Search Results (140)

Tick-borne diseases pose a significant threat to global cattle production, with species displacement between ticks compounding this issue. This narrative review synthesises the literature to examine the drivers behind the expansion of the invasive Rhipicephalus microplus and its displacement of the native Rhipicephalus decoloratus in Southern Africa. We analysed the biological, ecological, environmental, and anthropogenic factors by reviewing existing scientific studies and reports. Our findings indicate that R. microplus possesses a competitive advantage due to its shorter life cycle, higher reproductive output, and greater acaricide resistance. Furthermore, anthropogenic activities such as communal grazing practices, unregulated livestock movement, and land-use changes facilitate the spread of this parasite. Climate change and vegetation shifts also create more favourable habitats for this invasive species. The conclusion is that the displacement of R. decoloratus by R. microplus intensifies the burden of tick-borne diseases, leading to substantial economic losses. Effective mitigation requires an integrated tick management approach that combines chemical, biological, and ecological strategies, supported by improved surveillance and farmer education. Full article

Over the past 20 years, honey bee colony declines have been driven by multiple factors, notably diseases and parasites. The parasitic mite Varroa destructor, which weakens the bees’ immune systems, has been particularly harmful. While various synthetic acaricides are used, the chemicals may accumulate in the beeswax, endangering colony health and allowing Varroa populations to develop resistance to these acaricides. These problems have prompted interest in organic alternatives like thymol and oxalic acid. In this study, colony health was assessed through the proteins-to-phenolics spectral ratio in honey and beeswax, determined by fluorescence spectroscopy, as a ratiometric indicator of infection level in treated hives. Over two months, hives were treated with either oxalic acid, thymol, or remained untreated as controls. Neither treatment significantly affected the proteins-to-phenolics ratios in honey, ranging from 0.30 to 0.83, or in beeswax, ranging from 1.40 to 1.83, suggesting that the incorporation of these vital constituents remains stable despite acaricide application. While thymol demonstrates potential adverse effects on bee health, careful management of treatment concentrations is essential to ensure both the efficacy of Varroa control and the preservation of honey quality. These findings provide valuable insights for beekeepers regarding the safe application of organic acaricides. Full article

This study aimed to evaluate the efficacy of various control alternatives against Varroa destructor in Apis mellifera colonies in a semi-arid region of Mexico. One hundred and ten homogeneous colonies, with a uniform population and infestation level of V. destructor, were randomly distributed into the following 11 experimental groups (10 colonies/group): amitraz, oxalic acid in glycerin (OA-G), oxalic acid in sugar syrup (OA-SS), ethanolic extracts of Bursera penicillata, Larrea tridentata, and Lippia graveolens, powdered sugar dusting, three vehicle controls (vegetable oil, ethanol, glycerin), and one untreated control. Efficacy was determined by recording mite fall during the treatment period relative to a subsequent reference treatment. Significant differences were observed among treatments (p < 0.0001). Amitraz was the most effective (94.4%), followed by OA-G (85.1%). The OA-SS and plant extracts showed intermediate efficacy (62.1% to 73.7%), while sugar dusting showed lower values (55.8%) but still higher than the control (31.2%). These findings support the restricting of amitraz use to minimize resistance risk and suggest implementing OA-G as a high-efficacy alternative. Furthermore, ethanolic plant extracts and powdered sugar dusting combined with sticky bottom boards may serve as accessible, complementary tools within integrated pest management programs to reduce reliance on synthetic acaricides and mitigate the development of resistance. Full article

Background: The control of fleas and ticks in companion animals is a persistent challenge with animal welfare and public health implications. The increasing resistance to antiparasitic treatments, coupled with concerns over the environmental impact and non-target effects of synthetic acaricides, has driven interest in sustainable alternatives. Essential oils (EOs) have emerged as potential candidates due to their complex chemistry and modes of action. Methods: This review critically analyzes the scientific literature on essential oils for ectoparasite control in companion animals. Specifically, it examines their chemical composition, multi-target mechanisms of action, laboratory and field efficacy, role in resistance mitigation, and integration into IPM strategies. Results: Several EOs, particularly those rich in phenolic compounds (thymol, carvacrol, eugenol, and cinnamaldehyde), demonstrate promising in vitro insecticidal and acaricidal activity. Their multi-target mechanisms, affecting neuronal, respiratory, and cuticular functions, not only provide efficacy but also represent a significant barrier to rapid resistance development. However, their translation to reliable field performance is hampered by high volatility, formulation instability, and innate variability. Conclusions: EOs represent a valuable source of bioactive compounds for reducing reliance on conventional acaricides and can play a key role within IPM strategies. To realize their full potential in mitigating resistance, focused advancements are needed in standardized testing, formulation science to enhance stability and residual activity, and rigorous field studies to confirm safety and efficacy. Full article

