Análise da eficácia de acaricidas sobre o carrapato Boophilus microplus, durante a última década, na região sul do Rio Grande do Sul

Farias, Nara Amélia da Rosa; Ruas, Jerônimo Lopes; Santos, Tânia Regina Bettin dos

doi:10.1590/s0103-84782008000600032

Cited by 28 publications

(27 citation statements)

References 4 publications

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“…This is in agreement with the findings of Farias et al (2008) for farms in the state of Rio Grande do Sul.…”

Section: Resultssupporting

confidence: 93%

“…Over the course of a decade, Farias et al (2008) studied the susceptibility/resistance of the cattle tick, as well as the dynamics of use of the various groups of commercially available acaricides, in southern Rio Grande do Sul. The authors noted that the products that were most commonly used during the first three-year period were pyrethroid-based acaricides, which resulted in the selection of pyrethroid-resistant populations.…”

Section: Introductionmentioning

confidence: 99%

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Resistance to cypermethrin and amitraz in Rhipicephalus (Boophilus) microplus on the Santa Catarina Plateau, Brazil

Veiga¹,

Souza

Bellato

et al. 2012

Rev. Bras. Parasitol. Vet.

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With the objective of evaluating Rhipicephalus (Boophilus) microplus resistance to cipermetrina and amitraz, were collected engorged tick females from cattle on 20 farms on the Santa Catarina Plateau, in southern Brazil, between January of 2004 and May of 2006. Were also received 20 groups of engorged R. (B.) microplus females, collected by cattle farmers requesting acaricidal efficacy (AE) testing. Were performed in vitro tests, which consisted of immersing engorged females in cypermethrin (0.015%) and in amitraz (0.025%). An AE ≥95% was considered indicative of effectiveness. Of the 20 collected groups, 18 (90%) showed cypermethrin resistance and 1 (5%) showed amitraz resistance. Of the 20 received groups, 19 (95%) showed cypermethrin resistance and 2 (10%) showed amitraz resistance. The AE of cypermethrin was found to be ≥95%, 85-94%, and 55-64%, respectively, in 4 (57.1%), 2 (28.6%), and 1 (14.3%) of 7 reference groups, collected in the 1997-2001 period. The AE of amitraz was ≥95% in all of those groups. Among the groups of specimens received for analysis in that period, the AE of amitraz was ≥95% in 6 (85.71%) and 75-84% in 1 (14.28%). R. (B.) microplus resistance to acaricides is increasing on the Santa Catarina Plateau.Keywords: Rhipicephalus (Boophilus) microplus, cattle tick, acaricide resistance. ResumoCom os objetivos de avaliar a resistência do Rhipicephalus (Boophilus) microplus à cipermetrina e ao amitraz no Planalto Catarinense, no período de janeiro de 2004 a maio de 2006, foram coletadas teleóginas em bovinos de 20 propriedades onde os produtores autorizaram a coleta (amostras por conveniência) e recebidas teleóginas de mais 20 propriedades com objetivo de diagnóstico de eficácia. Os testes in vitro foram realizados por imersão de teleóginas em cipermetrina (0,015%) e amitraz (0,025%). Considerando a eficácia igual ou superior a 95%, das 20 propriedades amostradas, 18 (90%) apresentaram resistência à cipermetrina e uma (5%) ao amitraz. Das 20 propriedades com teleóginas para diagnóstico, 19 (95%) apresentaram resistência à cipermetrina e duas (10%) ao amitraz. No período de agosto de 1997 a dezembro de 2001, das sete amostras coletadas, em quatro (57,1%) a eficácia da cipermetrina foi ≥95%, em duas (28,6%) entre 85% e 94% e em uma, (14,3%) entre 55% e 64%. A eficácia do amitraz foi ≥95%, em teleóginas de todas as propriedades. Nas amostras para diagnóstico, seis (85,71%) apresentaram eficácia para o amitraz ≥95% e uma (14,28%) entre 75% e 84%. A resistência desse ixodídeo aos carrapaticidas testados é crescente no Planalto Catarinense.Palavras-chave: Rhipicephalus (Boophilus) microplus, carrapato dos bovinos, resistência a acaricidas.

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“…This is in agreement with the findings of Farias et al (2008) for farms in the state of Rio Grande do Sul.…”

Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Resistance to cypermethrin and amitraz in Rhipicephalus (Boophilus) microplus on the Santa Catarina Plateau, Brazil

Veiga¹,

Souza

Bellato

et al. 2012

Rev. Bras. Parasitol. Vet.

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“…Amitraz is the acaricide most used in the southern region of the state of Rio Grande do Sul, Brazil (VARGAS et al, 2003;FARIAS et al, 2008;SANTOS et al, 2009). It has some advantages over other acaricides, such as low toxicity to cattle and short withdrawal periods for milk (one day) and meat (14 days).…”

Section: Introductionmentioning

confidence: 99%

Comparison of three larval bioassays to evaluate susceptibility of Rhipicephalus (Boophilus) microplus to amitraz

Santos

Klafke²,

Pappen

et al. 2013

Rev. Bras. Parasitol. Vet.

