Acaricidal Properties Research Articles

Toxic effects of avermectin on liver function, gut microbiota, and colon barrier in the rat model

Avermectin (AVM), a compound derived from the fermentation of Avermectin Streptomyces, has insecticidal, acaricidal, and nematicidal properties. Widely employed in agriculture, it serves as an effective and broad-spectrum insecticide for pest control. Although the toxicity of AVM at low doses may not be readily apparent, prolonged and extensive exposure can result in poisoning. To investigate the toxic effects of AVM on the body, this study established rat models of AVM poisoning with both low and high concentrations of the compound. Fifteen male rats were randomly assigned to one of three groups (n=5 per group): a control group, a low-concentration group, and a high-concentration group. The low-concentration group was administered an oral dose of 2 mg/kg AVM once daily for a duration of seven days, while the high-concentration group received an oral dose of 10 mg/kg AVM once daily for the same period. This study examined the impact of AVM on liver function and gut microbiota in rats using weight monitoring, liver function indicator detection, liver metabolomics sequencing, colon barrier function testing, and gut microbiota sequencing. The findings of this study demonstrated that exposure to 2 or 10 mg/kg AVM for seven days can lead to a notable decrease in rat weight, as well as induce liver dysfunction and metabolic disturbances. Additionally, AVM exposure can disrupt the composition of the intestinal microbiota and impair the integrity of the colon mucosal barrier, causing downregulation of Occludin expression and upregulation of inflammation-related protein expression levels such as IL-1β, Myd88, and TLR4. Furthermore, bioinformatics analysis revealed a significant association between liver dysfunction and dysbiosis of the gut microbiota. These findings have implications for the agricultural use of AVM and its potential contribution to environmental pollution. Consequently, individuals involved in AVM usage should prioritize safety precautions and monitor liver function.

Evaluation of acaricidal activity in entomopathogenic fungi for poultry red mite (Dermanyssus gallinae) control

The poultry red mite (PRM), Dermanyssus gallinae, significantly impacts the health of egg-laying hens. Mites feed on the blood of infested chickens and have a great economic impact on the poultry industry. Chemical treatment of mites raises concerns about their resistance to miticides and residues in eggs and poultry. Biocontrol using entomopathogenic fungi is expected to be a chemical-free strategy for reducing PRM infestations. Therefore, the present study aimed to investigate the effects of various entomopathogenic fungal species collected in South Korea on the inhibition of PRM. Seventeen strains of six fungal species collected from various sources were used to evaluate acaricidal activity against PRM. The results showed that 16/17 strains had acaricidal properties against PRM, of which strains of Metarhizium anisopliae had the highest acaricidal activity. Mites treated with M. anisopliae CBNU 4–2 showed 100 % mortality 5 d after inoculation, followed by M. flavoviride var. pemphigi. The M. flavoviride var. pemphigi CBNU 1–1–1 showed 97.78 % mortality after 10 d of exposure to fungi. The mortality rate of PRM treated with other strains slowly increased and reached its highest value on the 14th day of inoculation. The results of this study provide information on the acaricidal activity of different entomopathogenic fungi against PRM. This information is important for the selection of fungal species for developing biocontrol methods for PRM treatment. These strains could be used for further evaluation of PRM treatment on chicken farms, or in combination with other methods, to increase PRM treatment efficiency.

Acaricidal properties of Corsican Humulus lupulus L. (Cannabaceae) essential oils against Varroa destructor: a honeybee health perspective

ABSTRACT Six Corsican essential oils (EOs) from Humulus lupulus were studied for their activity against Varroa destructor adults and Apis mellifera pupae. The GC/MS analysis of EOs showed that the major compounds of all accessions were α-Humulene, Myrcene, α-Selinene, β-Selinene, (E)-β-Farnesene, and (E)-β-Caryophyllene. Bioassays showed that EOs from each accession acted as toxins and repellents against V. destructor adults, with lower toxicity towards A. mellifera pupae. In terms of efficacy against V. destructor adults, Smaragd 2020 oil displayed the highest performance, with LC50 and LC90 values of 2.33 and 7.83 µL/L air, respectively. Meanwhile, Smaragd 2019 and Tettnanger EOs showed moderate toxicity, with LC50 values of 3.101 and 3.66 µL/L air, along with LC90 values of 11.67 and 19.89µL/L air, respectively. The oils from Biguglia and Ajaccio were strongly repellent to Varroa adults. At the lowest concentration (2 µL/mL), these EOs exhibited percentage of repellence greater than 70% after 2h exposure, with RC50 values of 1.66 and 1.26 µL/L air, respectively. Concerning their insecticidal effects, EOs demonstrate reduced toxicity towards bee pupae when compared to Varroa mites. Notably, Ajaccio stands out for inducing lower mortality among bee pupae, with a selectivity ratio below 2 and LC50 of 11.25 µL/L air.