Carvone-rich essential oils (EOs), and carvone specifically, exhibit a broad spectrum of protective effects against major agricultural threats. They display strong antifungal and moderate antibacterial effects, effectively inhibiting numerous phytopathogenic fungi. EOs exhibit significant insecticidal, acaricidal, and repellent activity against various insects and mites, and some EOs are highly effective against agricultural nematodes, suppressing mobility and egg hatching. Crucially, the EOs demonstrate a strong capacity to suppress the germination and initial growth of different weed species, highlighting their viability as natural herbicides. This review analyzes the chemical composition, biological effects, and potential agricultural applications of carvone and carvone-rich essential oils, primarily sourced from Mentha spicata (Lamiaceae), Carum carvi (Apiaceae), and Anethum graveolens (Apiaceae). The biological activity of these EOs is significantly influenced by their specific composition, which varies among plant species and chemotypes. While EOs’ inherent volatility limits direct field application, this challenge is being successfully addressed by innovative formulation technologies, such as nanoemulsification and encapsulation, which enhance stability, bioavailability, and targeted delivery. In conclusion, carvone-rich EOs offer effective, environmentally low-risk agents for the integrated management of pathogens, pests, and weeds in sustainable agriculture. They help reduce reliance on synthetic chemicals and minimize the potential for resistance development. Full article

The increasing resistance of agricultural pests to conventional pesticides necessitates the development of alternative biological control strategies. This study evaluated the acaricidal potential of two Photorhabdus luminescens strains (0805-P2R and the newly isolated 2103-RUVI) against the spider mite Tetranychus truncatus. Culture conditions were optimized using a Taguchi L9(3⁴) design to maximize growth, protease activity, and acaricidal efficacy. The optimized medium for strain 2103-RUVI achieved 90% mortality against T. truncatus at 72 h, compared to 83% for strain 0805-P2R under equivalent conditions. Genomic analysis identified putative phosphoporin PhoE genes exclusively in 2103-RUVI, which may contribute to its enhanced virulence, although this association remains correlative and requires functional validation. Histopathological observations confirmed severe tissue disruption in treated mites. Comparative analysis demonstrated complex, strain-specific relationships among bacterial growth, enzyme activity, and acaricidal effects. These results highlight the potential of the P. luminescens strain 2103-RUVI as an effective biocontrol agent, providing insights for its application in sustainable integrated pest management programs. Full article

The two-spotted spider mite, Tetranychus urticae Koch, is a major agricultural pest whose control is increasingly constrained by resistance to synthetic acaricides. This study evaluated the long-term field efficacy of three commercial entomopathogenic fungal (EPF) biopesticides—Velifer^® (Beauveria bassiana), Metab^® (B. bassiana + Metarhizium anisopliae), and Botanigard^® (B. bassiana)—against larval and protonymph stages of T. urticae on two host plants, Italian cypress (Cupressus sempervirens) and sweet orange (Citrus sinensis). Two foliar applications were conducted during the 2023 growing season (25 May and 25 July), and mite populations were monitored for 140 days after the final application. A randomized complete block design was used, and efficacy was calculated using the Henderson–Tilton formula. All EPF treatments significantly reduced mite populations compared with the untreated control throughout the monitoring period. Velifer consistently achieved the highest suppression of larval populations, particularly on C. sinensis, with efficacy comparable to the chemical standard. Botanigard showed more gradual but sustained population reduction over time, whereas Metab exhibited lower but stable efficacy in all cases. Treatment performance was strongly influenced by host plant species and mite developmental stage, with larvae consistently more susceptible than protonymphs. On C. sinensis, Velifer achieved the highest larval suppression (84.6%), comparable to the chemical standard abamectin, while Botanigard and Velifer were most effective on C. sempervirens. Survival analysis confirmed isolate- and host-dependent differences in hazard effects over time. These results demonstrate that EPF-based products can provide sustained, long-term suppression of T. urticae under field conditions, supporting their integration into integrated pest management programs. Full article

Tick-borne diseases (TBDs) pose a significant threat to livestock productivity and rural livelihoods in South Africa, particularly among resource-poor communal farmers. This narrative review synthesises findings from case studies on communal farmers’ knowledge, attitudes, and practices (KAPs) toward TBDs and their control. The analysis reveals that while many farmers can identify TBDs and their symptoms, significant gaps exist in understanding acaricide resistance and effective tick management. Socioeconomic factors, including age, gender, education, and access to veterinary services, strongly influence knowledge and practices. Indigenous ethnoveterinary practices are commonly used alongside conventional methods, although their efficacy remains understudied. The review emphasises the importance of integrated pest management, participatory approaches, and targeted awareness campaigns. A One Health framework is recommended to enhance surveillance, collaboration, and sustainable TBD control. Empowering farmers through training and inclusive communication strategies is crucial for mitigating the impacts of TBDs on communal farming systems. Full article

