Acaricidal Activity Of Essential Oils Research Articles

The effects of clove oil on the enzyme activity of Varroa destructor Anderson and Trueman (Arachnida: Acari: Varroidae).

Varroa destructor, a key biotic threat to the Western honey bee, has played a major role in colony losses over the past few years worldwide. Overuse of traditional acaricides, such as tau-fluvalinate and flumethrin, on V. destructor has only increased its tolerance to them. Therefore, the application of essential oils in place of traditional pesticides is an attractive alternative, as demonstrated by its high efficiency, lack of residue and tolerance resistance. To study the acaricidal activity of essential oils, we used clove oil (Syzygium aromaticum L.), a typical essential oil with a wide range of field applications, and examined its effects on the enzyme activities of Ca2+-Mg2+-ATPase, glutathione-S-transferase (GST) and superoxide dismutase (SOD) and its effects on the water-soluble protein content of V. destructor body extracts after exposure to 0.1 μl and 1.0 μl of clove oil for 30 min. Our results showed that the water-soluble protein content significantly decreased after the treatments, indicating that the metabolism of the mites was adversely affected. The bioactivity of GSTs increased significantly after a low dosage (0.1 μl) exposure but decreased at a higher dosage (1.0 μl), while the activities of SOD and Ca2+-Mg2+-ATPase were significantly elevated after treatments. These results suggest that the protective enzyme SOD and detoxifying enzymes Ca2+-Mg2+-ATPase and GST contributed to the stress reaction of V. destructor to the essential oils and that the detoxification ability of V. destructor via GST was inhibited at higher dosages. Our findings are conducive to understanding the physiological reactions of V. destructor to treatment with essential oils and the underlying mechanisms behind the acaricidal activities of these natural products.

Acaricidal activity of essential oils of Bursera graveolens (Kunth) Triana & Planch and Schinus molle L. on unengorged larvae of cattle tick Rhipicephalus (Boophilus) microplus (Acari:Ixodidae)

The use of bio-derivatives as acaricides would be an effective and safe method of tick control. The acaricidal effect of essential oils obtained from Bursera graveolens (Burseraceae) and Schinus molle (Anacardiaceae), traditionally used by indigenous Ecuadorian medicine as insecticides, was tested on larvae of cattle tick Rhipicephalus (Boophilus) microplus. Essential oils were obtained from mature fruits by hydrodistillation and analyzed by gas chromatography. The acaricidal activity of essential oils against larvae was measured by larval package test with six concentrations of each essential oil. In total, sixteen compounds were identified in B. graveolens and twenty-one in S. molle essential oil. The mortalities of larvae in assays conducted with B. graveolens essential oil ranked from 35.43 to 100%; in S. molle from 5.58 to 100%. The obtained results show a clear and promising acaricidal effect of both essential oils over larvae of R. (B.) microplus.

Chemical Composition and Acaricidal Activities of Essential Oils of Litsea cubeba Fruits and Mentha arvensis Leaves Against House Dust and Stored Food Mites

This study assessed the acaricidal activities of the essential oils of Litsea cubeba fruits and Mentha arvensis leaves against house dust mites, Dermatophagoides farinae and D. pteronyssinus, and stored food mite, Tyrophagus putrescentiae. The essential oil of L. cubeba fruits consisted mainly of citral (64.43%) and limonene (10.54%). In the essential oil of M. arvensis leaves, the main compounds were menthol (59.75%) and (-)-menthone (20.04%). The acaricidal activities of L. cubeba and M. arvensis oils against three types of mites were determined by a fumigant bioassay. The LD50 values of L. cubeba oil were respectively 1.54, 1.83 and 3.90 μg/cm2 and were circa 6.39, 5.01 and 3.08-fold more effective than benzyl benzoate (9.84, 9.16 and 12.01 μg/cm2) against D. farinae, D. pteronyssinus and T. putrescentiae. The LD50 values of M. arvensis oil were respectively 1.46, 1.83 and 3.41 μg/cm2 and were about 6.74, 5.01 and 3.52-fold more active than benzyl benzoate against D. farinae, D. pteronyssinus and T. putrescentiae, respectively. These results suggest that L. cubeba and M. arvensis oils may be valuable as eco-friendly acaricides for mites.