Assessing the Impact of Abamectin and Diafenthiuron on Silkworm Larval Growth and Survival

An experiment was conducted primarily to evaluate chemicals exhibiting dual insecticidal and acaricidal properties, with a specific focus on their compatibility with silkworms and indigenous natural predators within the mulberry ecosystem, to evaluate abamectin 1.9% EC and diafenthiuron 50% WP for safety period on mulberry silkworm, Bombyx mori L. (Jan-Feb and Mar-April 2023) where in the pesticides were sprayed on mulberry at different durations, after spray were fed to the silkworms from third instar onwards. There was no mortality (0.00%) of silkworm observed in the treatments during two seasons and the larval progression 100% during third, fourth and fifth instars. The total larval duration was found shortest when the silkworms were fed with mulberry leaves harvested from the plots sprayed with abamectin 1.9% EC at 0.75ml/lit (22.30 and 23.22 days) and diafenthiuron 50% WP at 1 g/lit (22.77 and 23.07 days) at 15 and 21 DAS, respectively. The larval weight was significantly maximum in the treatments with abamectin 1.9% EC at 0.75 ml/lit (4.29 and 4.08 g/larvae) and diafenthiuron 50% WP at 1 g/lit (4.17 and 4.06 g/ larvae), respectively at 15 and 21 DAS. The Effective Rate of Rearing (ERR %) was found highest with diafenthiuron 50% WP at 1 g/lit (97.78 and 96.67 % at 15 and 21 DAS) and abamectin 1.9% EC at 0.75 ml/lit (97.78 and 96.67 % at 15 and 21 DAS) that was comparable with control. The molecules, diafenthiuron 50% WP at 1 g/lit and abamectin 1.9% EC at 0.75 ml/lit were found safer to silkworms at 15 and 21 DAS in terms of survival and larval growth.

Comparative analysis of essential oil efficacy against the Asian longhorned tick Haemaphysalis longicornis (Acari: Ixodidae).

This study evaluated the potential repellent and acaricidal effects of 4 essential oils (clove, eucalyptus, lavender, and mint) against the Asian longhorned tick Haemaphysalis longicornis, a vector of various tick-borne diseases in medical and veterinary contexts. Selected for their potential repellent and acaricidal properties, the 4 essential oils were tested on adult and nymph H. longicornis ticks at different concentrations. The experiment assessed mortality rates and repellency, particularly during tick attachment to host skin. There was a significant increase (p<0.05) in tick mortality and repellency scores across all groups. At a 1% concentration, adult tick mortality ranged from 36% to 86%, while nymph mortality ranged from 6% to 97%. Clove oil exhibited notable efficacy, demonstrating high mortality rates of nymphs and adults. Clove oil also displayed strong repellency properties, with a repellency index of 0.05, surpassing those of mint, eucalyptus, and lavender oils. Clove oil showed the highest effectiveness in deterring nonattached adult ticks (90%) and nymphs (95%) when applied to skin. Clove oil was the most effective against adult and nymph ticks, achieving mortality rates of 86% and 97%, respectively, and led to the highest nonattachment rates when applied to skin. In conclusion, essential oils such as clove, eucalyptus, lavender, and mint oils present promising results for tick population control.

