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1.
Parasit Vectors ; 17(1): 307, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39014392

RESUMO

BACKGROUND: Pyrethroid chemicals are one of the main acaricides used against ticks. Resistance to these chemicals has been reported to be associated with mutations in the voltage-gated sodium channel (VGSC) gene of the Rhipicephalus microplus. This study investigates R. microplus resistance to pyrethroids in Guangxi region of China, marking one of the first research efforts in this area. The findings are intended to provide vital baseline for the effective implementation of localized tick control strategies. METHODS: From March to July 2021, 447 R. microplus tick samples were collected from five prefecture-level cities in Guangxi. Allele-specific polymerase chain reaction (AS-PCR) was used to amplify segments C190A and G215T of the domain II S4-5 linker and T2134A of domain III S6 in the VGSC, to detect nucleotide mutations associated with resistance to pyrethroid acaricides. Subsequent analyses were conducted to ascertain the prevalence, types of mutations, and genotypic distributions within the sampled populations. RESULTS: Mutations within VGSC gene were identified across all five studied populations of R. microplus, although the mutation rates remained generally low. Specifically, the most prevalent mutation was C190A, observed in 4.9% of the samples (22/447), followed by G215T at 4.0% (18/447), and T2134A at 1.3% (6/447). The distribution of mutations across three critical sites of the VGSC gene revealed four distinct mutation types: C190A, G215T, C190A + G215T, and T2134A. Notably, the single mutation C190A had the highest mutation frequency, accounting for 4.3%, and the C190A + G215T combination had the lowest, at only 0.7%. The analysis further identified seven genotypic combinations, with the wild-type combination C/C + G/G + T/T predominating at a frequency of 90.4%. Subsequently, the C/A + G/G + T/T combination was observed at a frequency of 4.3%, whereas the C/C + T/T + T/T combination exhibited the lowest frequency (0.2%). Additionally, no instances of simultaneous mutations at all three sites were detected. Geographical differences in mutation types were apparent. Both samples from Hechi to Chongzuo cities exhibited the same three mutation types; however, C190A was the most prevalent in Hechi, while G215T dominated in Chongzuo. In contrast, samples from Beihai to Guilin each exhibited only one mutation type: G215T occurred in 12.5% (4/32) of Beihai samples, and C190A in 7.5% (4/53) of Guilin samples. CONCLUSIONS: These findings underscore the relatively low frequency of VGSC gene mutations in R. microplus associated with pyrethroid resistance in the Guangxi, China. Moreover, the variation in mutation types and genotypic distributions across different locales highlights the need for regionalized strategies in monitoring and managing pyrethroid resistance in tick populations. This molecular surveillance is crucial for informing targeted control measures and mitigating the risk of widespread resistance emergence.


Assuntos
Acaricidas , Mutação , Piretrinas , Rhipicephalus , Canais de Sódio Disparados por Voltagem , Animais , Rhipicephalus/genética , Rhipicephalus/efeitos dos fármacos , China/epidemiologia , Canais de Sódio Disparados por Voltagem/genética , Piretrinas/farmacologia , Acaricidas/farmacologia , Genótipo , Resistência a Medicamentos/genética , Alelos , Feminino , Infestações por Carrapato/veterinária , Infestações por Carrapato/parasitologia , Infestações por Carrapato/epidemiologia
2.
Parasites Hosts Dis ; 62(2): 217-225, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38835262

RESUMO

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


Assuntos
Acaricidas , Ixodidae , Óleos Voláteis , Animais , Óleos Voláteis/farmacologia , Ixodidae/efeitos dos fármacos , Acaricidas/farmacologia , Ninfa/efeitos dos fármacos , Repelentes de Insetos/farmacologia , Óleos de Plantas/farmacologia , Feminino , Eucalyptus/química , Óleo de Cravo/farmacologia , Lavandula , Haemaphysalis longicornis
3.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 36(2): 179-183, 2024 May 06.
Artigo em Chinês | MEDLINE | ID: mdl-38857963