Ticks and tick-borne diseases (TBDs) impose a heavy burden on South African livestock systems, particularly in resource-limited communal areas. Conventional acaricides are effective but face rising challenges of resistance, high costs, and concerns for environmental and human health. As a result, there is growing interest in plant-based tick control rooted in ethnoveterinary knowledge. This review examines the landscape of South African ethnoveterinary practices for tick control and assesses the supporting evidence of bioactivity and pathways for translating these remedies into safe, registered products. A narrative review method was applied, drawing on the literature (2000–2025) from databases and local repositories, with emphasis on South African studies documenting plant use against ticks. Communities in Limpopo, Eastern Cape, KwaZulu-Natal, and other provinces utilise a diverse range of botanicals (e.g., Lippia javanica, Tetradenia riparia, Clausena anisata, Tagetes minuta, Melia azedarach, Eucalyptus spp., Cymbopogon spp.) to repel or kill ticks, often through topical applications, fumigation, or livestock housing treatments. Laboratory assays have confirmed acaricidal or repellent activity in many of the cited taxa. For example, Lippia javanica and Tagetes minuta oils demonstrate strong tick repellency, while extracts of Tetradenia riparia and Calpurnia aurea exhibit greater than 70% mortality in vitro. Field studies are fewer but promising: a community-led trial with L. javanica leaf spray achieved substantial tick reduction (albeit slightly less efficacious than synthetic amitraz). Key gaps include standardisation of plant preparations, safety evaluations (toxicity and residue studies), and alignment with regulatory requirements. Recent regulatory updates in South Africa (Act 36 of 1947) underscore the need for quality, safety, and efficacy data but also create avenues for low-risk botanical remedies. Ethnoveterinary plants offer a culturally appropriate and eco-friendly complement to conventional acaricides. Bridging the gap to practical use will require multidisciplinary efforts: validating efficacy in well-designed field trials, ensuring consistency in preparation, assessing safety margins, and navigating registration pathways for plant-based stock remedies. With supportive policy and community engagement, South Africa could pioneer farmer-ready botanical acaricides that mitigate resistance, reduce costs, and advance One Health objectives. Full article

Rhipicephalus microplus, also known as the Asiatic blue tick, is an invasive ectoparasite of significant economic and animal health importance in South Africa. This review synthesises evidence on its ongoing range expansion, which is displacing the native R. decoloratus, driven by factors including climate suitability, livestock movement, and communal grazing practices. The tick’s success is compounded by widespread, multi-class acaricide resistance, which has been documented across all major chemical classes. Molecular diagnostics are crucial for accurate surveillance, and population genetics reveal significant gene flow facilitated by livestock movement. Projections indicate that climate change will further expand the tick’s suitable habitat. Current reliance on chemical control is unsustainable. We conclude that an integrated parasite management (IPM) approach combining strategic acaricide rotation, targeted selective treatments, pasture management, and strict biosecurity is critical for sustainable control. Key recommendations include establishing standardised, national resistance monitoring, validating molecular markers for resistance prediction, and developing farmer-facing decision-support tools. This synthesis provides a framework for research and policy to mitigate the impact of R. microplus at the wildlife-livestock interface in South Africa. Full article

The growing resistance of Tetranychus urticae to chemical pesticides highlights the need for alternative solutions for its sustainable control. To develop botanical acaricides and reduce the usage of chemical pesticides, this study assessed the acaricidal activity of AB extract and its combinations with four commercial insecticides: imidacloprid (IMI), acetamiprid (ACE), thiamethoxam (TMX), and bifenthrin (BF). Results showed that the AB extract suppressed detoxification enzymes and downregulated their corresponding genes in T. urticae. Bioassays identified hyoscyamine and genistein as key bioactive compounds. Field trials revealed that treatments with AB + IMI, AB + TMX, and AB + BF significantly enhanced the corrected efficacy against T. urticae compared with AB treatment, with the highest corrected efficacy observed for AB + BF. Notably, the AB + BF treatment did not influence the stability of the natural enemy community, as indicated by the characteristic indices of the natural enemy community, which suggests that the integration of AB extract with BF may represent a sustainable pest management strategy. Therefore, the AB extract represents an environmentally benign alternative to chemical pesticides for the sustainable control of T. urticae. Full article

