Search Results (100)

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

The castor bean tick (Ixodes ricinus) is a widespread European ectoparasite and vector of multiple diseases that can impair cattle health and productivity. This study evaluated whether a single application of a gel microencapsulated acaricide (α-cypermethrin and permethrin) reduces I. ricinus infestation in dairy cows and affects milk yield. Twenty cows were allocated to treated and control groups; treated animals received one spray at the start of the grazing season, and tick counts were recorded daily for 196 days with monthly milk-yield measurements. Two activity peaks were observed (June and September–October) with reduced abundance in July–August; all control cows were parasitised, with daily counts of 1–18 ticks (median = 2). During the first month after treatment, the acaricide reduced tick numbers by around 80% versus controls (p < 0.001); efficacy declined over the ensuing months, and differences were negligible after about five months. No adverse effect on milk yield was detected (p = 0.38), and seasonal variation (p < 0.0001) and lactation stage (p < 0.001) were the primary determinants of production. Primiparous and young cows, as well as cows in mid-to-late lactation, tended to show higher levels of tick infestation. A single application of the gel microencapsulated product provided a significant reduction in tick burden during the first month after treatment in grazing dairy cows, without a negative impact on milk production, supporting its use in endemic areas. Full article

The two-spotted spider mite, Tetranychus urticae Koch, is a major arthropod pest that causes substantial economic losses in strawberry and other crops worldwide. Its management often relies on intensive acaricide applications, which may negatively affect human health, the environment, and beneficial organisms. Biological control using predatory mites has been widely adopted under greenhouse conditions, and its success is influenced by several factors, particularly temperature, T. urticae population density, and predator release methods. During the 2023–2024 season, this study evaluated the effects of ambient greenhouse temperature on the population dynamics of T. urticae and on the efficacy of two phytoseiid predators, Phytoseiulus persimilis (Athias-Henriot) and Amblyseius swirskii (Athias-Henriot). The predators were released individually and in combination on strawberry plants. The efficacy of single and combined releases was assessed under three temperature ranges: 25–27 °C, 28–30 °C, and 30–32 °C. The results showed that the mean number of motile T. urticae per plant increased from 21.7 to 95.66, while the mean number per leaf increased from 2.33 to 6.05 during the experimental period. The mean greenhouse temperature ranged from 23.83 °C to 31.88 °C. Temperature was strongly and positively correlated with T. urticae population density, with higher temperatures generally accelerating development and population growth. Both predator species, whether released individually or in combination, significantly reduced T. urticae populations compared with untreated control plants. Amblyseius swirskii demonstrated greater efficacy than P. persimilis at temperatures above 28 °C. However, the combined release consistently achieved the highest level of mite suppression across all temperature ranges. Significantly greater population reduction was observed at approximately 25–26 °C compared with single-species releases, while maximum effectiveness occurred at temperatures above 28 °C. These findings indicate that the combined use of P. persimilis and A. swirskii represents an effective biological control strategy for managing T. urticae in greenhouse-grown strawberries, particularly under elevated and fluctuating temperature conditions. Full article

Rhipicephalus microplus infestations are a major concern for cattle production in neotropical regions. Anti-tick vaccines represent a sustainable alternative to chemical acaricides; however, improving vaccine efficacy remains challenging. This study evaluated the protective efficacy of polypeptide-based formulations of pBm86 and pSubolesin administered as co-immunization or as a cocktail in naturally infested cattle. Twelve calves were assigned to three groups: G1: 100 μg pBm86 + 50 μg pSubolesin co-immunized; G2: same formulation in cocktail; and G3: control. The cocktail significantly reduced adult female tick numbers, oviposition, and larvae hatching (p < 0.05), achieving a vaccine efficacy of 75%. In contrast, co-immunization achieved 50% efficacy. Vaccinated cattle developed significantly increased antigen-specific IgG levels against Subolesin than Bm86. IgG antibodies recognized native tick proteins by Western blot, and their efficacy was confirmed in vitro using blood-feeding assays. These results indicate that the cocktail formulation showed improved efficacy compared with co-immunization in this study, possibly by affecting complementary biological processes in ticks. Finally, this study supports the development of multi-antigen, polypeptide-based vaccines as a promising and sustainable approach for the control of R. microplus under natural field conditions. 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

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

Recently, ornamental plants in urban and unmanaged landscapes were found to be infected with several plant viruses transmitted by Brevipalpus mites. The main purpose of this research was to identify suitable tools for managing Brevipalpus yothersi in these environments by evaluating the efficacy, persistence, and rainfastness of selected biorational pesticides, as well as their compatibility with the predatory mite Amblyseius largoensis. We found that horticultural oils (i.e., petroleum distillates with varying levels of refinement, marketed as mineral or paraffinic oils) and Beauveria bassiana (Strain GHA) suppressed all developmental stages of B. yothersi at levels comparable to spirodiclofen, a commonly used acaricide for controlling B. yothersi. The paraffinic oil provided the best overall performance across the rainfastness, residuality, and greenhouse evaluations. This food-grade horticultural oil is exempt from residue tolerances and could be readily adopted for B. yothersi control in urban landscapes. Paraffinic oil had adverse effects on predatory mites. However, predator populations recovered after paraffinic oil application, and the combined treatment of paraffinic oil + A. largoensis ultimately provided better control than either the predators or the oil alone. When properly applied, horticultural oils provide a practical option for controlling populations of viruliferous Brevipalpus mites in urban and unmanaged landscapes. 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

The predatory mite Neoseiulus womersleyi is a key natural enemy in Integrated Pest Management (IPM), but its efficacy is threatened by non-target effects of acaricides like pyridaben. This study evaluated the transgenerational sublethal effects of pyridaben (LC₃₀ and LC₅₀) on N. womersleyi and explored the role of vitellogenin (Vg) genes. Using two-sex life table analysis, we found that exposure reduced longevity, fecundity, and oviposition period in F₀ females, while prolonging immature development and suppressing population growth parameters (r, λ) in F₁. Two Vg genes (NwVg1 and NwVg2) were cloned and characterized; their expression was significantly downregulated by pyridaben. RNAi-mediated silencing of NwVg1 or NwVg2 recapitulated the pyridaben-induced reproductive impairments, confirming their functional role. Our results demonstrate that pyridaben imposes multigenerational costs and that its reproductive toxicity is mediated, at least in part, through the suppression of Vg synthesis. 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

Varroa destructor remains a major threat to honey bee (Apis mellifera) health, requiring effective and sustainable control strategies. In this study, a formic acid-based product (Formic Pro™) was tested for its varroacidal efficacy and effects on hygienic behavior of honey bee colonies. Sixty hives were assigned to three groups: Formic Pro group (n = 30), Positive control treated with amitraz (n = 15), and untreated Negative control (n = 15). Efficacy was assessed by daily mite drop counts, while hygienic behavior was evaluated before and after treatment using the “pin-killed” brood method. The Formic Pro group achieved a mite mortality rate of 88.37% ± 0.23, while amitraz as a control exerted 94.30% ± 0.95 efficacy. The treatment was well tolerated, with no queen losses, minimal and transient brood effects, followed by brief bearding on the first day of trial. Hygienic behavior significantly increased in the Formic Pro group (PCC from 96.69% to 99.01%, p < 0.001), while it declined in the Negative control and remained unchanged in the Positive control group. These results demonstrate that the tested formic acid-based product provides high acaricidal efficacy which is tolerated well in colonies and that it stimulates a key behavioral defense mechanism through hygienic behavior, providing benefits both for Varroa control and colony resilience. 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

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

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