RESUMO

OBJECTIVE: To investigate the activity of Acorus tatarinowii extracts against dust mites, and to isolate and characterize active ingredient of A. tatarinowii extracts. METHODS: The essential oil components were extracted from A. tatarinowii rhizome powder by rotary evaporation with methanol as solvents, followed by petroleum ether extraction and rotary evaporation. The essential oil was mixed with Tween-80 at a ratio of 1:1 and diluted into concentrations of 1.000 00%, 0.500 00%, 0.250 00%, 0.125 00%, 0.062 50% and 0.031 25%, while diluted Tween-80 served as controls. A. tatarinowii essential oil at each concentration (200 µL) was transferred evenly to filter papers containing 100 adult mites, with each test repeated in triplicate, and controls were assigned for each concentration. Following treatment at 25 °C and 75% relative humidity for 24 h, the mean corrected mortality of mites was calculated. The essential oil components were separated by silica gel column chromatography, and the essential oil was prepared in the positive column of medium pressure; and then, each component was collected. Silica gel column chromatography was run with the mobile phase that consisted of petroleum ether solution containing 10% ethyl acetate and pure ethyl acetate, detection wavelength of 254 nm, positive silica gel column as the chromatography column, and room temperature as the column temperature. Each component of the purified A. tatarinowii essential oil was diluted into 1.000 00% for acaricidal tests. The components with less than 100% acaricidal activity were discarded, and the remaining components were diluted into 50% of the previous-round tests for subsequent acaricidal tests. The components with acaricidal activity were subjected to high-performance liquid chromatography, liquid chromatography-mass spectrometry and pulsed-Fourier transform nuclear magnetic resonance spectroscopy. The structure of active monomer compounds was determined by standard spectral library retrieval and literature review. RESULTS: A. tatarinowii essential oil at concentrations of 1.000 00%, 0.500 00%, 0.250 00% and 0.125 00% killed all dust mites, and the corrected mortality was all 100%. Exposure to A. tatarinowii extracts at an effective concentration of 0.062 50% for 24 hours resulted in 94.33% mortality of dust mites. Six components (A to F) were separated using gel column chromatography, and components D and E both showed a 100% acaricidal activity against dust mites at a concentration of 0.50000%. In addition, Component D was identified as isoeugenol methyl ether, and Component E as ß-asarinol. CONCLUSIONS: The extract of A. tatarinowii essential oil has acaricidal activity, and the isoeugenol methyl ether shows a remarkable acaricidal activity against dust mites.


Assuntos
Acorus , Óleos Voláteis , Extratos Vegetais , Pyroglyphidae , Animais , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Acorus/química , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Acaricidas/farmacologia , Acaricidas/química
4.
Ticks Tick Borne Dis ; 15(5): 102362, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38852539

RESUMO

A promising alternative approach to conventional vector and rodent control practices is the use of a bait containing a rodenticide and acaricide in controlling vectors and pathogen reservoirs concurrently. In the United States, Lyme disease continues to be the most prevalent vector-borne disease with approximately 500,000 Lyme disease cases estimated each year. Previous research has demonstrated the usefulness of a low dose fipronil bait in controlling Ixodes scapularis larvae feeding on white-footed mice. However, considering white-footed mice can be an unwanted species because of their association with tick-borne disease and hantaviruses, a combination rodent and tick bait (RTB) might provide a useful alternative to encourage additional community participation in integrated tick management (ITM) efforts. The purpose of this research was to evaluate the use of RTB (0.025 % warfarin, 0.005 % fipronil) in controlling white-footed mice and I. scapularis larvae. Studies were designed in part based on Environmental Protection Agency (EPA) guidelines. A laboratory choice test was conducted to evaluate the use of RTB in controlling white-footed mice over 15-day exposure when they were exposed to an alternative diet. Mice were observed every day for mortality and signs of warfarin toxicity. A simulated field test was conducted to evaluate the use of RTB, presented in the presence of an alternative diet, in controlling I. scapularis parasitizing white-footed mice over 4-day exposure. Mice were fitted with capsules and manually infested with I. scapularis larvae. The inside of each capsule was observed to evaluate tick attachment. Replete larvae detaching from each mouse were collected. Blood was collected from all treatment group mice via cardiac puncture to determine the fipronil sulfone concentration in plasma for each animal. Results indicated that RTB would be adequately consumed in the presence of an alternative diet under laboratory and simulated field conditions. Treatment with RTB resulted in 100 % mortality of white-footed mice during 15-day exposure and prevented 100 % larvae from feeding to repletion during 4-day exposure. All mice succumbing to RTB showed signs of warfarin toxicity. All mice parasitized with ticks that were exposed to RTB had fipronil sulfone detectable in plasma, with even the lowest concentration detected (8.1 parts per billion) controlling 100 % parasitizing I. scapularis larvae. The results suggest that RTB could be a useful means of rodent and tick control for use in ITM programs.