ITRAQ-based proteomics revealed the acaricidal mechanism of methyl isoeugenol against Dermatophagoides farinae

ABSTRACT Dermatophagoides farinae is a major source of allergens that are the cause of allergic diseases in humans. Methyl isoeugenol (MIE) is a naturally occurring compound in plants and its strong acaricidal toxicity has been established; however, the mechanism behind its acaricidal properties remains unclear. In this study, to investigate the action mechanism of MIE on D. farinae the isobaric tags for relative and absolute quantification (iTRAQ) proteomics method is used. Protein samples were extracted from D. farinae before and after 24 h of MIE treatment for iTRAQ technique analysis. Bioinformatics analysis revealed that most differentially expressed proteins were located in the cytoplasm, impacting cytoplasmic function. Additionally, Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed significant enrichment of the differential proteins in the cellular autophagy signalling pathway. The autophagy-related proteins Autophagy-Related Protein 3 (ATG3) and Cathepsin L (CTSL) were up-regulated, disrupting the autophagic process. We found that the main action mechanism of MIE against D. farinae might be cellular autophagy. The transcriptional validation of six differential proteins demonstrated consistent expression trends with the proteomics data. This study reveals the acaricidal mechanism of MIE for the first time and lays the foundation for further research on D. farinae control.

Lime for Lyme: Treatment of Leaf Litter with Dolomitic Lime Powder Impairs Activity of Immature Ixodes scapularis Ticks.

Background: Tick-borne diseases are an emerging threat to public health throughout the temperate world, leading to a growing field of research aimed at developing and testing intervention strategies for reducing human-tick encounters or prevalence of infection in ticks. Various wide-spectrum chemical acaricides have proven effective for controlling tick populations, but many of these have potential deleterious side-effects on health and the environment. In addition to chemical acaricides, certain compounds such as diatomaceous earth have been shown to have physical acaricidal properties. We hypothesized that dolomitic lime (CaMg(CO3)2, a corrosive, desiccant mineral that is already used extensively in agricultural and forestry contexts to balance the pH of soils, may affect ticks' locomotory activity, habitat position, or survival and that this should manifest as a reduction in the number of questing ticks collected by dragging. Objective: This study aimed to formally assess this hypothesis in a controlled laboratory setting. Methods: We carried out a microcosm experiment, with one control and three treated microcosm trays, each replicating the natural substrate characterizing I. scapularis habitat in northeastern North America. Each tray was infested with 200 living larvae and 50 nymphs, and then treated with 0 (control), 50, 100, or 500 g/m2 of lime powder. Ticks were collected by microdragging 24 and 72 h postliming. Results: Efficacy of liming at reducing the number of collected questing ticks ranged from 87% to 100% for larvae and 0% to 69% for nymphs 24 h postliming and from 91% to 93% for larvae and -47% to 65% for nymphs 72 postliming. Conclusion: This study provides the first experimental evidence of the potential efficacy of liming for impairing activity of questing immature ticks. Given that lime is a low-cost material, that methods for widespread application in deciduous woodlands already exist, and that it has been documented as having a limited negative impact on the environment, further assessment of lime application as a public health risk reduction intervention for tick-borne diseases is warranted.

Assessment of cattle tick infestation: Molecular insights into Rhipicephalus annulatus and the efficacy of garlic oil and nanoemulsion as acaricidal agents

Ticks, particularly Rhipicephalus annulatus, pose significant threats to livestock, causing economic losses and transmitting various infectious diseases. This study aimed to evaluate the potential acaricidal properties of garlic oil and its nanoemulsion against ticks infesting cattle, Rhipicephalus annulatus through the evaluation of mortality rate and morphological changes of the treated ticks. The study also included prevalence, risk factors, and molecular confirmation of tick species. Genetic characterization confirmed the identity of R. annulatus. Our results revealed a high prevalence of R. annulatus (46.9%) with a higher risk in male cattle (50%) than females (44.9%) and a nonsignificant high infection (49.1%) in animals ≤ 1 year old. The acaricidal efficiency of garlic oil and its nanoemulsion was concentration and time-dependent. The high concentration of garlic oil (20 mg/L) induced complete mortality within 48 hours. The nanoemulsion formulation enhanced efficacy, particularly at 5 mg/L, which exhibited rapid and substantial acaricidal activity. Scanning electron microscopy revealed morphological alterations induced by garlic oil and its nanoemulsion, including changes to the anterior capitulum, dorsal, and ventral cuticles. The study contributes to the exploration of effective, safe, and eco-friendly alternatives for tick control. Further research is warranted to validate their efficacy under diverse conditions and assess practical strategies.

