Acute toxicity effects of pesticides on predatory snout mites (Trombidiformes: Bdellidae).

Predatory mites biologically control a range of arthropod crop pests and are often central to agricultural IPM strategies globally. Conflict between chemical and biological pest control has prompted increasing interest in selective pesticides with fewer off-target impacts on beneficial invertebrates, including predatory mites. However, the range of predatory mite species included in standardized pesticide toxicity assessments does not match the diversity of naturally occurring species contributing to biocontrol, with most testing carried out on species from the family Phytoseiidae (Mesostigmata). Here, we aim to bridge this knowledge gap by investigating the impacts of 22 agricultural pesticides on the predatory snout mite, Odontoscirus lapidaria (Kramer) (Trombidiformes: Bdellidae). Using internationally standardized testing methodologies, we identified several active ingredients with minimal impact on O. lapidaria mortality, including Bacillus thuringiensis, nuclear polyhedrosis virus, flonicamid, afidopyropen, chlorantraniliprole, and cyantraniliprole, which may therefore be good candidates for IPM strategies utilizing both chemical and biological control. Comparison of our findings with previous studies on Phytoseiid mites reveals important differences in responses to a number of chemicals between predatory mite families, including the miticides diafenthiuron and abamectin, highlighting the risk of making family-level generalizations from acute toxicity assessments. We also tested the impacts of several pesticides on a second Bdellidae species (Trombidiformes: Bdellidae) and found differences in the response to chlorpyrifos compared with O. lapidaria, further highlighting the taxon-specific nature of nontarget toxicity effects.

Ecotoxicity evaluation using the avoidance response of the oribatid mite Oppia nitens (Acari: Oribatida) in bioplastics, microplastics, and contaminated Superfund field sites.

Bioplastics are considered sustainable alternatives to conventional microplastics which are recognized as a threat to terrestrial ecosystems. However, little is known about the potential ecotoxicological effects of bioplastics on soil fauna and ecosystems. The present study assessed the toxicity of microplastics [Polystyrene (PS), Polyethylene (PE)] and bioplastics [Polyvinyl alcohol (PVA), Sodium polyacrylate (NaPa) on a key soil fauna Oppia nitens, a soil oribatid mite, and investigated the ecological relevance of O. nitens avoidance response as a valuable tool for the risk assessment of contaminated soils such as the Superfund sites. Findings showed that the mites' net response indicated avoidance behavior such that in most cases as concentrations of micro- and bioplastics increased, so did the avoidance responses. The avoidance EC50 endpoints showed PS < PE < PVA < NaPa, indicating higher deleterious effects of microplastics. High toxicity of PS in soils to O. nitens at EC50 of 165 (±25) mg/kg compared to bioplastics and other known contaminants poses an enormous threat to soil. For bioplastics in this study, there were no significant avoidances at concentrations up to 16,200 mg/kg compared to PS and PE which showed avoidance responses at 300 and 9000 mg/kg respectively, implying that bioplastics might be relatively safer to soil mites compared to conventional microplastics. Also, results indicated that long-term heavy metal pollution such as in contaminated Superfund sites decreased microbial biomass; a useful bioindicator of soil pollution. Furthermore, O. nitens avoidance of heavy metals contaminated sites demonstrated the ecological relevance of avoidance response test when assessing the habitat integrity of contaminated soil. The present study further supports the inclusion of the oribatid mite, O. nitens in the ecological risk assessment of contaminants in soil.

Acute toxicity effects of pesticides on beneficial organisms - Dispelling myths for a more sustainable use of chemicals in agricultural environments.