Assuntos
Ixodes , Doença de Lyme , Peromyscus , Controle de Ácaros e Carrapatos , Animais , Ixodes/microbiologia , Ixodes/fisiologia , Peromyscus/parasitologia , Doença de Lyme/prevenção & controle , Doença de Lyme/transmissão , Controle de Ácaros e Carrapatos/métodos , Infestações por Carrapato/veterinária , Infestações por Carrapato/prevenção & controle , Larva/microbiologia , Rodenticidas/farmacologia , Acaricidas/farmacologia , Pirazóis/farmacologia , Feminino , Vetores Aracnídeos/microbiologia
5.
Exp Appl Acarol ; 93(1): 211-227, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38864992

RESUMO

Acaricides used against Tetranychus urticae Koch, 1836 (Acari: Tetranychidae) in cotton fields cause control failure over time. To determine the resistance status of T. urticae populations to tebufenpyrad and bifenazate, different populations collected from Aydin (AYD), Adana (ADA), Sanliurfa (SAN), and Diyarbakir (DIY) provinces of Türkiye, between 2019 and 2020, were subjected to diagnostic dose bioassays. Firstly, the spider mites were eliminated with a discriminating dose. Afterwards, LC50 and LC90 of the remaining populations were determined and the ten highest resistant populations were selected. The highest phenotypic resistance to bifenazate was observed in AYD4 and DIY2 (LC50 57.14 mg L- 1 with 85.01-fold and LC50 30.15 mg L- 1with 44.86-fold, respectively), while the lowest phenotypic resistance was found in SAN6 (LC50 1.5 mg L- 1; 2.28-fold). Considering the phenotypic resistance to tebufenpyrad, the highest resistance was found in AYD4 population (LC50 96.81 mg L- 1; 12.92-fold), while the lowest - in DIY28 population (LC50 21.23 mg L- 1; 2.83-fold). In pharmacokinetic studies, the ADA16 population was compared with the sensitive German Susceptible Strain population and it was determined that carboxylesterase activity was statistically higher (1.46 ± 0.04 nmol/min/mg protein enzyme activation 2.70-fold). The highest activation of glutathione S-transferase was detected in ADA16 (1.49 ± 0.01 nmol/min/mg protein; 2.32-fold). No mutations were found in PSST (METI 1), the point mutation site for tebufenpyrad, and Cytb (METI 3), the point mutation site for bifenazate. In terms of phenotypic resistance, bifenazate was found to be moderately resistant in two populations (85.01 and 44.86-fold), while tebufenpyrad was moderately resistant in one population (12.92-fold). This study showed that both acaricides are still effective against T. urticae populations.


Assuntos
Acaricidas , Gossypium , Tetranychidae , Animais , Tetranychidae/efeitos dos fármacos , Tetranychidae/enzimologia , Acaricidas/farmacologia , Inativação Metabólica , Resistência a Medicamentos , Proteínas de Artrópodes/metabolismo , Proteínas de Artrópodes/genética
6.
Sci Rep ; 14(1): 13584, 2024 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-38866908

RESUMO

A novel, turnkey, field-based workflow was developed and validated using Rhipicephalus microplus DNA as a template to detect the presence of the voltage-gated sodium channel kdr mutation. The field-based compatible workflow comprises manual sample homogenization for DNA extraction, PCR amplification of the targets in a closed tube, and end-point detection of the PCR products. An R. microplus species-specific assay was also included to confirm species identity and ensure the validity of the kdr mutation assay. The assays were sensitive and specific to the targets, and the workflow resulted in a turnaround time of approximately 1 h at a low cost. The novel combination of PCR with closed-tube and end-point fluorescent detection allows for easy conversion of existing conventional lab-based PCR assays into field-based detection assays. The incorporation of custom-designed 3D-printed components in the workflow provides easy adaptability and modification of the components for diverse nucleic acid detection workflows.


Assuntos
Reação em Cadeia da Polimerase , Rhipicephalus , Animais , Rhipicephalus/genética , Reação em Cadeia da Polimerase/métodos , Acaricidas/farmacologia , Técnicas de Genotipagem/métodos , Resistência a Medicamentos/genética , Mutação , Genótipo , Canais de Sódio Disparados por Voltagem/genética
7.
Pestic Biochem Physiol ; 202: 105952, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38879306

RESUMO

The citrus red mite, Panonychus citri, is one of the most notorious and devastating citrus pests around the world that has developed resistance to multiple chemical acaricides. In previous research, we found that spirodiclofen-resistant is related to overexpression of P450, CCE, and ABC transporter genes in P. citri. However, the regulatory mechanisms of these detoxification genes are still elusive. This study identified all hormone receptor 96 genes of P. citri. 8 PcHR96 genes contained highly conserved domains. The expression profiles showed that PcHR96h was significantly upregulated in spirodiclofen resistant strain and after exposure to spirodiclofen. RNA interference of PcHR96h decreased expression of detoxification genes and increased spirodiclofen susceptibility in P. citri. Furthermore, molecular docking, heterologous expression, and drug affinity responsive target stability demonstrated that PcHR96h can interact with spirodiclofen in vitro. Our research results indicate that PcHR96h plays an important role in regulating spirodiclofen susceptibility and provides theoretical support for the resistance management of P. citri.


