Search Results (297)

Carvacrol derived from Origanum vulgare oil was evaluated for its acaricidal efficacy and mechanism of action against Haemaphysalis longicornis, a primary vector of severe fever with a thrombocytopenia syndrome. Essential oils extracted from O. vulgare leaves cultivated in Germany, Albania, and Iran were analyzed. Among them, the German oil exhibited the highest acaricidal potency due to its elevated carvacrol content (83.38%). Carvacrol was isolated and its identity was confirmed using GC/MS, NMR, and FT-IR analyses. Carvacrol demonstrated significant toxicity across all developmental stages of H. longicornis, with LC₅₀ values of 3.47, 8.21, and 15.27 μg/cm³ for larvae, nymphs, and adults, respectively—representing 4.4-, 3.5-, and 3.2-fold higher potency compared to diethyltoluamide. The acaricidal mechanism of carvacrol involved multiple pathways: (i) inhibition of acetylcholinesterase activity by up to 85.4%, leading to neural disruption; (ii) suppression of cytochrome P450 monooxygenases (47.4% reduction), α-esterase (24.8% reduction), and β-esterase (28.6% reduction); and (iii) disruption of neural signaling pathways critical for survival. Chemical analysis confirmed carvacrol as the predominant active component in O. vulgare oil, with additional contributions from thymol and thymoquinone. Although its concentration in Iranian oil was lower, thymoquinone demonstrated the highest acaricidal potency (4.98 μg/cm³). Nevertheless, the abundance and superior efficacy of carvacrol establish it as the primary component contributing to the oil’s bioactivity. This study demonstrates that carvacrol is a promising eco-friendly alternative to synthetic acaricides for the control of H. longicornis. Its ability to inhibit acetylcholinesterase activity and suppress detoxifying enzymes suggests potential for overcoming resistance mechanisms associated with synthetic chemicals. Further studies should focus on optimizing the formulations and applying them in the field to improve efficacy. Full article

Background/Objective: Anti-tick vaccines represent a promising alternative to chemical acaricides for the management of ticks on wildlife; however, little progress has been made to produce a vaccine effective in wild hosts that are critical for tick reproduction, such as the white-tailed deer (Odocoileus virginianus). We recently tested Amblyomma americanum salivary and midgut extracellular vesicles as vaccine candidates in white-tailed deer, which resulted in on-host female tick mortality. The objective of this study was to identify the proteins recognized by the antibodies regenerated during these vaccinations to determine potential antigens for vaccine development for white-tailed deer. Methods: Using a proteomic approach, we characterized the cargo within salivary and midgut vesicles. Label-free quantitative proteomics were used to investigate significant changes in protein loading within extracellular vesicles in these two organs. The pre-vaccination and post-vaccination serum from three animals vaccinated with salivary and midgut vesicles and one control animal were used to identify proteins recognized by circulating antibodies. Results: We show that these salivary and midgut vesicles contain a “core-cargo” enriched in chaperones, small GTPases, and other proteins previously reported in small EVs. Label-free quantitative proteomics show significant differences in protein cargo between salivary and midgut vesicles (333 proteins out of 516). Proteomic analysis of immunoprecipitated proteins identified thirty antigens with potential for use in anti-tick vaccines, seven of which we have categorized as high priority. Conclusions: Proteins within tick salivary and midgut vesicles are recognized by antibodies from vaccinated white-tailed deer. These proteins can be further evaluated for their function and potential as vaccine candidates against ticks. Full article