Acaricidal activity of essential oils from Lippia alba genotypes and its major components carvone, limonene, and citral against Rhipicephalus microplus

The goal of the present study was to evaluate the acaricidal potential of Lippia alba essential oil, citral chemotypes (LA-10 and LA-44 genotypes) and carvone chemotypes (LA-13 and LA-57 genotypes), as well as purified citral and enantiomers of carvone and limonene. Efficacy against Rhipicephalus microplus was assessed by the larval packet and the engorged female immersion tests. Citral chemotypes had greater larvicidal activity than carvone chemotypes, and this was further supported by larvicidal and adulticidal activity of purified citral with LC50 values of 7.0 and 29.8mg/mL, respectively. While purified enantiomers of carvone exhibited greater larvicidal activity than those of limonene, enantioselectivity of limonene was observed with R-(+) displaying significantly higher efficacy (LC50 of 31.2mg/mL) than S-(−) (LC50 of 54.5mg/mL). The essential oils and purified compounds were much less toxic toward engorged adult females, with the exception of citral, and this may be due to limited cuticular penetration.

Acaricidal activity of essential oils from five endemic conifers of New Caledonia on the cattle tick Rhipicephalus (Boophilus) microplus

The aim of the present study was to demonstrate acaricidal activity on the cattle tick Rhipicephalus (Boophilus) microplus of essential oils from endemic conifers of New Caledonia in the context of the development of natural alternatives. Acaricidal activity of essential oils extracted from resin and heartwood of five endemic conifers of New Caledonia (Araucaria columnaris, Agathis moorei, Agathis ovata, Callitris sulcata, and Neocallitropsis pancheri) was evaluated on 14- to 21-day-old Rhipicephalus microplus tick larvae using the Larval Packal Test bioassay. A first screening with 5% dilute solution was carried out and the oils with 100% of mortality at this rate were diluted until no activity was shown. The heartwood oils of the two Cupressaceae were the most active with LC50 value of 0.65% for C. sulcata and 0.55% for N. pancheri while resin oil of A. columnaris (LC50=1.62%) was the most active of the Araucariaceae family. Negative control (ethanol) was not toxic to the larvae. The chemical composition of essential oil from resin of A. columnaris was analyzed by gas chromatography-mass spectrometry. The essential oil was characterized by high level of sesquiterpene hydrocarbons and oxygenated sesquiterpenes and was composed mainly of aromadendrene (23.1%) and bicyclogermacrene (16.0%). In order to compare different plant resources in a sustainable program of natural acaricide, an "essential oil efficiency EOE" can be measured as the ratio between the yield of extraction and LC50 value. This study shows that A. columnaris (EOE=2.36) and N. pancheri (EOE=3.51) could provide valuable and effective natural acaricides for control of the cattle tick R. microplus.

Chemical composition and acaricidal activity of essential oil from Lippia sidoides on larvae of Dermacentor nitens (Acari: Ixodidae) and larvae and engorged females of Rhipicephalus microplus (Acari: Ixodidae)

The aim of this work was to identify the compounds and to investigate the acaricidal activity of the essential oil from the leaves of Lippia sidoides on Rhipicephalus microplus and Dermacentor nitens. The oil was obtained by hydrodistillation and analyzed by gas chromatography (GC/FID) and gas chromatography/mass spectrometry. In total, 15 compounds comprising 99.97 % of the total peak area were identified. The main constituent of the essential oil was thymol (67.60 %). The acaricidal activity was assessed by the modified larval packet test, with oil concentrations of 2.5, 5.0, 10.0, 15.0, and 20.0 μl/ml, and by the female immersion test with concentrations of 10.0, 20.0, 40.0, 60.0, and 80.0 μl/ml. The mortality of the R. microplus and D. nitens larvae was greater than 95 % starting at concentrations of 10.0 and 20.0 μl/ml, respectively. In the test with the engorged females, the L. sidoides essential oil starting at a concentration of 40.0 μl/ml caused a significant reduction (p < 0.05) in the values of the egg mass weight and egg production index. The viability of the eggs was affected in all the treated groups, with significantly lower hatching rates (p < 0.05) in relation to the control group. The control percentages at concentrations of 10.0, 20.0, and 30.0 μl/ml were 54, 57, and 72 %, and reached 100 % at the highest two concentrations (60.0 and 80.0 μl/ml). Therefore, it can be concluded that the essential oil from the leaves of L. sidoides has acaricidal activity on R. microplus and D. nitens.

