Influence of the acaricide emulsion pH on the effectiveness of spray products to control the cattle tick: laboratory and field investigations

Nicaretta, João Eduardo; Ferreira, Lorena Lopes; Cavalcante, Alliny Souza de Assis; Zapa, Dina María Beltrán; Heller, Luciana Maffini; Trindade, Artur Siqueira Nunes; Morais, Igor Maciel Lopes de; Salvador, Vanessa Ferreira; Leal, Luccas Lourenzzo Lima Lins; Silva, Francisca Letícia Vale da; Gontijo, Lídia Mendes de Aquino; Couto, Luiz Felipe Monteiro; Soares, Vando Edésio; Monteiro, Caio Márcio de Oliveira; Lopes, Welber Daniel Zanetti

doi:10.1007/s00436-023-07927-y

Cited by 2 publications

(4 citation statements)

References 15 publications

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“…The nymphs showed a tolerance to the combination of chlorpyrifos + cypermethrin + citronellal (RR > 2), which could possibly be explained by their tolerance to the individual classes of pyrethroids and organophosphates. Although these combinations are not licensed for use on horses according to the package insert, they have been used on dairy cattle in the experimental farm where the A. sculptum GYN strain was collected [17][18][19]25,26]. This may suggest that the constant use of acaricides targeting R. microplus on cattle may have resulted in the selection of a tolerant A. sculptum population.…”

Section: Discussionmentioning

confidence: 99%

“…For this study, the ticks collected in the PNE (namely PNE strain) were considered to be the susceptible strain in the immersion tests for a statistical comparison with the ticks collected in the experimental farm (namely, the GYN strain). This experimental farm (16 • 35 42 S, 49 • 16 50 W) is in the municipality of Goiânia (capital of Goiás) (421.36 km from PNE) and consists of an area where chemical acaricides are often used on dairy cattle [17][18][19]. In addition to R. microplus, A. sculptum is commonly found on dairy cattle due to their close contact with capybaras.…”

Section: Study Locationsmentioning

confidence: 99%

“…Combinations of pyrethroids and organophosphates (chlorpyrifos + cypermethrin + citronellal and chlorpyrifos + fenthion + cypermethrin) and amitraz were also included. Although they are not specifically indicated for horses, their inclusion was justified by the direct coexistence between capybaras and cattle in the experimental farm, where exposure to these acaricides occurs [17][18][19]. Indeed, acaricides, such as chlorpyrifos + high-cis cypermethrin, flumethrin, and chlorpyrifos + ethion + alpha-cypermethrin, have long been used to control R. microplus on dairy cattle in the experimental farm [17][18][19]25,26].…”

Section: Acaricides and Lethal Concentrationsmentioning

confidence: 99%

“…Although they are not specifically indicated for horses, their inclusion was justified by the direct coexistence between capybaras and cattle in the experimental farm, where exposure to these acaricides occurs [17][18][19]. Indeed, acaricides, such as chlorpyrifos + high-cis cypermethrin, flumethrin, and chlorpyrifos + ethion + alpha-cypermethrin, have long been used to control R. microplus on dairy cattle in the experimental farm [17][18][19]25,26]. The selection of these acaricides was also relevant for comparison with a previous study conducted in Goiás [16].…”

Section: Acaricides and Lethal Concentrationsmentioning

confidence: 99%

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Susceptibility of Amblyomma sculptum, Vector of Rickettsia rickettsii, Ticks from a National Park and an Experimental Farm to Different Synthetic Acaricides

Cardoso,

Carvalho,

Dias

et al. 2023

Pathogens

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Amblyomma sculptum is a relevant tick species from a One Health perspective, playing an important role as a vector of Rickettsia rickettsii, the main agent of spotted fever rickettsiosis in Brazil. In this study, we evaluated the susceptibility of two A. sculptum populations from Goiás state (midwestern Brazil) to different acaricides. The first tick population (GYN strain) originated from an experimental farm, where the ticks are annually exposed to acaricides. The second (PNE strain) was collected in a national park (Emas National Park), where the ticks had not been exposed to acaricides. Immersion tests were conducted with 21-day-old laboratory-reared larvae and nymphs originating from adult ticks collected in the areas mentioned above. The chosen acaricides were two synthetic pyrethroids (cypermethrin and deltamethrin), one organophosphate (chlorfenvinphos), one formamidine (amitraz), and two combinations of pyrethroids and organophosphates (cypermethrin, chlorpyrifos and citronellal; cypermethrin, fenthion and chlorpyrifos). Mortality data were used to determine the lethal concentration (LC) values at which 50%, 90%, and 99% of the ticks died (LC50, LC90, and LC99, respectively), and resistance ratios (RR) were calculated based on the LC values. The RR revealed differences between the acaricide-exposed (GYN) and unexposed (PNE) tick strains. The PNE strain larvae and nymphs were susceptible to all the tested acaricides. The GYN strain larvae were tolerant to cypermethrin, whereas the nymphs were tolerant to deltamethrin, chlorfenvinphos, and the combination of cypermethrin, chlorpyrifos, and citronellal (2 < RR ≤ 10). The GYN strain nymphs were resistant to amitraz (RR > 10). This is the first report of A. sculptum nymphs with resistance to amitraz and tolerance to deltamethrin, chlorfenvinphos, and the combination of cypermethrin, chlorpyrifos, and citronellal.

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