Assuntos
Compostos de Espiro , Animais , Compostos de Espiro/farmacologia , Compostos de Espiro/metabolismo , Acaricidas/farmacologia , Propionatos/farmacologia , Propionatos/metabolismo , Tetranychidae/efeitos dos fármacos , Tetranychidae/genética , Tetranychidae/metabolismo , Simulação de Acoplamento Molecular , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/metabolismo , Resistência a Medicamentos/genética , 4-Butirolactona/análogos & derivados
8.
J Agric Food Chem ; 72(27): 15276-15283, 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38943575

RESUMO

Using nicofluprole as the lead compound, we designed and synthesized a series of new phenylpyrazole analogues through substituting the methyl group on the nitrogen atom of the amide with an acyl group. Bioassay results showed that compounds A12-A17 with a 1-cyanocyclopropimide group exhibited outstanding insecticidal activity. The LC50 values for compounds A12-A17 against Tetranychus cinnabarinus ranged from 0.58 to 0.91 mg/L. Compound A15 showed an LC50 value of 0.29 and 3.10 mg/L against Plutella xylostella and Myzus persicae, respectively. Molecular docking indicated the potential binding interactions of compound A15 with a gamma-aminobutyric acid receptor. Additionally, density functional theory calculations implied that the 1-cyanocyclopropimide structure might be essential for its biological activity. Phenylpyrazole derivatives, containing a 1-cyanocyclopropimide fragment, have the potential for further development as potential insecticides.


Assuntos
Acaricidas , Desenho de Fármacos , Inseticidas , Simulação de Acoplamento Molecular , Pirazóis , Animais , Pirazóis/química , Pirazóis/farmacologia , Pirazóis/síntese química , Acaricidas/química , Acaricidas/farmacologia , Acaricidas/síntese química , Inseticidas/química , Inseticidas/farmacologia , Inseticidas/síntese química , Relação Estrutura-Atividade , Imidas/química , Imidas/farmacologia , Imidas/síntese química , Afídeos/efeitos dos fármacos , Mariposas/efeitos dos fármacos , Tetranychidae/efeitos dos fármacos , Estrutura Molecular
9.
Rev Bras Parasitol Vet ; 33(2): e001423, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38922203

RESUMO

Ticks are parasitic arthropods that cause significant economic losses to livestock production worldwide. Although Rhipicephalus (Boophilus) microplus, the cattle tick, occurs throughout the Brazilian territory, there is no official program to control this tick, which is the vector of tick fever pathogens. We address the situation of R. (B.) microplus resistance to synthetic acaricides in Brazil, including cattle tick management; the status of tick resistance per Brazilian state; the history of resistance occurrence of different acaricides; multiple resistance occurrence; and the main strategies for integrated tick management. Tick control in Brazil is characterized by management errors. Local laboratories affiliated with federal and state research institutions and universities employ the Adult Immersion Test as a primary diagnostic method to assess acaricide resistance to topically applied drugs. Only three states (Acre, Amapá, and Amazonas) have no reports on resistant populations. Misinformation on tick control strategies, misuse of available products for tick control, no adoption of Integrated Parasite Management (IPM) practices, low technical support to producers, and the high-speed emergence of acaricide-resistant tick populations are the main problems. We also propose a list of needs and priorities for cattle tick control regarding communication, research, and policies.


Assuntos
Acaricidas , Rhipicephalus , Controle de Ácaros e Carrapatos , Animais , Brasil , Bovinos , Infestações por Carrapato/prevenção & controle , Infestações por Carrapato/veterinária , Doenças dos Bovinos/prevenção & controle , Doenças dos Bovinos/parasitologia , Previsões , Resistência a Medicamentos
10.
Parasitol Res ; 123(6): 232, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38847882