Different inert materials have been tested as grain protectants against stored-product mites with variable results. Most of the studies are focused on the efficacy of diatomaceous earth, but there are few comparable data on other types of inert dust. In this study, we have tested two inert materials, zeolite and kaolin, against the cheese mite Tyrophagus putrescentiae (Schrank) (Astigmata: Acaridae) on wheat. Mites were reared in the laboratory under controlled conditions of 25 °C and 80% relative humidity. Bioassays were conducted to assess the acaricidal effects of zeolite and kaolin. These formulations were applied to wheat kernels at 100, 500, and 1000 ppm. The treated wheat was manually mixed and divided into 1 g subsamples, each containing ten T. putrescentiae. Mortality was recorded after 3 and 7 days, while progeny production was assessed after 42 days. Control samples without treatment were also included, and all experiments were conducted under the same controlled conditions. Our results indicated that zeolite was more effective than kaolin, regardless of the dose rates tested. Parental mortality reached 100% on wheat treated with 1000 ppm of zeolite after only 3 days of exposure. In contrast, survival of T. putrescentiae was noted in all doses of kaolin. Moreover, progeny production in the treated substrate was not avoided even in the highest dose of kaolin but was totally (100%) suppressed at 500 and 1000 ppm. Our results illustrate that zeolite was very effective for the control of this species, even at short exposure intervals, and hence, can be considered further as a grain protectant. Full article

Ticks pose one of the key economic risks to the cattle industry globally, affecting productivity, health, and welfare. Over 80% of the cattle population around the globe is affected by tick infestation. Several tick control methods, including the use of chemical acaricides, herbal agents, and some complementary measures, like the use of old motor oil, disinfectant, pour-on, tick grease, pulling off, cutting, paraffin, and Jeyes fluid, have been used by farmers to alleviate the effects of hematophagous ticks. However, these strategies are often mistakenly employed and can harm animals. Likewise, these methods cannot be sustained because of their cost, environmental impact, flaws, and resistance. An abundantly available, cost-effective, environmentally friendly, and naturally occurring substance like fossil shell flour with no known side effects could present a sustainable solution. This review abridged the research and information on hematophagous tick control in South African cattle production using fossil shell flour. This is a systematic review of the published literature and catalogues. All available documented evidence on this topic was collated and synthesized through standardized methods of systematic review protocol. Different scientific studies and a few references from farmers’ magazines published from 1941 to 2022 were reviewed. Out of 120 research papers downloaded, 98 were included and analyzed directly or indirectly regarding hematophagous tick control in cattle production and the use of fossil shell flour among livestock farmers. The advancement in ectoparasite control through fossil shell flour is a novel concept that needs to be explored for the benefit of all livestock farmers, hence this review. Fossil shell flour has been shown to have good insecticidal effectiveness against insects of animal and agricultural importance. We hereby recommend the exploration of FSF as an alternative tick control measure to the currently used acaricides to which ticks have developed resistance. Full article

Double-stranded RNA (dsRNA) biopesticides offer the potential for highly targeted pest control with minimal off-target impacts. Varroa mites (Varroa destructor) are an important pest of honey bees (Apis mellifera) that are primarily managed by synthetic pesticides. A next-generation treatment using a varroa-active dsRNA, vadescana, has been developed to target calmodulin expression in varroa. We evaluated the potential exposure of non-target species to vadescana. First, we assessed potential gene silencing effects on 39 arthropods with known genomes via bioinformatics. Three mite species, monarch butterflies (Danaus plexippus), fruit flies (Drosophila melanogaster), and European earwigs (Forficula auricularia) showed theoretical potential for off-target effects. These in silico results could be used to help inform risk assessments. Second, we conducted vadescana feeding trials on the greater wax moth (Galleria mellonella), a common beehive associate. There were no significant differences in wax moth reproduction, survival, or adult F2 wing length between vadescana-fed and control groups. Male F2 body weight was slightly but significantly lower in wax moths exposed to the highest vadescana dose, with no such effect observed in female moths. Calmodulin gene expression was unaffected in wax moths. Our hazard assessment of vadescana’s lethal and sublethal effects on wax moths indicates minimal impact following continuous dietary exposure far greater than any exposure that might be expected in the field, in line with the bioinformatics findings. This biopesticide appears highly varroa-specific and likely has fewer non-target effects than many current varroa control methods. Full article