Agricultural practitioners, researchers and policymakers are increasingly advocating for integrated pest management (IPM) to reduce pesticide use while preserving crop productivity and profitability. Using selective pesticides, putatively designed to act on pests while minimising impacts on off-target organisms, is one such option - yet evidence of whether these chemicals control pests without adversely affecting natural enemies and other beneficial species (henceforth beneficials) remains scarce. At present, the selection of pesticides compatible with IPM often considers a single (or a limited number of) widely distributed beneficial species, without considering undesired effects on co-occurring beneficials. In this study, we conducted standardised laboratory bioassays to assess the acute toxicity effects of 20 chemicals on 15 beneficial species at multiple exposure timepoints, with the specific aims to: (1) identify common and diverging patterns in acute toxicity responses of tested beneficials; (2) determine if the effect of pesticides on beetles, wasps and mites is consistent across species within these groups; and (3) assess the impact of mortality assessment timepoints on International Organisation for Biological Control (IOBC) toxicity classifications. Our work demonstrates that in most cases, chemical toxicities cannot be generalised across a range of beneficial insects and mites providing biological control, a finding that was found even when comparing impacts among closely related species of beetles, wasps and mites. Additionally, we show that toxicity impacts increase with exposure length, pointing to limitations of IOBC protocols. This work challenges the notion that chemical toxicities can be adequately tested on a limited number of 'representative' species; instead, it highlights the need for careful consideration and testing on a range of regionally and seasonally relevant beneficial species.

Comparative sensitivity of Neoseiulus cucumeris and its prey Tetranychus cinnabarinus, after exposed to nineteen pesticides.

The toxicity tests of nineteen commonly used pesticides were carried out to compare the sensitivity differences between predatory mite Neoseiulus cucumeris and its prey Tetranychus cinnabarinus by a "leaf spray method" in laboratory microcosms. For two avermectins, emamectin benzoate and abamectin, exhibited high bioactivity against T. cinnabarinusf with LR50 values of 0.04 and 0.05 g a.i./ha, respectively, but these two insecticides showed the opposite toxic effects to N. cucumeris. These two agents showed strong selectivity for the two test species with Selective Toxicity Rate (STR) values of 950 and 620, respectively. However, for five neonicotinoids, the LR50s of dinotefuran, thiamethoxam, imidacloprid, and acetamiprid were all greater than the recommended rates in the field except for clothianidin, and they showed no obvious toxicity difference to the two species with STR values ranging from 0.58 to 2.00. For two organophosphates, malathion is more toxic to N. cucumeris than T. cinnabarinus, however, dimethoate showed a higher toxic effect on T. cinnabarinus. In addition, the toxicity of four pyrethroids, bifenthrin, deltamethrin, cyhalothrin and gamma-cyhalothrin to N. cucumeris was higher than that of T. cinnabarinus, except for alpha-cypermethrin. For five acaricides, spirodiclofen, spirotetramat and pyridaben had no obvious selectivity to the two organisms, while diafenthiuron and chlorfenapyr were found to be highly toxic to T. cinnabarinus than N. cucumeris with STR values of 14.2 and 68.5, respectively. Thus, some pesticides above-mentioned like emamectin benzoate, abamectin, diafenthiuron and chlorfenapyr exhibited potential to be used in the management programs of T. cinnabarinus, especially in organically based production systems where there are fewer chemical control measures available, which need to combine with natural enemies to achieve the best control effect.

The sensitivity of Demodex canis (Acari: Demodicidae) to the essential oil of Melaleuca alternifolia - an in vitro study.

The essential oil of the Melaleuca alternifolia (Maiden & Betche) (tea tree oil) has been effective in previous studies, in the treatment of infestation by Demodex mites in humans. The present study aimed at evaluating the in vitro acaricidal effect of this herbal medicine on Demodex canis. For the parasitological examination, samples were collected from a dog's skin and examined using optical microscopy. Only samples with intact mites and with evident movement of chelicerae and tarsi were selected. Twenty-one samples were tested with the oil, in seven different concentrations: 100%; 50%; 25%; 12.5%; 6.25%; 5.0% and 3.13%. Three samples were tested with the positive control amitraz, and three with the negative control neutral shampoo. The interval between the time the solution was added and the moment the movement of the last mite ceased defined the survival time in the sample. By comparing the times at different concentrations and controls, the results showed that the higher the concentration of the oil, the more quickly its lethal effect occurred, and that the survival times in the controls were longer than in the different concentrations of melaleuca oil.

In vitro acaricidal activity of essential oil and alcoholic extract of Trachyspermum ammi against Dermanyssus gallinae.