The tick Rhipicephalus sanguineus is the most prevalent ectoparasite in dogs, causing discomfort to the animals and acting as a vector for several pathogens, including the bacterium Ehrlichia canis and the protozoa Babesia canis, Babesia gibsoni, and Hepatozoon canis. Control of this parasite is traditionally carried out with synthetic chemical acaricides. However, due to the increasing number of cases of resistance, phytotherapy has been increasingly investigated as a promising alternative. In this study, the larvicidal activity of the crude ethanolic extract and essential oil obtained from the inflorescences of Achyrocline satureioides was evaluated, whose constituents were identified through phytochemical analyses and gas chromatography. The analyses revealed that the extract is rich in flavonoids, tannins, and saponins, while the essential oil is composed mainly of terpenes. In contact tests with impregnated paper, the extract at 100 mg/mL showed a mortality rate of 32.2% in R. sanguineus larvae with LC₅₀ calculated at 249.62 mg/mL, while the essential oil, at the same concentration, resulted in 56.55% mortality, and the LC₅₀ and LC₉₀ were 119.73 mg/mL and 185.53 mg/mL, respectively. These results indicate that the essential oil of A. satureioides has significant larvicidal activity and has potential for use as an alternative, alone or in combination with other extracts or synthetic acaricides. Full article

The two-spotted spider mite, Tetranychus urticae, is a global pest with increasing resistance to conventional acaricides, prompting the search for sustainable alternatives. Essential oils (EOs) are promising botanical biocides due to ecological safety and multitarget action. We evaluated lethal and sublethal effects of EOs from Alpinia zerumbet and Mesosphaerum suaveolens against T. urticae. Oils were obtained by hydrodistillation and characterized by GC–MS (major constituents: A. zerumbet—1,8-cineole 14.05%, sabinene 12.6%; M. suaveolens—β-sabinene (predominant), spathulenol 12.28%, 1,8-cineole 11.01%). In adult bioassays, M. suaveolens was more toxic (LC₅₀ = 4.24 µL mL⁻¹), whereas A. zerumbet showed LC₅₀ = 8.74 and LC₉₀ = 46.24 µL mL⁻¹. In ovicidal assays at LC₉₀, egg viability declined to 2% with A. zerumbet versus 57% with M. suaveolens. Repellency at sublethal concentrations (LC₂₀–LC₃₀) was high for both oils (≥75%) and exceeded 90% for M. suaveolens. Both oils suppressed population growth (instantaneous rate r_i reduced from 0.5848 in the control to 0.4746–0.5155 under treatments). PCA confirmed lethal concentration and repellency as the main discriminators among treatments. These data demonstrate the multitarget potential of A. zerumbet and M. suaveolens EOs as botanical acaricides for sustainable management of T. urticae. Full article

Ticks transmit diseases and harm animals worldwide, and their control primarily relies on pesticides. Resistance to these pesticides has developed consistently over centuries. Arginine Kinase (AK, EC 2.7.3.3) is a conserved, ancestral enzyme that provides reserve energy in emergency situations and a viable target for novel antiparasitic drugs. Our aim was to evaluate six carbamoyl carboxylic acid analogues (CCAs) as potential lead compounds by investigating their interaction with the active site of Rhipicephalus sanguineus AK (RsAK) using a structural modeling approach. The binding was characterized using fluorescence quenching (Stern–Volmer analysis) and molecular dynamics simulations. The simulations, performed with GROMACS using the CHARMM 26 force field over 100 ns, provided atomic-level insight into the ligand–protein interactions and stability. CCA4 exhibited the lowest dissociation constant (K_D~13·10⁻⁶ M) among the analogues, which we attribute to its end moieties (carboxylate and a pyridine on the ends). Purely aromatic ends (CCA1) or those with dual carboxylates (CCA6) showed lower affinity, suggesting that electrostatic complementarity and steric fit are processes involved in the binding. Despite requiring optimization, the CCA scaffold represents a novel strategy for tick control. These compounds provide a foundation for developing synergistic agents to enhance the efficacy of sustainable acaricides. Full article

The two-spotted spider mite (Tetranychus urticae Koch) (Acari: Tetranychidae) is one of the most widespread and destructive phytophagous mite species, occurring across all climatic zones worldwide. Currently, the control of spider mites in crop protection relies primarily on chemical acaricides. However, the selection of resistant populations to their active ingredients is reducing their efficacy. The aim of the present study was to assess the susceptibility of T. urticae to a native isolate of entomopathogenic nematodes, Steinernema feltiae Filipjev ZWO21, under laboratory conditions. The experiment was conducted using Petri dishes, each containing 22–28 adult T. urticae. Infective juveniles (IJs) of the nematodes were then applied at a dose of 8000 IJs per dish (±300 IJs per mite). Petri dishes with mites treated with nematodes were placed in a Sanyo incubation chamber at 25 °C and 60% relative humidity. After three days, dead mites were collected from the Petri dishes and dissected, and mortality was subsequently determined. The present study confirmed that the S. feltiae ZWO21 isolate exhibited considerable potential for the biological control of T. urticae, causing 37.5–83.3% (mean 57.0%) mortality in this pest species. Although this result indicates a moderate efficacy when nematodes are applied alone, it also underscores the relevance of further research into their integration with other control strategies, including acaricides, within integrated pest management (IPM) programmes. Full article