Varroa destructor is an ectoparasitic mite that causes a true syndrome with complex symptoms in honeybees. For mite control, several synthetic active principles are commercially available. However, these formulations are proving less effective due to the acquisition of resistance mechanisms by the parasite. Naturally derived compounds, such as essential oils, are less prone to generating resistance mechanisms in mite populations and have been proven effective in numerous independent laboratory investigations. In this study, semi-field and field tests were conducted to evaluate the acaricidal efficacy of two essential oils (Citrus bergamia and Citrus limon), which, in our previous residual contact toxicity tests, showed efficacy against Varroa mites. For semi-field cage tests, two-level cages were set up. Filter paper soaked with different concentrations of essential oils was placed in the lower compartment of the cage; 20 honeybees and 10 Varroa mites were allocated in the upper level. Mite detachment from the honeybees was evaluated after 24 and 48 h. For field tests, cardboard strips soaked with solutions of essential oils at different concentrations were inserted in the experimental hives. Weekly, the strips were replaced, and the fall of parasites on the diagnostic bottom board was assessed. Semi-field tests showed that the essential oils, at the concentrations used, were not toxic to bees. In the semi-field tests, an average acaricidal efficacy of 33% and 60% was obtained, at the highest concentration used, for bergamot and lemon essential oils, respectively. During the 4 weeks of exposure to 600 mL of BEO, the average mite mortality was 28.5%. In the experimental group treated with the intermediate concentration of 1200 mL, the average mite mortality at the end of four weeks was 30.2%, while with the highest concentration of 1800 mL, it was 40.3%. During the four weeks of exposure to 600 mL of LEO, the average mite mortality was 34.1%. In the experimental group treated with the 1200 mL concentration, the average mite mortality at the end of the four weeks was 46.6%, while with the highest concentration, it was 50.7%. This study shows that the acaricidal efficacy observed in field tests differs from that in laboratory tests. Innovative formulations are needed that allow the time-controlled and gradual release of essential oil in the field. Full article

In order to describe the population dynamics of R. microplus in the southern region of the state of Paraná, Brazil, and to identify racial differences between hosts in the level of infestation by this parasite, the teleogins of approximately 70 males per year were counted every 14 days for 5 years. The herd comprised eight genetic groups, aged 12 to 24 months, in an area of 76 ha (60 ha of native fields and 16 ha of Hemarthria altíssima). The monthly averages of the counts per animal were analyzed using the GENMOD procedure, which accounts for the effects of genetic group, month, genetic group × month and cycle. Three generations of ticks of increasing infestation intensity were analyzed in December, February and May, respectively. Animals from Caracu and Canchim breeds as well as Charolais × Caracu and Aberdden Angus × Canchim cross-breeds had the lowest levels of infestation compared to Charolais and Aberdeen Angus. We conclude that by employing the aforementioned mixed breeds, in combination with a strategic control of initiating the application of acaricides in November, followed by two to three treatments every 21 days, this procedure represents the most effective method of controlling ticks in this region. Full article

Resistance to amitraz in Varroa destructor mites poses a significant challenge to global beekeeping, leading to the declining efficacy of treatments and increased colony losses. This study aims to comprehensively map, characterize, and analyze the status of amitraz efficacy and resistance in Varroa and other parasitic mites such as Tropilaelaps spp. and Acarapis woodi. A systematic review, following PRISMA 2020 guidelines, examined 74 studies, revealing substantial variability in experimental protocols, mite origins, and environmental factors, all of which impacted toxicity assessments. These findings highlight the urgent need for standardized methodologies to ensure consistency and reliability. Resistance ratios (RR) and indices (RI) showed significant geographical variation, reflecting localized resistance development. Laboratory studies highlighted inconsistencies in detecting resistance, underscoring the importance of combining bioassays, molecular diagnostics, and field efficacy tests. Understanding the genetic and physiological mechanisms driving amitraz resistance, as well as their prevalence, is vital to devising sustainable management strategies. Establishing national monitoring programs and revising testing protocols are pivotal steps toward ensuring the continued effectiveness of acaricides. These measures, combined with coordinated efforts by researchers, beekeepers, and policymakers, are essential to safeguarding global honey bee populations and supporting the long-term sustainability of apiculture. Full article