RESUMO

This work evaluated if strategic control based on no more than three or four annual treatments is useful to control Rhipicephalus microplus infestations on cattle when it is applied to intensive rotational grazing and silvopastoral systems with high stocking rates in subtropical areas. In the intensive rotational grazing system, three annual treatments with chemical acaricides were applied on cattle in two different schemes: between spring and early summer and from late winter and late spring. Strategic control based on three treatments with chemical acaricides from late winter to late spring plus an additional fourth treatment in summer was tested in the silvopastoral system. In the intensive rotational grazing systems, the control schemes allow to reach a significant reduction in the tick load on cattle considering a time interval from spring to autumn. However, the efficacy levels were not high enough in some specific moments, namely, the tick counts of summer and autumn (there were not significant differences between treated and control groups). The scheme evaluated in the silvopastoral grazing system yielded better results than those tested for the intensive rotational system, because significant differences in tick load between treated and control groups were observed in all post-treatment counts and when the analysis was performed for the whole study period. However, values of efficacy in the count-by-count comparison were disparate, ranging from 64.1 to 99.7. Although the efficacy values obtained in the silvopastoral system were better than those of the rotational grazing systems, the total tick load on treated cattle in autumn was not low enough (mean abundance values 25.14 and 38.14). Ticks were more evenly distributed among hosts in late summer and autumn than in spring or early summer, where few hosts carry most of the ticks. Some management strategies as intensive rotational systems or silvopastoral structures can lead to a more efficient forage use, but they imply greater tick challenge than in extensive grazing systems. In these situations, the schemes of strategic control bases on three or four annual treatments should be complemented with additional tactical treatments in late summer or autumn.


Assuntos
Doenças dos Bovinos , Rhipicephalus , Estações do Ano , Controle de Ácaros e Carrapatos , Infestações por Carrapato , Animais , Bovinos , Rhipicephalus/fisiologia , Infestações por Carrapato/veterinária , Infestações por Carrapato/prevenção & controle , Infestações por Carrapato/parasitologia , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/prevenção & controle , Controle de Ácaros e Carrapatos/métodos , Acaricidas , Criação de Animais Domésticos/métodos
11.
Sci Rep ; 14(1): 13537, 2024 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-38866918

RESUMO

The development of interventions targeting reservoirs of Borrelia burgdorferi sensu stricto with acaricide to reduce the density of infected ticks faces numerous challenges imposed by ecological and operational limits. In this study, the pharmacokinetics, efficacy and toxicology of fluralaner were investigated in Mus musculus and Peromyscus leucopus mice, the main reservoir of B. burgdorferi in North America. Fluralaner showed rapid distribution and elimination, leading to fast plasma concentration (Cp) depletion in the first hours after administration followed by a slow elimination rate for several weeks, resulting in a long terminal half-life. Efficacy fell below 100% while Cp (± standard deviation) decreased from 196 ± 54 to 119 ± 62 ng/mL. These experimental results were then used in simulations of fluralaner treatment for a duration equivalent to the active period of Ixodes scapularis larvae and nymphs. Simulations showed that doses as low as 10 mg/kg have the potential to protect P. leucopus against infestation for a full I. scapularis active season if administered at least once every 7 days. This study shows that investigating the pharmacology of candidate acaricides in combination with pharmacokinetic simulations can provide important information to support the development of effective interventions targeting ecological reservoirs of Lyme disease. It therefore represents a critical step that may help surpass limits inherent to the development of these interventions.


Assuntos
Acaricidas , Borrelia burgdorferi , Reservatórios de Doenças , Ixodes , Doença de Lyme , Peromyscus , Animais , Doença de Lyme/tratamento farmacológico , Camundongos , Ixodes/microbiologia , Ixodes/efeitos dos fármacos , Reservatórios de Doenças/microbiologia , Peromyscus/microbiologia , Acaricidas/farmacocinética , Acaricidas/farmacologia , Borrelia burgdorferi/efeitos dos fármacos , Isoxazóis/farmacocinética , Feminino
12.
J Insect Sci ; 24(3)2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38805649

RESUMO

Varroa destructor Oud (Acari: Varroidae) is a harmful ectoparasite of Apis mellifera L. honey bees causing widespread colony losses in Europe and North America. To control populations of these mites, beekeepers have an arsenal of different treatments, including both chemical and nonchemical options. However, nonchemical treatments can be labor intensive, and Varroa has gained resistance to some conventional pesticides, and the use of other chemical treatments is restricted temporally (e.g., cannot be applied during periods of honey production). Thus, beekeepers require additional treatment options for controlling mite populations. The compound 1-allyloxy-4-propoxybenzene (3c{3,6}) is a diether previously shown to be a strong feeding deterrent against Lepidopteran larvae and a repellent against mosquitoes and showed promise as a novel acaricide from laboratory and early field trials. Here we test the effect of the compound, applied at 8 g/brood box on wooden release devices, on honey bees and Varroa in field honey bee colonies located in Maryland, USA, and using a thymol-based commercial product as a positive control. 3c{3,6} had minimal effect on honey bee colonies, but more tests are needed to determine whether it affected egg production by queens. Against Varroa3c{3,6} had an estimated efficacy of 78.5%, while the positive control thymol product showed an efficacy of 91.3%. 3c{3,6} is still in the development stage, and the dose or application method needs to be revisited.