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Field samples of Rhipicephalus (Boophilus) microplus from the state of Rio Grande do Sul, Brazil, were assessed using the following methods: larval packet test (LPT), larval immersion test (LIT) and syringe immersion test (SIT). The following parameters were determined for each population and for the Mozo susceptible reference strain: lethal concentration for 50% (LC 50 ) with its 95% confidence interval (95% CI), regression line slope and resistance ratio (RR). Using the LPT, only one population was susceptible to amitraz, presenting a RR of 1.9. Using the same technique, the other populations presented RRs of between 92.9 and 3445.8 and were considered resistant. The LC 50 of the Mozo strain calculated using the LPT, LIT and SIT was 2.9, 27.3, and 52.7 µg/mL, respectively. In general, a good fit to the probit statistical model was only achieved using the LPT. The results obtained in this study impair recommendations for using the LIT and SIT to diagnose amitraz resistance in R. (B.) microplus populations. Additional studies are required to improve the sensitivity of these tests in relation to the LPT.Keywords: Rhipicephalus (Boophilus) microplus, amitraz, bioassays, resistance diagnosis. ResumoAmostras de Rhipicephalus (Boophilus) microplus coletadas à campo no Rio Grande do Sul, Brasil, foram analisadas pelos seguintes métodos: teste do pacote de larvas (TPL), teste de imersão de larvas (TIL) e teste de imersão em seringas (TIS). Os seguintes parâmetros foram determinados para cada população e para a amostra referência suscetível Mozo: concentração letal para 50% (CL 50 ) e seu intervalo de confiança de 95% (IC95%), inclinação da reta de regressão e os fatores de resistência (FR). Pelo TPL, apenas uma população foi sensível ao amitraz, com FR de 1,9. Utilizando a mesma técnica, as outras amostras apresentaram FR entre 92,9 e 3445,8 sendo consideradas resistentes. As CL 50 da cepa Mozo calculadas por meio do TPL, TIL e TIS foram 2,9, 27,3 e 52,7 µg/mL, respectivamente. De forma geral, a adequação ao modelo estatístico de probitos só foi alcançada com o uso do TPL. Os resultados obtidos no presente estudo limitam a recomendação de uso do TIL e TIS para diagnóstico de resistência ao amitraz em populações de R. (B.) microplus. Estudos adicionais são necessários para aprimorar a sensibilidade destes testes em relação ao LPT.Palavras-chave: Rhipicephalus (Boophilus) microplus, amitraz, bioensaio, diagnóstico de resistência.

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“…M. anispliae is the female antagonist engorged of R. microplus, therefore the effective agent in cattle tick biocontrol in tropical regions. In the current study, no other fungus was superior to Metarhizium anisopliae, a reference fungus currently used in biological control of ticks [31][32][33][34][35][36][37].…”

Section: Resultsmentioning

confidence: 99%

Selection of Filamentous Fungi for the Biocontrol of Rhipicephalus (Boophilus) Microplus in Tropical Regions

Abrão¹

2017

JDVAR

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Rhipicephalus microplus is an ectoparasite that causes significant losses to livestock due to spoliation of cattle and the high cost of current control techniques. The control of this parasite is chemically accomplished, but the incorrect use of this method is causing resistance in this species. An alternative to control would be the use of fungi, as they do not need to be ingested by the host, being only necessary to have contact with the target such that it can grow and colonize. Thus, the present study aimed to isolate, identify and select efficient fungal strains in the biological control of Rhipicephalus microplus in tropical weather, such as found in Brazil. Soil and Brachiaria brizantha forage samplings were carried out for isolation, quantification and identification of fungal species. Engaged females of R. microplus were collected for the bioassay of colonization rate, hatchability of eggs and production of mycotoxins. A total of 2x10 -3 CFU g -1 fungi were found and five genera were identified. Aspergillus spp. was the most frequent genus amidst the isolates obtained from both environments. The forage presented a greater amount of fungal colonies.g -1 when compared to the soil. We identified entomopathogenic, saprophytic, pathogenic and keratinophilic species with biotechnological potential as well as for use for biological control. Aspergillus was the most prevalent genus in both soil and forage of tropical regions. Elevated fungal variety was observed in the ecosystems we studied. Metarhizium anisopliae efficiently colonized the parasites in an 80% rate, and differed from other treatments (p< 0.01). These study open doors for investigations concerning the evaluation of other fungi colony counting's, forms of manipulation and other bioassays.Keywords: Dairy cattle; Tick; Biological control; In vitro tests; Microbiology; R. microplus; Rhipicephalus microplus; Aspergillus IntroductionTicks are ectoparasites characterized mainly by blood feeding, independently of family, genus or species [1], and the species Rhipicephalus microplus causes substantial losses for beef and milk cattle due to spoliation of cattle and the high cost of current control techniques [2][3][4]. These parasites have a lifecycle in the host and another in the pasture, and only females fill with blood, after they release themselves from the host and fall to the ground, where they seek a dark and humid place, suitable to lay their eggs [5]. The weather conditions in Brazil contribute to the development of the ectoparasite, allowing ticks populations to be virtually established in the entire country [6]. The chemical control is currently the preferred for the combat of ticks; however, the incorrect use of this method favors the occurrence of multiple or cross resistance [7,8]. In addition, the permanence of residues in animals and their products, thereby, alternatives to the control of this parasite are highly relevant [9].There are several natural enemies that contribute to the control of this parasite in the host or in the soi...

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Análise da eficácia de acaricidas sobre o carrapato Boophilus microplus, durante a última década, na região sul do Rio Grande do Sul

Cited by 28 publications

References 4 publications

Resistance to cypermethrin and amitraz in Rhipicephalus (Boophilus) microplus on the Santa Catarina Plateau, Brazil

Resistance to cypermethrin and amitraz in Rhipicephalus (Boophilus) microplus on the Santa Catarina Plateau, Brazil

Comparison of three larval bioassays to evaluate susceptibility of Rhipicephalus (Boophilus) microplus to amitraz

Selection of Filamentous Fungi for the Biocontrol of Rhipicephalus (Boophilus) Microplus in Tropical Regions

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