EFFECTIVENESS OF ESSENTIAL OILS OF MEDICINAL PLANTS AGAINST STORED PRODUCT MITE, SUIDASIA PONTIFICA OUDEMANS

Acaricidal activity of essential oils obtained from 28 selected medicinal plants against stored product mite, Suidasia pontifica Oudemans, was investigated using the dry film method. The bioassay was conducted in a glass tube, 0.4 cm in diameter, 3 cm long covered with fine nylon mesh on both ends. In preliminary tests, 1.0% (53 µg cm-2) of various essential oils and 95% ethanol used as control were evaluated. Each glass tube was treated internally with 20 µl essential oils. Observations were made at 24 h after treatment and the number of dead mites was recorded. At the dose of 1.0%, essential oils of clove (Syzygium aromaticum), cinnamon (Cinnamomum bejolghota), myrtle grass (Acorus calamus), betel vine (Piper betle), and turmeric (Curcuma longa) were highly toxic to S. pontifica with more than 70% mite mortality observed at 24 h. Dry film effect of essential oils at various concentrations (0, 0.05, 0.1, 0.5, 1.0 and 1.5% equaling to 0, 2.65, 5.3, 26.5, 53 and 79.5 µg cm-2, respectively) resulting in mite mortality observed at 24 h was used to establish LD50 values. Based upon 24 h LD50 values, the essential oil of cinnamon (fresh leaf) was the most toxic to the mite with high activity at 24.05 µg cm-2, followed by essential oils of clove (dried bud), myrtle grass, cinnamon (dried bark), clove (fresh leaf), turmeric and betel vine at 24.28, 28.34, 30.89, 33.67, 38.09 and 41.76 µg cm-2, respectively.

Active compound isolated from Dioscorea japonica roots with fumigant activity against house dust and stored food mites

The acaricidal activity of essential oil from Dioscorea japonica roots against house dust and stored food mites was examined using the impregnated fumigant bioassay. The active component of D. japonica roots, isolated by silica gel column chromatography and high performance liquid chromatography, was identified as 2-hydroxy-4-methoxyacetophenone on the basis of spectroscopic analyses. Lethal dose 50 (LD50) values of 2-hydroxy-4-methoxyacetophenone were 1.29 and 1.78 μg/cm3 against Dioscorea farinae and Dioscorea pteronyssinus, respectively. The acaricidal activity of 2-hydroxy-4-methoxyacetophenone against Tyrophagus pteronyssinus was 2.28 μg/cm3. Compared to the commercial acaricide N,N-diethyl-m-toluamide (DEET), 2-hydroxy-4-methoxyacetophenone was found to be 19.52, 10.17, and 5.96 times more toxic against D. farinae, D. pteronyssinus, and T. putescentiae, respectively. These results suggest that 2-hydroxy-4-methoxyacetophenone may be useful as a preventive agent to control the growth of house-dust and stored-food mite populations.

Acaricidal effect and chemical composition of essential oils extracted from Cuminum cyminum, Pimenta dioica and Ocimum basilicum against the cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

Acaricidal activity of essential oils extracted from cumin seeds (Cuminum cyminum), allspice berries (Pimenta dioica) and basil leaves (Ocimum basilicum) were tested on 10-day-old Rhipicephalus (Boophilus) microplus tick larvae using the LPT. Two-fold dilutions of the three essential oils were tested from a starting dilution of 20% down to 1.25%. Results showed a high toxicological effect for cumin, producing 100% mortality in all tested concentrations on R. microplus larvae. Similarly, allspice essential oil produced 100% mortality at all concentrations with the exception of a dramatic decrease at 1.25% concentration. Conversely, basil essential oil was not shown to be toxic against R. microplus larvae. The most common compounds detected by gas chromatography-mass spectrometry were as follows: cumin: cuminaldehyde (22.03%), γ-terpinene (15.69%) and 2-caren-10-al (12.89%); allspice: methyl eugenol (62.7%) and eugenol (8.3%); basil: linalool (30.61%) and estragole (20.04%). Results clearly indicate that C. cyminum and P. dioica essential oils can be used as an effective alternative for R. microplus tick control, and there is a high probability they can be used for other ticks affecting cattle in Mexico and throughout the world, thereby reducing the necessity for traditional and unfriendly synthetic acaricides.