Assessment of the in vitro acaricidal activity of Bravecto® (fluralaner) and a proposed orange oil-based formulation vehicle for the treatment of Sarcoptes scabiei

BackgroundSarcoptic mange is a serious animal welfare concern in bare-nosed wombats (Vombatus ursinus). Fluralaner (Bravecto®) is a novel acaricide that has recently been utilised for treating mange in wombats. The topical ‘spot-on’ formulation of fluralaner can limit treatment delivery options in situ, but dilution to a volume for ‘pour-on’ delivery is one practicable solution. This study investigated the in vitro acaricidal activity of Bravecto, a proposed essential oil-based diluent (Orange Power®), and two of its active constituents, limonene and citral, against Sarcoptes scabiei.MethodsSarcoptes scabiei were sourced from experimentally infested pigs. In vitro assays were performed to determine the lethal concentration (LC50) and survival time of the mites when exposed to varying concentrations of the test solutions.ResultsAll compounds were highly effective at killing mites in vitro. The LC50 values of Bravecto, Orange Power, limonene and citral at 1 h were 14.61 mg/ml, 4.50%, 26.53% and 0.76%, respectively. The median survival times of mites exposed to undiluted Bravecto, Orange Power and their combination were 15, 5 and 10 min, respectively. A pilot survival assay of mites collected from a mange-affected wombat showed survival times of < 10 min when exposed to Bravecto and Orange Power and 20 min when exposed to moxidectin.ConclusionsThese results confirm the acaricidal properties of Bravecto, demonstrate acaricidal properties of Orange Power and support the potential suitability of Orange Power and its active constituents as a diluent for Bravecto. As well as killing mites via direct exposure, Orange Power could potentially enhance the topical delivery of Bravecto to wombats by increasing drug penetration in hyperkeratotic crusts. Further research evaluating the physiochemical properties and modes of action of Orange Power and its constituents as a formulation vehicle would be of value.Graphical

Evaluation of the acaricide activity of extracts from eight species of medicinal plants on larvae of Hyalomma anatolicum (Acari: Ixodidae) ticks

The tick Hyalomma anatolicum is the principal species of hard tick that impairs ruminants’ productivity in Iran. The purpose of this study is to evaluate the acaricide activity of eight products of plant origin. The ethanolic extract of Achillea millefolium, Ailanthus altissima, Rosmarinus officinalis, Eucalyptus camaldulensis, Lavandula angustifolia, Mentha piperita, Nicotiana tobacum leaves, and Allium sativum cloves were investigated at four concentrations (25, 50, 100, and 200 mg/ml) against H. anatolicum larvae. The modified “larval packet test” was performed on approximately 100 larvae of H. anatolicum at 14–21 days of age. At the highest concentration (200 mg/ml), the larval mortality was 100, 65.00, 46.66, and 43.33 % for N. tobacum, A. sativum, Ac. millefolium, and L. angustifolia extracts, respectively, showing higher mortality than at the lowest concentration. Ai. altissima and R. officinalis extracts had no considerable effect on the mortality percentages of larvae (21.33 %) at the highest concentration. The results show that the extracts of N. tobacum leaves and A. sativum cloves have good acaricidal properties and merit further investigation as alternative approaches to control the H. anatolicum tick.

Screening of volatile compounds of essential oils with acaricidal activity in Rhipicephalus microplus larvae using a new in vitro evaluation method

ABSTRACT The study assessed the acaricidal properties of 20 compounds derived from essential oils against the Rhipicephalus microplus tick, a significant menace to tropical livestock with considerable economic losses. A novel methodology was devised, involving the determination of mortality times for R. microplus larvae upon direct contact with these compounds. Mortality times were compared against a negative control (soybean oil) and two positive controls (commercial pour-on products). Tests were conducted in 48-well polyethylene plates, with around 100 larvae immersed in 200 µl of oil (at a 100% dose). The 10 compounds exhibiting the shortest mortality times were subsequently diluted in soybean oil at varying concentrations. Notably, thymol exhibited potent acaricidal activity, with the lowest effective dose (1.56%) resulting in larval mortality within 15 minutes, whereas positive controls necessitated over 66 minutes. A correlation was established between the molecular structure of the compounds and their acaricidal efficacy, indicating that cyclic compounds containing 10 carbon atoms demonstrated heightened lethality compared to acyclic counterparts. This innovative methodology enables the rapid identification of substances with substantial acaricidal potential in vitro, yielding results within minutes, in stark contrast to the traditional larval immersion test, which demands a minimum of 24 hours for conclusive outcomes.

Laboratory assessment of the acaricidal, repellent and anti-cholinesterase effects of Melaleuca alternifolia and Chamaemelum nobile essential oils against Hyalomma scupense ticks.