Assuntos
Acaricidas , Varroidae , Animais , Abelhas/parasitologia , Varroidae/efeitos dos fármacos , Maryland , Criação de Abelhas/métodos
13.
J Insect Sci ; 24(3)2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38805657

RESUMO

Despite the use of various integrated pest management strategies to control the honey bee mite, Varroa destructor, varroosis remains the most important threat to honey bee colony health in many countries. In Canada, ineffective varroa control is linked to high winter colony losses and new treatment options, such as a summer treatment, are greatly needed. In this study, a total of 135 colonies located in 6 apiaries were submitted to one of these 3 varroa treatment strategies: (i) an Apivar® fall treatment followed by an oxalic acid (OA) treatment by dripping method; (ii) same as in (i) with a summer treatment consisting of formic acid (Formic Pro™); and (iii) same as in (i) with a summer treatment consisting of slow-release OA/glycerin pads (total of 27 g of OA/colony). Treatment efficacy and their effects on colony performance, mortality, varroa population, and the abundance of 6 viruses (acute bee paralysis virus [ABPV], black queen cell virus [BQCV], deformed wing virus variant A [DWV-A], deformed wing virus variant B [DWV-B], Israeli acute paralysis virus [IAPV], and Kashmir bee virus [KBV]) were assessed. We show that a strategy with a Formic Pro summer treatment tended to reduce the varroa infestation rate to below the economic fall threshold of 15 daily varroa drop, which reduced colony mortality significantly but did not reduce the prevalence or viral load of the 6 tested viruses at the colony level. A strategy with glycerin/OA pads reduced hive weight gain and the varroa infestation rate, but not below the fall threshold. A high prevalence of DWV-B was measured in all groups, which could be related to colony mortality.


Assuntos
Criação de Abelhas , Estações do Ano , Varroidae , Carga Viral , Animais , Varroidae/fisiologia , Abelhas/parasitologia , Abelhas/virologia , Criação de Abelhas/métodos , Acaricidas , Formiatos/farmacologia , Canadá
14.
Environ Sci Pollut Res Int ; 31(24): 35194-35205, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38724845

RESUMO

Strawberries are a favorite fruit for most people, but the residues of pesticides on strawberries might be risky to human health. Tebufenpyrad and milbemectin are broad-spectrum acaricides with insecticide properties authorized for use on strawberries in Egypt. As a result, it is crucial to investigate their residues in the final product to ensure customers' safety. Consequently, field trials were conducted following the Good Agricultural Practices (GAPs) to study the dissipation rate and terminal residues of tebufenpyrad and milbemectin on strawberries. Tebufenpyrad and milbemectin residues in strawberries declined due to first-order decay process, showing significant degradation (88.5% and 94.7%, respectively) after 14 days. Risk assessment study was carried out by comparing the national estimated daily intake (NEDI) to the acceptable daily intake (ADI). The results demonstrated that the dietary risk posed by the residues of tebufenpyrad and milbemectin in strawberry fruits was acceptable for consumers. It is envisaged that the current study's findings would support the safe application of tebufenpyrad and milbemectin to strawberries and perhaps other crops in Egypt and other countries with similar climatic conditions.


Assuntos
Acaricidas , Fragaria , Medição de Risco , Egito , Resíduos de Praguicidas/análise , Humanos
15.
Exp Parasitol ; 261: 108763, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38704016

RESUMO

The brown dog tick or Rhipicephalus sanguineus sensu lato is an ixodid tick, responsible for the dissemination of pathogens that cause canine infectious diseases besides inflicting the direct effects of tick bite. The hot humid climate of Kerala, a south Indian state, is favorable for propagation of tick vectors and acaricides are the main stay of tick control. Though the resistance against synthetic pyrethroids is reported among these species, the status of amitraz resistance in R. sanguineus s. l. in the country is uncertain due to the lack of molecular characterisation data and scarce literature reports. Hence the present study was focused on the phenotypic detection and preliminary genotypic characterisation of amitraz resistance in the R. sanguineus s. l. A modified larval packet test (LPT) on a susceptible isolate was performed to determine the discriminating dose (DD). Further LPT-DD on 35 tick isolates was carried out to detect amitraz resistance robustly, along with that full dose response bioassays on the resistant isolates were performed. The results indicated that amitraz resistance is prevalent with 49 per cent of the samples being resistant. Amplification of exon 3 of octopamine receptor gene from both the susceptible and resistant larval isolates was carried out. Amplicons of ten pooled amitraz susceptible and ten pooled amitraz resistant representative samples were sequenced and analysed, unveiling a total of three novel non-synonymous mutations in the partial coding region at positions V32A, N41D and V58I in phenotypically resistant larval DNA samples. In silico analysis by homology modelling and molecular docking of the mutated and unmutated receptors showed that these mutations had reduced the binding affinity to amitraz. However, lack of mutations in the octopamine receptor gene in three of the pooled low order resistant R. sanguineus s. l. larval samples could be suggestive of other mechanisms associated with amitraz resistance in the region. Hence, further association studies should be carried out to confirm the association of these mutations with target insensitivity in R. sanguineus s. l. ticks, along with exploring the status of metabolic resistance and other mechanisms of resistance.