This study aimed to assess in vitro acaricidal activity of essential oil (EO) and alcoholic extracts (AE) of Ajowan against D. gallinae. Using contact and spraying bioassays, different doses of EO and AE were tested. Cypermethrin and thymol (positive controls), and ethanol and distilled water (negative controls) were also tested. The results indicated that effects were method and dose dependent. Statistical analysis showed a highly significant difference for contact and spraying bioassays and various doses of EO and AE (p < 0.0001) as, the spraying method was more effective than the contact method for acaricidal activity at 24 h post treatment (PT). In this method, Cypermethrin, EO and thymol caused over 90 % mite mortality at 50 µgcm-2, while AE caused this rate at 150 µgcm-2. In the contact bioassay, all tests produced low mortality rates except for Cypermethrin. Thymol was the main constituent of EO (Area = 42.26 %) and AE (Area = 45.8 %). Results of the present study indicated that Ajowan had a satisfactory acaricidal effect against D. gallinae in vitro. It was also found that the spraying method could be used to control the D. gallinae as the most appropriate method.

Biological activities and phytochemical screening of leaf extracts from Zanthoxylum caribaeum L. (Rutaceae) / Atividades biológicas e prospecção fitoquímica de extratos vegetais das folhas de Zanthoxylum caribaeum L. (Rutaceae)

The Brazilian flora is known for its vast biodiversity; however, many species have been still little studied regarding to their chemical composition and biological potential. Thus, this study aimed to determine the antimicrobial, antioxidant and acaricidal activity of the extracts of leaves of Zanthoxylum caribaeum L. In addition, phytochemical screening of these extracts was carried out to determine the main classes of secondary metabolites present in Z. caribaeum. Using the Z. caribaeum leaves, aqueous and organic extracts were obtained using the following solvents (ethanol, methanol, hexane, acetone, dichloromethane and ethyl acetate). The antimicrobial activity of extracts was determined by broth microdilution method, and to detect antioxidant activity the method of capturing the free radical 2,2-diphenyl-1-picryl hydrazyl (DPPH) was used. The acaricidal activity of the extracts was tested on Dermanyssus gallinae (De Geer) (Acari: Dermanissidae). Ethanolic and methanolic extracts presented antimicrobial activity for most of the bacterial strains tested, as well as for yeast Candida albicans. The ethanolic extract presented high free radical sequestration potential (71.2%) and antioxidant capacity (the lowest IC50 value - 24.39 µg mL-1). The crude extracts obtained with methanol and acetone were the most promising. In general, phytochemical screening indicated the presence of steroids, flavanones, flavones, flavonols, saponins, tannins, triterpenoids and xanthones.

A flora brasileira é conhecida pela sua vasta biodiversidade, no entanto, muitas espécies ainda são pouco estudadas quanto à composição química e ao potencial biológico. Assim, esse trabalho teve como objetivo determinar a atividade antimicrobiana, antioxidante e acaricida dos extratos vegetais das folhas de Zanthoxylum caribaeum L. Adicionalmente, foi realizada triagem fotoquímica desses extratos para determinar as principais classes de metabólitos secundários presentes em Z. caribaeum. Empregando-se as folhas de Z. caribaeum foram obtidos o extrato aquoso e orgânicos, utilizando os seguintes solventes (etanol, metanol, hexano, acetona, diclorometano e acetato de etila). A atividade antimicrobiana dos extratos foi determinada pelo método de microdiluição em caldo, e para detecção da atividade antioxidante foi empregado o método de captura do radical livre 2,2-difenil-1-picril hidrazil (DPPH). A atividade acaricida dos extratos foi avaliada frente a Dermanyssus gallinae (De Geer) (Acari: Dermanissidae). Os extratos brutos etanólico e metanólico apresentaram atividade antimicrobiana para a maioria das cepas bacterianas testadas, e também para a levedura Candida albicans. O extrato etanólico apresentou elevado potencial de sequestro de radicais livres (71,2%) e o menor valor de IC50 (24,39µg mL-1), revelando, portanto, sua capacidade antioxidante. No que se refere à atividade acaricida, os extratos obtidos com metanol e acetona foram os mais promissores. De modo geral, a triagem fitoquímica indicou a presença de esteroides, flavanonas, flavonas, flavonóis, saponinas, taninos, triterpenóides e xantonas.

The efficacy and safety of permethrin 2.5% with tea tree oil gel on rosacea treatment: A double-blind, controlled clinical trial.