In cattle, Hyalomma scupense serves as an important vector of several pathogens resulting in diseases, subsequently affecting the agricultural field as well as the economy. Resistance to chemical acaricides has become widespread affirming the need for new drugs to tick control. The goal of this study was to investigate the acaricidal, repellent activities as well as the putative mode of action of two essential oils (EOs) from Melaleuca alternifolia (Tea tree) and Chamaemelum nobile (Roman chamomile) on Hyalomma scupense. The chemical composition of EOs was also evaluated. Different concentrations of EOs were tested in vitro for their acaricidal property on adults and larvae of H. scupense using adult immersion test (AIT) and larval packet test (LPT). Additionally, using Ellman's spectrophotometric method, the anticholinesterase (AChE) inhibition activity of M. alternifolia and C. nobile EOs was assessed in order to understand their putative mode of action. The main compounds of C. nobile were α-Bisabolene (22.20%) and (E)-β-Famesene (20.41%). The major components in the analyzed M. alternifolia were Terpinen-4-ol (36.32%) and γ-Terpinene (13.69%). Adulticidal and larvicidal assays demonstrated a promising efficacy of the essential oils against tick H. scupense. The lethal concentration (LC50) values obtained for M. alternifolia and C. nobile oils were 0.84 and 0.96 mg/mL in the AIT and 0.37 and 0.48 mg/mL in the LPT, respectively. Regarding repellent activity, M. alternifolia achieved 100% repellency at the concentration of 1 mg/mL while C. nobile showed 95.98% repellency activity at concentration of 4 mg/mL. Also, M. alternifolia and C. nobile EOs displayed potent AChE inhibition with IC50 value of 91.27 and 100.12 μg/mL, respectively. In the present study, M. alternifolia and, to a lesser degree, C. nobile EOs were found to be effective in vitro acaricides, repellents and acetylcholinesteraseinhibitor against H. scupense ticks. These plants may represent an economical and sustainable alternative to toxic synthetic acaricides in the management of ectoparasites of veterinary importance.

The efficacy of clove oil to manage Varroa destructor and Apocephalus borealis, in Apis mellifera L. colony

Clove oil is a natural, eco-friendly, and highly effective odorant for triggering hygienic behavior in the colonies of Apis mellifera. Bees with highly hygienic behavior can quickly remove Varroa destructors and other enemies of bee hives. The estimation of hygienic behavior is estimated by a pin-killed method. 24 hours of experiments were conducted for observation at different months. Observed significant difference at 3 hours (P ˂ 0.001) and a non- significant difference at 6,9 and 24 hours (P &gt; 0.09), (P &gt; 0.014,) and (P &gt;0.5) for the opened cells. For the cleared cells there has been observed significant difference at 3 and 6 hours (P ˂ 0.03) and (P ˂ 0.04), non- significant difference at 9 and 24 hours (P &gt; 0.25) and (P &gt; 0.012). clove oil also has acaricidal properties which is very effective in controlling Varroa mites and other parasites of honey bees. For the trapping of Varroa destructor and Apocephalus borealis, the sticky board method was used, in which a petroleum jelly-coated sheet was inserted at the bottom board for the trapping of mites and flies can be controlled within a week, highly significant differences observed in the first 3 days, P-values are respectively (P ˂ 0.00013), (P ˂ 0.0011), and (P ˂ 0.01), on the fifth, sixth and seventh day no significant difference discern. Mites could control within 40 days, there has been no significant difference between the first and last week, and notice a significant difference between the second and third week (P ˂ 0.0025).

Effect of Tagetes minuta essential oil on the central nervous system of unfed Rhipicephalus sanguineus sensu lato 'tropical lineage' ticks.

Rhipicephalus sanguineus sensu lato 'tropical lineage' (Acari: Ixodidae) is considered a sanitary concern due to its role as a disease vector. Tick strains resistant to synthetic acaricides have caused difficulties in their control, besides synthetic acaricides are harmful to the environment and to the health of non-target animals. The research of plants with acaricidal and repellent properties has proved to be an efficient alternative in tick control. The genus Tagetes spp. excels for its use as traditional pest control in households and plantations and also for its potential as an acaricide against R. sanguineus under laboratory conditions. The first aim of the present study was to evaluate the effect of different doses of Tagetes minuta essential oil (TMEO) on the central nervous system (synganglion) in unfed R. sanguineus adults. The histological analysis of synganglion exposed to the different concentrations of TMEO and amitraz 12.5% (50% of the recommended dose in the package insert) showed a significant effect with signs of cell damage including volume increase, loss of shape, and vacuolization, in addition to chromatin alterations such as condensation, margination, and fragmentation. TMEO were analyzed by gas chromatography coupled with mass spectrometry showing the presence of 21 compounds that according to their chemical structure are classified as terpenoids. Among them (Z)-β-ocimene, ocimene, (Z)-tagetone, and verbenone were found in major quantities.