The cattle tick, Rhipicephalus microplus, is the most significant ectoparasite in the cattle industry. The application of acaricides constitutes the main control method. However, inadequate treatments have serious drawbacks, including the appearance of multi-resistant ticks. Tick vaccines offer a safe and economically sustainable alternative for controlling R. microplus. Nevertheless, the efficacy of existing vaccines has been limited by polymorphisms in target antigens among strains from different geographical regions. In this study, we characterized a putative Metalloprotease from the ADAMTSL family. We analyzed three regions to evaluate their transcriptional profiling in different R. microplus tick tissues, using two constitutive genes (β-tubulin and Elfa-1) as references. The expression levels showed that ADAMTSL-R1 was upregulated 39.37-fold (p ≤ 0.05) in salivary glands. The ADAMTSL-R2 showed the highest expression, rising 7.69-fold (p ≤ 0.05) in ovaries and up to 59.39-fold (p ≤ 0.05) in egg mass. Furthermore, this region showed the highest level of conservation among Rhipicephalus isolates. The ADAMTSL-R3 was upregulated only in the egg mass. The results of this study provide a basis for future research focused on elucidating the role of these protein variants in tick biology, including their feeding mechanisms and potential implications in pathogen transmission. Understanding these factors may aid in developing an effective tick vaccine. Full article

Ticks pose significant challenges to public and veterinary health, acting as vectors of several diseases that affect animals and humans. Traditional chemical control methods, such as pyrethroids and organophosphates, have led to increasing resistance and environmental contamination, highlighting the need and urgency for alternative strategies. This review explores contemporary approaches to tick control, emphasizing plant-derived acaricides and their integration with nanotechnology. Plant extracts, known for their acaricidal properties, disrupt several biological processes in ticks, reducing reproduction and survival rates. The advent of nanotechnology offers promising advances in increasing the efficacy of these natural extracts. Nanoparticles add properties to the systems where they act by improving the stability, bioavailability, and targeted delivery of plant-derived compounds, potentially overcoming the limitations of traditional acaricides. This synthesis of current knowledge highlights the potential of combining plant extracts with nanotechnology to develop sustainable and effective tick control solutions, addressing issues of acaricide resistance as well as environmental concerns. The review also identifies research gaps and suggests directions for future studies to optimize the application of nanotechnology in tick management. Full article

Tetranychus urticae (Acari: Tetranychidae) is a pervasive and damaging mite pest of tomato crops, leading to important economic losses globally. This study evaluated the acaricidal efficacy of spinosad, alone and in combination with Beauveria bassiana (Bb) WG-21 and Metarhizium robertsii (Mr) WG-04, in the laboratory (application to tomato leaf discs) and greenhouse (application to tomato plants), considering mortality and establishment, respectively. The combination treatments of Bb WG-21 or Mr WG-04 with spinosad achieved 100% mortality of T. urticae nymphs within 2 days on leaf discs, while individual applications of each control agent resulted in lower mortalities, ranging between 62.91 and 86.25% after 3 days. The paired treatment of Mr WG-04 + spinosad killed all exposed adults within 5 d, while that of Bb WG-21 + spinosad achieved the same results after 7 d. However, spinosad, Mr WG-04, and Bb WG-21 alone killed ≥77.08% of adults after 7 d. In the greenhouse, the combination treatment of WG-04 + spinosad deterred the presence of T. urticae (adults, immatures, and eggs) on either surface of the tomato leaves, while Bb WG-21 + spinosad suppressed the populations only on the adaxial surface. These findings indicate that combined treatments of the tested EPF + spinosad, especially Mr WG-04, on tomato plants under greenhouse conditions can provide substantially enhanced control of T. urticae life stages compared to each treatment applied alone. Full article

Varroa destructor represents one of the most significant pathogens affecting Apis mellifera. A multitude of treatment modalities exist, including those based on pharmaceutical and biotechnological principles. A few years after the first use of synthetic acaricides, Varroa destructor developed resistance to these substances, becoming a significant concern. The present review assesses the potential risk of resistance development to formic and lactic acid. This is performed by evaluating sources in the literature over the past 30 to 40 years following the PRISMA 2020 guidelines. Median annual efficacies are determined and evaluated over time. Independent of pharmaceutical form, mite populations are considered non-resistant for efficacies higher than 70%. After the assessment of outliers for lactic acid, the remaining limited data are insufficient to draw conclusions on resistance. The reported unusually low efficacy values for formic acid can be explained by inadequate evaporation rates and study settings. Notably, for both acids, the findings are limited by a low number of efficacy values, and further, more detailed and standardized studies are needed. Full article