BACKGROUND: Rosacea is a chronic skin condition that typically affects the face and it results in redness and inflammation. The main risk factors of this disease are Demodex folliculorum, living in the pilosebaceous units. AIMS: To evaluate the efficacy and safty of permethrin 2.5% in combination with tea tree oil (TTO) topical gel versus placebo on Demodex density (Dd) and clinical manifestation using standard skin surface biopsy (SSSB) in rosacea patients. PATIENT/METHODS: In this double-blind, randomized clinical trial, 47 papulopustular rosacea patients were enrolled, with 35 patients finishing the 12 weeks of treatment. Each patient used permethrin 2.5% with TTO on one side of the face and a placebo on the other, twice daily for 12 weeks. SSSB, photography and clinical rosacea scores according to National Rosacea Society, as well as adverse drug reaction (ADRs) were reported at the baseline, 2nd, 5th, 8th, and 12th weeks. RESULTS: A total of 47 patients were enrolled with papulopustular rosacea, and 35 patients finished the study. The effects of permethrin 2.5% with TTO gel on mite density were significant at week 5, 8, 12 (P value = .001). Clinical features and global assessments showed papules, pustules and nontransient erythema had improvement in drug group after 12 weeks (P values <.05). The improvement of burning and stinging and dry appearance was greater than the placebo gel (P value <.05). Itching in placebo group was significantly more than other group (P value = .002). CONCLUSION: Administration of permethrin 2.5% with TTO gel demonstrated good efficacy and safety in rosacea. This topical gel inhibited the inflammatory effects of rosacea and reduced Demodex mite.

The sensitivity of Demodex canis (Acari: Demodicidae) to the essential oil of Melaleuca alternifolia - an in vitro study / A sensibilidade do Demodex canis (Acari: Demodicidae) ao óleo essencial de Melaleuca alternifolia - um estudo in vitro

Abstract The essential oil of the Melaleuca alternifolia (Maiden & Betche) (tea tree oil) has been effective in previous studies, in the treatment of infestation by Demodex mites in humans. The present study aimed at evaluating the in vitro acaricidal effect of this herbal medicine on Demodex canis. For the parasitological examination, samples were collected from a dog's skin and examined using optical microscopy. Only samples with intact mites and with evident movement of chelicerae and tarsi were selected. Twenty-one samples were tested with the oil, in seven different concentrations: 100%; 50%; 25%; 12.5%; 6.25%; 5.0% and 3.13%. Three samples were tested with the positive control amitraz, and three with the negative control neutral shampoo. The interval between the time the solution was added and the moment the movement of the last mite ceased defined the survival time in the sample. By comparing the times at different concentrations and controls, the results showed that the higher the concentration of the oil, the more quickly its lethal effect occurred, and that the survival times in the controls were longer than in the different concentrations of melaleuca oil.

Resumo O óleo essencial de Melaleuca alternifolia (Maiden & Betche) (óleo da árvore do chá) foi eficaz em estudos anteriores, no tratamento da infestação por ácaros Demodex em humanos. O presente estudo teve por objetivo avaliar o tempo do efeito acaricida, in vitro, desse fitoterápico sobre Demodex canis. Para o exame parasitológico, amostras foram coletadas da pele de um cão e examinadas por microscopia óptica. Apenas amostras com ácaros íntegros e com evidente movimentação de quelíceras e tarsos foram selecionadas. Vinte e uma amostras foram direcionadas para teste com o óleo, em sete concentrações diferentes: 100%; 50%; 25%; 12,5%; 6,25%; 5,0% e 3,13%. Três amostras foram testadas com o controle positivo, amitraz, e três com o controle negativo, xampu neutro. O intervalo entre o momento em que a solução foi adicionada e o instante em que cessou o movimento do último ácaro definiu o tempo de sobrevivência na amostra. Os tempos nas diferentes concentrações e nos controles foram comparados. Quanto mais alta a concentração do óleo, mais rapidamente ocorreu seu efeito letal. Os tempos de sobrevivência nos controles foram maiores que nas diferentes concentrações do óleo de melaleuca.

Pyrethroid resistance in the pest mite, Halotydeus destructor: Dominance patterns and a new method for resistance screening.