Acaricidal and insecticidal activity of essential oils obtained from the aerial parts of three Mexican Bursera species

In search of new sustainable biopesticides, we determined the phytochemical profiles, acaricidal and insecticidal properties of EOs distilled from the aerial parts of three Mexican Bursera species. Results were obtained by GC–MS analysis and three different bioassays, indicating that the EO of Bursera glabrifolia exhibited high relative abundancies of α-pinene, β-myrcene, and α-phellandrene, as well as promising pesticidal activity against Spodoptera littoralis larvae (LD50,90 = 32.4, 107.2 µg/larva), and Musca domestica (LD50,90 = 23.2, 103.2, and 13.5, 77.4 µg/female or male adult, respectively) and Tetranychus urticae adults (LD50,90 = 7.4, 30.3 µg/cm2). The Bursera lancifolia and Bursera linanoe samples contained mainly D-limonene or linalyl acetate and linalool, respectively, and showed generally less potent pesticidal properties (S. littoralis larva, LD50,90 = 45.4, 154.4 and 52.2, 158.7 µg/larva, respectively; female M. domestica adult, LD50,90 = 69.2, 210.9 and 45.1, 243.8 µg/female adult, respectively; T. urticae adults, LD50,90 = 20.7, 90.5 and 17.5, 71.4 µg/cm2, respectively). However, the EO of B. linanoe exhibited an especially pronounced activity against male M. domestica adults (LD50,90 = 10.6, 77.2 µg/male adult). Our findings prove the pesticidal potential of Mexican Bursera species in the context of integrated pest management (IPM) and highlight the importance of conducting further research to elucidate both the active principles and possibly existing synergistic effects.

Acaricidal effects of two native isolates of entomo-pathogenic bacteria Photorhabdus luminescens (Thomas & Poinar) against spider mite, Tetranychus truncatus Ehara (Acari: Tetranychidae)

ABSTRACTTwo local isolates of P. luminescens (NCBI GenBank Accession numbers ON627692, and ON627695) were evaluated for their bio-efficacy against the spider mite Tetranychus truncatus in the laboratory. Different concentrations (104 to 108 CS/CFS mL−1) of cell suspension (CS) and cell-free supernatant (CFS) of the bacterial isolates obtained by centrifugation (4000 rpm for 20 min) were topically applied on eggs and adults of spider mites. The observations on ovicidal as well as adulticidal activity of bacterial isolates were recorded at 24, 48, and 72 h intervals. The bacterial isolates showed significant ovicidal and adulticidal properties for both CS and CFS after 72 h of treatment application. The isolate CNT1 recorded 84.00 and 58.67% mortality of eggs and 100 and 97.33% mortality of adults, respectively, for CS and CFS, at 108 mL−1 concentration. At the same concentration, the isolate ODA showed 44.00 and 84.00% mortality of eggs and 98.67 and 100% mortality of adults, respectively, for CS and CFS. The study identified two bacterial isolates of P. luminescens with appreciable acaricidal properties that can be exploited as a potential biocontrol agent against spider mite pests of crops.

Role of phytochemicals and secondary metabolites from Mentha spicata in acetylcholine esterase inhibition for effective pest control of Tetranychus urticae Koch