Acaricidal activity of the essential oils from Eucalyptus citriodora and Cymbopogon nardus on larvae of Amblyomma cajennense (Acari: Ixodidae) and Anocentor nitens (Acari: Ixodidae)

The present study evaluated the acaricidal activity of essential oils from Eucalyptus citriodora and Cymbopogon nardus on non-engorged larvae of Amblyomma cajennense and Anocentor nitens. In order to carry out the study, six groups were formed, each concentration being a treatment (6.25%, 12.5%, 25%, and 50%, respectively) and also with the creation of a control group (distilled water) and a positive control (Deltametrine). For each treatment, approximately 100 larvae of these ticks were placed onto filter papers (2 x 2 cm) impregnated with the concentrations used to test. Next, the envelopes were closed bearing inside the filter paper with measurements of 6 x 6 cm. For each group, six repetitions were performed, and after 24 h live and dead larvae were counted. This procedure was carried out for two essential oils on the two species of ticks. For A. cajennense, the acaricide efficacy of E. citriodora oil was of 10.8%, 35.3%, 34.5%, and 53.1%, whereas the efficacy of C. nardus was of 0.0%, 0.0%, 0.0%, and 61.1% at concentrations of 6.25%, 12.5%, 25.0%, and 50.0%, respectively. In relation to A. nitens, the acaricide efficacy of E. citriodora oil was of 20.1%, 84.5%, 89.2%, and 100.0%, whereas the efficacy of C. nardus was of 0.0%, 90.8%, 100.0%, and 100.0% at concentrations of 6.25%, 12.5%, 25.0%, and 50.0%, respectively. The results indicate that the essential oils tested showed a promising acaricidal activity mainly on A. nitens larvae.

Acaricidal activities of the essential oils from several medicinal plants against the carmine spider mite ( Tetranychus cinnabarinus Boisd.) (Acarina: Tetranychidae)

A screening for pesticidal activity of plant extracts with some known medicinal attributes could lead to the discovery of new agents for pest control. In the backdrop of recent revival of interest in developing plant-based insecticides, the present study was carried out to find an alternative to synthetic miticides currently used in the control of the devastating greenhouse pest, carmine spider mite ( Tetranychus cinnabarinus Boisd.) (Acarina: Tetranychidae). The acaricidal activities of essential oils obtained from medicinal plants such as oregano ( Origanum onites L.), thyme ( Thymbra spicata L. subsp. spicata), lavender ( Lavandula stoechas L. subsp. stoechas) and mint ( Mentha spicata L.) were evaluated against the adults of T. cinnabarinus under laboratory conditions. Chemical compositions of the essential oils were also determined by GC–MS analysis. Carvacrol was the principal compound present in the essential oils of thyme and oregano (70.93% and 68.23%, respectively), whereas α-thujone (65.78%) and carvone (59.35%) were the major constituents in lavender and mint essential oils, respectively. Volatile phase effects of different concentrations of the essential oils used were determined. Laboratory bioassay results indicated that all essential oils caused complete mortality of spider mites at different concentrations that are not phytotoxic to the host plant. Although all essential oils show acaricidal activities in a dose-dependent manner, essential oils of thyme and oregano have a marked acaricidal activity against carmine mite adults (at 5.0 and 7.5 μg ml −1 air concentrations, respectively). The mean lethal concentrations (LC 50) of the essential oils of thyme, oregano, mint and lavender were 0.53, 0.69, 1.83 and 2.92 μg ml −1 air, respectively. The results of the present study concluded that plant essential oils could be useful in promoting research aiming at the development of new agent for pest control from the plants with medicinal values.

Acaricidal Activity of Essential Oils of Chamomile, Marjoram and Eucalyptus against the Two-Spotted Spider Mite, Tetranychus urticae Koch: Biology and Enzymes

Different concentrations of three essential oil extracts (0.5, 1, 2, 3 and 4%) were used against Tetranychus urticae.(Koch) Chamomile; Chamomilla recutita (L.), proved to be the most efficient agent against T. urticae followed byMarjoram; Marjorana hortensis (L.), and Eucalyptus (Eucalyptus sp.) The LC50 values of these oils were 0.651 &1.17;1, 84 & 6.26 and 2.18 & 7.33 for adults and eggs, respectively. Herein, the bioassay experiments of the two essentialoils, Chamomile and Marjoram showed relationship between essential oil contents and activity of enzyme glutathioneS-transferase, non specific esterase and alkaline phosphatase in T.urticae. GC-MS analysis of C. recutita and M.hortensis proved the presence of 13 and 14 essential oil components, respectively. The major essential oil contents of C.recutita are α-Bisabolol oxide A (35.25%), and Trans-β-farersene (7.98%), while the main components of M. hortensisare Terpinen-4-ol (23.86%), P-cymene (23.40%) and Sabinene (10.90%). The major components of both plant extracts(Terpinen-4-ol 23.86% and α-Bisabolol oxide A 35.25% essential oils) may be responsible for the activity of enzymesof T. urticae (glutathione S-transferase, non specific esterase and alkaline phosphatase).