An L1024F substitution in the para gene, which encodes a subunit of the voltage-gated sodium channel, has been implicated in pyrethroid resistance in a mite pest, Halotydeus destructor, which attacks rape and other grain crops. A high-resolution melt (HRM) genotyping assay was developed for testing the relative pyrethroid susceptibility of different para genotypes and for high-throughput field screening of resistant alleles. The L1024F mutation was found to be incompletely recessive in phenotypic laboratory bioassays with the pyrethroid pesticide, bifenthrin. While the resistance ratio of heterozygotes (RS) to susceptible homozygotes (SS) was <6 in 24 h bioassays, the resistant homozygotes (RR) (with a resistance ratio > 200,000) survived the recommended field rate of bifenthrin (100 mgL-1). HRM genotyping of mites from field populations across Australia indicated the presence of resistant alleles in Western Australia and South Australia, but not in Victoria and New South Wales. The assay developed will be useful for routine screening of pyrethroid resistance, and the dominance relationships established here point to useful resistance management strategies involving the maintenance of reservoirs of susceptible mites to dilute resistant homozygotes in a population.

Sublethal effect of Abamectin in the functional response of the predator Phytoseiulus persimilis (Athias-Henriot) on Tetranychus urticae (Koch) (Acari: Phytoseiidae, Tetranychidae) / Efeito subletal da Abamectina na resposta funcional do predador Phytoseiulus persimilis (Athias-Henriot) em Tetranychus urticae (Koch) (Acari: Phytoseiidae, Tetranychidae)

Abstract The biological control used for the control of Tetranychus urticae (Koch) is the predator mite Phytoseiulus persimilis (Athias-Henriot). It is important to the know the effects of acaricides on the biological behavior the Abamectin on the functional response of P. persimilis. The functional response of the predator was of type II exposed to concentration of Abamectin, the functional response parameters: successful attack rate (a'), handling time (Th), search efficiency and the maximum predation theory (T/Th) were affected by the acaricide. The predator spends more time in persecute, dominate, consume and prepair it self to the next searching comparing with the proof subject an the predation ability was affected.

Resumo O controle biológico utilizado para o controle de Tetranychus urticae (Koch) é o acaro predador Phytoseiulus persimilis (Athias-Henriot). É importante conhecer os efeitos dos acaricidas sobre o comportamento biológico do predador. Foi avaliado o efeito tóxico de a Abamectina na resposta funcional de P. persimilis. A resposta funcional do predador foi tipo II exposta a concentrações subletais de Abacmetina, os parâmetros da resposta funcional: taxa de ataque (a'), tempo de manipulação (Th), a eficiência na procura e predação teórica máxima (T/Th) foram afetados pelo acaricida. O predador passa mais tempo na procura, dominar, consumir e se preparar para a próxima procura em comparação com a testemunha e sua capacidade de predação foi afetada.

Tropical oribatid mites in soil toxicity testing: Optimization of test protocol and the effect of two model chemicals (cadmium and dimethoate) on Muliercula inexpectata.

The oribatid mite, Oppia nitens, has gained recognition in recent laboratory ecotoxicological tests, however, the species global distribution is limited to temperate regions and not ecologically relevant for tropical soils. The present study reports the first laboratory study aimed at assessing the ecotoxicity of contaminants with the tropical oribatid mite, Muliercula inexpectata. To develop the protocols, synchronized adult specimens of M. inexpectata were tested in a natural soil collected at the Teaching and Research Farm of the Obafemi Awolowo University, Ile-Ife, Nigeria. An optimization test was done using different soil quantities (5, 20, 40 g), durations (14, 21, 28 d) and temperature regimes (20, 22, 24, 26, and 28 °C). The results show M. inexpectata peak juvenile production at 28 d and temperatures of 24-26 °C in 20 g of soil. Test conditions were further optimized to assess the effects of cadmium and dimethoate on adult lethality and reproduction of M. inexpectata using 20 g of soil, with an exposure temperature of 26 °C for a duration of 28 d. The LC50 (survival) and EC50 (reproduction) values of cadmium for M. inexpectata were 46.55 (26.26-82.52) mg/kg and 15.61 (13.65-20.63) mg/kg, respectively. The LC50 and EC50 values of dimethoate for M. inexpectata were 7.57 (5.40-10.60) and 4.42 (0-7.16) mg/kg, respectively. Compared to other mite species, they are either more or less sensitive depending on the chemicals considered. The results of the present study demonstrate that M. inexpectata is a promising candidate for routine and ecologically-relevant ecotoxicological assessments in tropical regions.