ABSTRACTThe two-spotted spider mite (Tetranychus urticae Koch) poses a significant threat to global food production. However, the environmental risks associated with synthetic pesticides have necessitated the exploration of eco-friendly alternatives. Plant-based biopesticides utilizing secondary metabolites have emerged as promising strategies for pest management. This study aimed to extract and characterize Mentha spicata L. through biochemical analyses, GC-MS, and LC-QTOF-MS. The extract’s acaricidal, oviposition deterrence, and repellent properties were evaluated against Tetranychus urticae, revealing a pronounced time- and concentration-dependent effect over 96 hours, with an LC50 of 3 µg/mL. Furthermore, the impact of the extract on plant growth was assessed using tomato plants, demonstrating an enhancement in growth rate based on photosynthesis, weight, and oxidative stress markers analyses. Polyphenolics and terpenoids in M. spicata were identified as contributors to its biological activities, including antioxidant and free-radical scavenging properties. Molecular docking experiments targeting acetylcholine esterase (AChE) were conducted on the identified phytocompounds, indicating a high affinity for δ-3-Carene and Isoferuloyl C1 glucuronide. The pesticidal effects of these compounds were attributed to their competitive and synergistic inhibition of AChE. These findings highlight the potential of plant extracts, specifically M. spicata, as effective biopesticides in future pest control strategies. The utilization of secondary metabolites from plant sources offers a sustainable and environmentally friendly approach to combatting T. urticae infestations.

Evaluation of synergism in essential oils against the cattle tick Rhipicephalus microplus in Burkina Faso

The cattle tick Rhipicephalus microplus affects animal production economically by reducing weight gain and milk production and causing diseases, such as babesiosis and anaplasmosis. Using synthetic acaricides to reduce their incidence has caused the emergence of resistant tick populations. The present study aimed to assess the in vitro acaricidal activity of combinations of essential oils (EOs) from Ocimum americanum, Ocimum gratissimum, and Lippia multiflora against R. microplus larvae. In fact, numerous biological properties have been reported on EOs from these three plants, including acaricidal properties. Hence, a larval immersion test was performed using a population of R. microplus resistant to synthetic acaricides used in Burkina Faso. Results revealed that EO from O. gratissimum was the most effective on R. microplus larvae with LC50 and LC90 values at 10.36 and 15.51 mg/mL, respectively. For EO combinations, the most significant synergistic effect was obtained by combination 6 (1/3 O. americanum + 2/3 O. gratissimum +1/6 L. multiflora), with a combination index value of 0.44. All combinations presented dose reduction index >1, indicating a favorable dose reduction. According to the literature, this is the first study to determine the combination effect of EOs from the abovementioned plants in controlling R. microplus activity in vitro. Thus, the combination of these EOs is an alternative to control the resistant populations of invasive cattle ticks.

Computational, chemical profile and in vitro acaricidal property of methanol and chloroform extracts of Cymbopogon citratus Stapf leaf

This study investigated the phytochemical composition, antioxidant and acaricidal properties of methanol and chloroform extracts of Cymbopogon citratus leaf. A known quantity of the pulverized plant material was first exhaustively extracted with chloroform and thereafter, with methanol using a Soxhlet apparatus set at 40 °C. The extracts were concentrated in a hot air oven at 40 °C. Gas chromatography-mass spectroscopy was used to determine the phytochemical composition, while 1,1 diphenyl-2-picrylhydraxyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) assay were used to evaluate the antioxidant profile of the extracts at concentrations of 25 - 400 µg/mL. Contact method was used to investigate the acaricidal property and molecular docking analysis of selected identified compounds were performed against acetylcholinesterase to check their drug like potentials. Fifty-seven and sixty-four compounds were identified in the methanol and chloroform extracts, respectively. The methanol extract produced higher antioxidant and acaricidal properties (P &lt; 0.05) relative to the chloroform extract. The compounds formed hydrogen bonds with amino acid residues. In conclusion; the methanol extract demonstrated better antioxidant and acaricidal properties than the chloroform extract, which could be linked to the higher concentration of essential oil (Carvomenthol, (-)-carvone, and eucalyptol) in the methanol extract.

Natural Products as Mite Control Agents in Animals: A Review.

Mites have been a persistent infectious disease affecting both humans and animals since ancient times. In veterinary clinics, the primary approach for treating and managing mite infestations has long been the use of chemical acaricides. However, the widespread use of these chemicals has resulted in significant problems, including drug resistance, drug residues, and environmental pollution, limiting their effectiveness. To address these challenges, researchers have shifted their focus towards natural products that have shown promise both in the laboratory and real-world settings against mite infestations. Natural products have a wide variety of chemical structures and biological activities, including acaricidal properties. This article offers a comprehensive review of the acaricidal capabilities and mechanisms of action of natural products like plant extracts, natural compounds, algae, and microbial metabolites against common animal mites.