Assuntos
Acaricidas , Receptores de Amina Biogênica , Rhipicephalus sanguineus , Toluidinas , Animais , Toluidinas/farmacologia , Receptores de Amina Biogênica/genética , Índia , Rhipicephalus sanguineus/genética , Rhipicephalus sanguineus/efeitos dos fármacos , Acaricidas/farmacologia , Larva/genética , Larva/efeitos dos fármacos , Resistência a Inseticidas/genética , Polimorfismo Genético , Genótipo , Cães , Feminino , Doenças do Cão/parasitologia , Simulação de Acoplamento Molecular , Sequência de Aminoácidos , Bioensaio
16.
J Insect Sci ; 24(3)2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38805652

RESUMO

The purpose of this research was to determine how common chemical treatments influence Varroa destructor (Anderson and Trueman) population resurgence rates (defined as time posttreatment for mite populations to reach 3 mites/100 adult bees) in managed honey bee (Apis mellifera L.) colonies seasonally. We conducted 2 experiments that followed the same basic protocol to address this purpose. We established 6 treatment groups in Experiment 1 in the fall of 2014: untreated control, Apivar, Apistan, CheckMite+, ApiLifeVar, and Mite Away II applied to 10 colonies per treatment. In Experiment 2, we applied 8 chemical treatments to each of 4 seasonal (spring, summer, fall, and winter) cohorts of honey bee colonies to determine how mite populations are influenced by the treatments. The treatments/formulations tested were Apivar, Apistan, Apiguard, MAQS, CheckMite+, oxalic acid (dribble), oxalic acid (shop towels), and amitraz (shop towels soaked in Bovitraz). In Experiment 1, Apivar and Mite Away II were able to delay V. destructor resurgence for 2 and 6 months, respectively. In Experiment 2, Apiguard, MAQS, oxalic acid (dribble), and Bovitraz treatments were effective at delaying V. destructor resurgence for at least 2 months during winter and spring. Only the Bovitraz and MAQS treatments were effective at controlling V. destructor in the summer and fall. Of the 2 amitraz-based treatments, the off-label Bovitraz treatment was the only treatment to reduce V. destructor populations in every season. The data gathered through this study allow for the refinement of treatment recommendations for V. destructor, especially regarding the seasonal efficacy of each miticide and the temporal efficacy posttreatment.


Assuntos
Acaricidas , Estações do Ano , Varroidae , Animais , Varroidae/efeitos dos fármacos , Abelhas/parasitologia , Criação de Abelhas
17.
J Insect Sci ; 24(3)2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38805647

RESUMO

The parasitic mite Varroa destructor (Anderson and Trueman) is one of the greatest stressors of Apis mellifera (L.) honey bee colonies. When Varroa infestations reach damaging levels during fall, rapid control is necessary to minimize damage to colonies. We performed a field trial in the US Southeast to determine if a combination of registered treatments (Apivar, amitraz-based; and Apiguard, thymol-based) could provide rapid and effective control of Varroa. We compared colonies that received this combination treatment against colonies that received amitraz-based positive control treatments: (i) Apivar alone; or (ii) amitraz emulsifiable concentrate ("amitraz EC"). While not registered, amitraz EC is used by beekeepers in the United States in part because it is thought to control Varroa more rapidly and effectively than registered products. Based on measurements of Varroa infestation rates of colonies after 21 days of treatment, we found that the combination treatment controlled Varroa nearly as rapidly as the amitraz EC treatment: this or other combinations could be useful for Varroa management. At the end of the 42-day trial, colonies in the amitraz EC group had higher bee populations than those in the Apivar group, which suggests that rapid control helps reduce Varroa damage. Colonies in the combination group had lower bee populations than those in the amitraz EC group, which indicates that the combination treatment needs to be optimized to avoid damage to colonies.