The response of three species of phytoseiid mite (Acari: Phytoseiidae) to synthetic pyrethroid pesticides in the laboratory and the field.

The Kanzawa spider mite, Tetranychus kanzawai Kishida, is a major pest in tea fields [Camellia sinensis (L.) O. Kuntze] in Japan. However, recently, there have been some instances where acaricides are no longer applied as a result of the low occurrence of T. kanzawai in tea fields in Japan. In the period of 2015-2017, surveys of predatory mites in the study tea field detected Amblyseius eharai Amitai and Swirski, Phytoseiulus persimilis Athias-Henriot, Euseius sojaensis (Ehara), Amblyseius obtuserellus Wainstein and Begljarov, and Typhlodromus vulgaris Ehara in tea fields, but not Neoseiulus womersleyi (Schicha), indicating that a major change in the composition of the phytoseiid mite population had occurred. In laboratory studies, we confirmed the ability to avoid synthetic pyrethroid insecticides of the major beneficial mites in tea fields, A. eharai and P. persimilis, but not of E. sojaensis, a predatory mite whose population declined heavily after pesticide application. Attempts are made in this study to associate the decrease in T. kanzawai frequency in Japan with changes in pesticide used, method of spraying, and composition of the phytoseiid mite population. By continuing the method of pesticide spraying ('partial surface'), which leaves refugia in the leaf layer with sub-lethal dosages of pesticide, phytoseiid mites are aided to evade pesticides, resulting in maintenance of the composition of the phytoseiid mite populations in terms of diversity and abundance. Maintaining the diversity and abundance of Phytoseiidae may have contributed to the stabilization of the T. kanzawai population at low densities in Japanese tea fields.

Comparing the in vitro effects of MGO™ Manuka honey and tea tree oil on ocular Demodex viability.

PURPOSE: To compare the in vitro antiparasitic effects of MGO™ Manuka honey and tea tree oil against ocular Demodex. METHODS: Fifty-two viable Demodex mites were acquired from the epilated eyelashes of 9 participants with blepharitis and symptomatic dry eye. Viable mites were randomised to one of five treatment groups: cyclodextrin-complexed and uncomplexed Manuka Honey, 100% and 50% tea tree oil, and no treatment. Following treatment application, mite viability was assessed for 240 min, based on limb and body movement and/or the development of a crenated/translucent appearance. Kaplan-Meier survival analysis was then performed. RESULTS: The log-rank test demonstrated a significant treatment effect on the survival distribution of Demodex mites (p < 0.001). Bonferroni-corrected post-hoc pairwise analysis showed that all treatments except for uncomplexed honey effected lower survival probabilities than the untreated group (all p < 0.001). Among the four treatments, survival probabilities were lowest with 100% tea tree oil (all p < 0.001), and highest with uncomplexed honey (all p ≤ 0.001). No difference was observed between complexed honey and 50% tea tree oil (p = 0.81). CONCLUSIONS: The in vitro efficacy of cyclodextrin-complexed Manuka honey was comparable with 50% tea tree oil, an established treatment for ocular Demodex. The findings support future clinical trials investigating the therapeutic effects of complexed honey in demodectic blepharitis patients.

Acaricidal and insecticidal effects of essential oils against ectoparasites of veterinary importance / Efectos acaricidas e insecticidas de los aceites esenciales contra los ectoparásitos de importancia veterinaria

Ectoparasitism in animals has become an issue of great concern that needs to be resolved to prevent huge economic losses occurring to livestock industry all over the world. Synthetic adrugs have been playing a major role in controlling ectoparasites, but their frequent and irrational use has resulted in drug resistance to routinely used chemicals and their residual effects on food and environment. Therefore, this approach of using chemical acaricides and insecticides is losing its popularity and effectiveness in controlling ectoparasites. So, the development of alternative approaches in ectoparasite management is currently required. Among alternative protocols, plants and their essential oils have played remarkable role in controlling different ectoparasites (ticks, flies, mites, lice) of veterinary importance. Essential oils have been proved to be cheaper, more effective and safer therapeautic agents against different ectoparasites of livestock importance.