Rhipicephalus (Boophilis) microplus (also known as southern cattle tick or Asian blue tick) is one of the most detrimental and prolific tropical cattle parasites. Currently, chemical acaricides used against these ticks have been less effective due to increased pesticide resistance stemming from overuse of these treatments. We propose a novel tick repellent to address the waning efficacy of chemical treatments for R. (B.) microplus on cattle. In the search for an alternative, seven concentrations (100%, 50%, 25%, 12.5%, 6.25%, 3.13%, and 1.57%) of babaçu (Attalea speciosa) residue bio-oil were produced by hydrothermal pyrolysis at 180 °C. The repellency of these bio-oil concentrations was assessed using a tick climbing test. Additionally, toxicity tests were performed by organic chemical analysis and polyaromatic hydrocarbon analysis. The repellency to R. (B.) microplus tick larvae was 100% for concentrations higher than 3.13% babaçu residue bio-oil concentration. However, the 1.57% concentration can be promising even with less repellent effects (though still being 93.7% effective) due to lower toxicity. This is an innovative approach for overcoming drug resistance in these ticks. Future research can test other bio-oils and pyrolysis products as tick repellents and botanical acaricides to further diversify options for better managing these parasites in Brazil and elsewhere in the tropics. Full article

Ticks are well-known vectors of pathogens, posing considerable risks to livestock health and productivity. In Cameroon, where livestock production is vital, established tick species such as Amblyomma variegatum and Hyalomma truncatum are prevalent in key cattle-rearing areas. The recent introduction of the invasive, acaricide-resistant Rhipicephalus microplus further complicates control efforts. In this study, we deliver baseline data on the composition of tick species and their shifts within agroecological zone I (AEZ I) and agroecological zone III (AEZ III) of Cameroon, providing a foundation for targeted vector control strategies to ultimately reduce the risk of pathogen transmission. From 1100 ticks collected across two Cameroonian agroecological zones, H. truncatum (39.9%), A. variegatum (31%), and R. microplus (10.64%) were the most prevalent species, along with Rhipicephalus lunulatus (4.45%), Hyalomma rufipes (1.45%), Hyalomma marginatum (1.09%), Hyalomma dromedarii (0.45%), and Rhipicephalus sanguineus (0.9%). Molecular identification using cytochrome C oxidase subunit 1 (cox1) and 16s led to the identification of five additional species, Hyalomma nitidum (0.73%), Rhipicephalus simus (3.54%), Rhipicephalus sulcatus (2.64%), Rhipicephalus praetextatus (2.1%), and Rhipicephalus pusillus (1.1%). R. microplus emerged as the most dominant Rhipicephalus spp. in AEZ I, comprising 67.5% of the total Rhipicephalus ticks. In conclusion, we demonstrate the further spread of R. microplus, which represents a major source of vector-borne diseases, affecting both humans and animals. Full article

Ticks and tick-borne diseases significantly impact animal health, public health, and economic productivity globally, particularly in areas where the wildlife–livestock interface complicates management. This review critically examines the current control strategies, focusing on chemical, biological, physical, and integrated pest management (IPM) approaches. Chemical acaricides, while effective, are increasingly challenged by resistance development and environmental concerns. Biological approaches, including natural predators and entomopathogenic fungi, and physical interventions, such as habitat modification, provide sustainable alternatives but require further optimization. IPM stands out as the most promising long-term solution, integrating multiple approaches to enhance efficacy while reducing environmental risks. Emerging innovations, such as nanotechnology-enhanced acaricides and next-generation vaccines, offer promising avenues for improved tick control. Addressing the complex challenges of tick management requires tailored strategies, interdisciplinary collaboration, and sustained research investment in both veterinary and public health contexts. Full article