Assuntos
Acaricidas , Timol , Toluidinas , Varroidae , Animais , Toluidinas/farmacologia , Abelhas/parasitologia , Varroidae/efeitos dos fármacos , Varroidae/fisiologia , Timol/farmacologia , Criação de Abelhas/métodos
18.
Vet Parasitol ; 328: 110189, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38714065

RESUMO

In this study we analysed the effect of the temperature, diverse strains of Bacillus thuringiensis, Lysinibacillus sphaericus and nanoformulations with essential plant oils (EONP) on the survival of Sarcoptes scabiei mites derived from naturally-infested Iberian ibex (Capra pyrenaica). In general, mites maintained at 12ºC survived more than those maintained at 35ºC (40.7 hr and 31.2 hr, respectively). Mites with no treatment survived 27.6 h on average. Mites treated with B. thuringiensis serovar. konkukian and geranium EONP showed significant reduction in their survival. Despite the fact that these agents seem to be promising candidates for controlling sarcoptic mange in the field, further research is still needed to get stable, efficient and eco-friendly acaricides.


Assuntos
Acaricidas , Cabras , Sarcoptes scabiei , Animais , Acaricidas/farmacologia , Sarcoptes scabiei/efeitos dos fármacos , Escabiose/tratamento farmacológico , Escabiose/veterinária , Produtos Biológicos/farmacologia , Doenças das Cabras/tratamento farmacológico , Doenças das Cabras/parasitologia , Bacillus thuringiensis/efeitos dos fármacos , Óleos Voláteis/farmacologia
19.
Chemosphere ; 358: 142207, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38697560

RESUMO

Fenazaquin, a potent insecticide widely used to control phytophagous mites, has recently emerged as a potential solution for managing Varroa destructor mites in honeybees. However, the comprehensive impact of fenazaquin on honeybee health remains insufficiently understood. Our current study investigated the acute and chronic toxicity of fenazaquin to honeybee larvae, along with its influence on larval hemolymph metabolism and gut microbiota. Results showed that the acute median lethal dose (LD50) of fenazaquin for honeybee larvae was 1.786 µg/larva, and the chronic LD50 was 1.213 µg/larva. Although chronic exposure to low doses of fenazaquin exhibited no significant effect on larval development, increasing doses of fenazaquin resulted in significant increases in larval mortality, developmental time, and deformity rates. At the metabolic level, high doses of fenazaquin inhibited nucleotide, purine, and lipid metabolism pathways in the larval hemolymph, leading to energy metabolism disorders and physiological dysfunction. Furthermore, high doses of fenazaquin reduced gut microbial diversity and abundance, characterized by decreased relative abundance of functional gut bacterium Lactobacillus kunkeei and increased pathogenic bacterium Melissococcus plutonius. The disrupted gut microbiota, combined with the observed gut tissue damage, could potentially impair food digestion and nutrient absorption in the larvae. Our results provide valuable insights into the complex and diverse effects of fenazaquin on honeybee larvae, establishing an important theoretical basis for applying fenazaquin in beekeeping.


Assuntos
Acaricidas , Microbioma Gastrointestinal , Hemolinfa , Larva , Metaboloma , Animais , Microbioma Gastrointestinal/efeitos dos fármacos , Abelhas/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Hemolinfa/metabolismo , Hemolinfa/efeitos dos fármacos , Metaboloma/efeitos dos fármacos , Acaricidas/toxicidade
20.
Parasitol Res ; 123(5): 204, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38709330

RESUMO

In recent years, there has been growing concern on the potential weakening of honey bees and their increased susceptibility to pathogens due to chronic exposure to xenobiotics. The present work aimed to study the effects on bees undergoing an infection by Nosema ceranae and being exposed to a frequently used in-hive acaricide, amitraz. To achieve this, newly emerged bees were individually infected with N. ceranae spores and/or received a sublethal concentration of amitraz in their diets under laboratory conditions. Mortality, food intake, total volume excrement, body appearance, and parasite development were registered. Bees exposed to both stressors jointly had higher mortality rates compared to bees exposed separately, with no difference in the parasite development. An increase in sugar syrup consumption was observed for all treated bees while infected bees fed with amitraz also showed a diminishment in pollen intake. These results coupled with an increase in the total number of excretion events, alterations in behavior and body surface on individuals that received amitraz could evidence the detrimental action of this molecule. To corroborate these findings under semi-field conditions, worker bees were artificially infected, marked, and released into colonies. Then, they were exposed to a commercial amitraz-based product by contact. The recovered bees showed no differences in the parasite development due to amitraz exposure. This study provides evidence to which extent a honey bee infected with N. ceranae could potentially be weakened by chronic exposure to amitraz treatment.


Assuntos
Nosema , Toluidinas , Animais , Abelhas/efeitos dos fármacos , Abelhas/microbiologia , Abelhas/parasitologia , Nosema/efeitos dos fármacos , Nosema/fisiologia , Acaricidas
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