En los animales el ectoparasitismo se ha convertido en un tema de gran preocupación que debe resolverse para evitar que se produzcan grandes pérdidas económicas para la industria ganadera en todo el mundo. Los aditivos sintéticos han desempeñado un papel importante en el control de los ectoparásitos, pero su uso frecuente e irracional ha dado como resultado la resistencia a los fármacos utilizados habitualmente y efectos residuales sobre los alimentos y el medio ambiente. Por lo tanto, el enfoque basado en el uso de acaricidas e insecticidas químicos está perdiendo popularidad y efectividad en el control de los ectoparásitos. Por lo tanto, actualmente se requiere el desarrollo de enfoques alternativos en el manejo de ectoparásitos. Entre los protocolos alternativos, las plantas y sus aceites esenciales han jugado un papel notable en el control de diferentes ectoparásitos (garrapatas, moscas, ácaros, piojos) de importancia veterinaria. Se ha demostrado que los aceites esenciales son agentes terapéuticos más baratos, más efectivos y más seguros contra diferentes ectoparásitos de importancia ganadera.

Evaluation of the Efficacy of Tea Tree Oil On the Density of Demodex Mites (Acari: Demodicidae) and Ocular Symptoms In Patients With Demodectic Blepharitis.

The objective of this study was to examine the efficacy of 7.5% tea tree oil (TTO) eyelash shampoo on the density of Demodex (Acari: Demodicidae) and ocular symptoms in patients with demodectic blepharitis. A total of 135 patients diagnosed with demodectic blepharitis, following clinical inspection and parasitological examinations, were included in the study. Patients were treated with eyelash shampoo, with or without TTO. Full Demodex reduction was attained in 36% of the patients who used eyelash shampoo with TTO, and the average Demodex count was reduced from 6.33/eyelash to zero ( P < 0.001). In contrast, the average Demodex count in patients who did not achieve full reduction (64%) was reduced from 12.46/eyelash to 4.15/eyelash ( P < 0.001). Full reduction was observed in 11.7% of patients who used TTO-free eyelash shampoo, and average Demodex count reduced from 2.00/eyelash to zero ( P = 0.017). The average Demodex count was reduced from 11.98/eyelash to 7.91/eyelash in patients (88.3%) who did not achieve full reduction ( P = 0.024). Additionally, ocular symptom scores (which are generated based on subjective experiences of itching, burning, the feeling of a foreign body in the eye, eye redness, and cylindrical dandruff) were reduced significantly ( P < 0.001) in patients who used the eyelash shampoo with TTO. The symptom scores remained almost the same in patients who used TTO-free eyelash shampoo ( P > 0.05). In conclusion, it was determined that eyelash shampoo with TTO is 3 times more effective at achieving full Demodex reduction, significantly reducing the Demodex count, and relieving ocular symptoms in patients where full reduction cannot be attained, without adverse side effects.

Repellency, toxicity, and anti-oviposition of essential oil of Gardenia jasminoides and its four major chemical components against whiteflies and mites.

We examined the repellent, insecticidal, and anti-oviposition activities of the ethanol-extracted essential oil of Gardenia jasminoides against Bemisia tabaci and Tetranychus urticae adult and nymph stages under laboratory and greenhouse conditions. We used GC-MS to identify the main chemicals in the essential oil and selected four compounds, squalene, ethyl linoleate, n-hexadecanoic acid and 9-12-octadecadienoic, to evaluate their activity on whiteflies and mites. In the laboratory experiments, the essential oil of G. jasminoides showed maximum effects in fumigation against whitefly adults (81.48%) and contact toxicity against whitefly nymphs (46.44%), adult mites (49.81%), and mite nymphs (66.46%). In the greenhouse experiments, squalene showed maximum repellency against whitefly adults at 24 (89.59%) and 48 h (84.76%), whitefly nymphal toxicity at 24 (80.08%) and 48 h (77.28%), and mite toxicity at 24 (78.74%) and 48 h (73.86%). The essential oil showed maximum anti-oviposition activity against whiteflies at 24 (63.58%) and 48 h (59.56%) and toxicity to mite nymphs at 24 (82.45%) and 48 h (57.14%) in the bioassay. The essential oil had LC50 values of 2396.457, 2844.958, 56,990.975 and 21,468.619 against whitefly adults, whitefly nymphs, mite adults and mite nymphs, respectively. G. jasminoides and its major chemicals may effectively control the whiteflies and mites.

