trees treated with cinnamon oil, whereas the most damage was observed in the control (non-treated) trees and those treated with peppermint oil, followed by eucalyptus and pine oil. Therefore, cinnamon oil can be used as a repellent to avoid damage form large black chafers in organic pear orchards.