SUCCESSFUL TREATMENT OF GENERALIZED DEMODICOSIS IN RED-HANDED TAMARINS ( SAGUINUS MIDAS) USING A SINGLE ADMINISTRATION OF ORAL FLURALANER.

Two adult sibling red-handed tamarins ( Saguinus midas) presented with weight loss and multifocal skin masses. A skin biopsy revealed pyogranulomatous dermatitis with intrafollicular Demodex sp. mites. Subsequent skin scrapes confirmed the presence of live mites within lesions. Initial treatment with topical and oral ivermectin was unsuccessful, and lesions continued to progress. A single dose of fluralaner (Bravecto®, Merck Animal Health, Kenilworth, New Jersey, 07033, USA; 28.125 mg po) was administered to each animal approximately 5 mo after initial presentation. Lesions resolved over the next 3 mo, and all follow-up skin scrapes were negative for both animals. No adverse effects were noted. A single oral administration of fluralaner at 30-35 mg/kg appears adequate and safe for the treatment of generalized demodicosis in red-handed tamarins.

A field trial in Thailand of the efficacy of oral fluralaner for the treatment of dogs with generalized demodicosis.

BACKGROUND: Generalized demodicosis in dogs can be challenging to manage, especially in adult-onset cases. HYPOTHESIS/OBJECTIVES: This study evaluated the efficacy of oral fluralaner at the dose of 25-50 mg/kg for the treatment of canine generalized demodicosis. ANIMALS: Client-owned dogs from Bangkok, Thailand, diagnosed with generalized demodicosis according to published criteria. METHODS: Deep skin scrapings were performed at three to five affected areas to evaluate numbers of mites. Repeat examinations were performed monthly until parasitological cure; dogs were then followed up for two to 12 months. Parasitological cure was defined as two negative skin scrapings achieved one month apart. RESULTS: One hundred and fifteen dogs were included in the study, 73 with adult-onset demodicosis and 42 with juvenile-onset demodicosis. Twenty one dogs were lost to follow-up and 27 had one negative skin scraping but did not return. Sixty seven dogs (21 with juvenile-onset and 46 with adult-onset disease) reached parasitological cure, which occurred after two, three and four months in 63%, 85% and 100% (respectively) of dogs with adult-onset demodicosis, cumulatively, and after two and three months in 81% and 100% of dogs with juvenile-onset demodicosis. Underlying causes associated with adult-onset demodicosis included atopic dermatitis, neoplasia, metabolic diseases and idiopathy. No adverse effects of fluralaner were observed in any of the dogs. CONCLUSION: Fluralaner given at the label dose for flea and tick prevention is effective for the treatment of canine generalized demodicosis.

Chitosan nanoparticles functionalized with ß-cyclodextrin: a promising carrier for botanical pesticides.

Carvacrol and linalool are natural compounds extracted from plants and are known for their insecticidal and repellent activities, respectively. However, their low aqueous solubility, high photosensitivity, and high volatility restrict their application in the control of agricultural pests. The encapsulation of volatile compounds can be an effective way of overcoming such problems. Inclusion complexes between beta-cyclodextrin (ß-CD) and carvacrol (CVC) or linalool (LNL) were investigated. Inclusion complexes were prepared by the kneading method. Both complexes presented 1:1 host:guest stoichiometry and the highest affinity constants were observed at 20 °C for both molecules. The nanoparticles containing carvacrol and linalool had mean diameters of 175.2 and 245.8 nm, respectively and high encapsulation efficiencies (<90%) were achieved for both compounds. Biological assays with mites (Tetranychus urticae) showed that the nanoparticles possessed repellency, acaricidal, and oviposition activities against this organism. Nanoencapsulated carvacrol and linalool were significantly more effective in terms of acaricidal and oviposition activities, while the unencapsulated compounds showed better repellency activity. The nanoformulations prepared in this study are good candidates for the sustainable and effective use of botanical compounds in agriculture, contributing to the reduction of environmental contamination, as well as promoting the effective control of pests in agriculture.