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

Parasitology research 2023 Oct

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The current work evaluated the efficacy of 10 commercial acaricides in different pHs (4.5, 5.5, and 6.5) in laboratory (adult immersion tests (AIT), pH evaluation over time) and field assays (tick counts and efficacy). In the AIT (n=70), higher efficacies were obtained when the acaricide emulsion had a more acidic pH (4.5), mainly for two combinations of pyrethroids + organophosphate (acaricide 3 and acaricide 9). For amidine, a higher pH (6.5) showed a higher efficacy. Over time, there was a trend in the pH of these emulsions increasing. When the efficacy of chlorpyrifos + cypermethrin + piperonyl butoxide (acaricide 3) at different pHs was evaluated over time (0, 6, 12, and 24h) by AIT, the less acidic pH (6.5) showed a strongly variation in the acaricide efficacy range. The mean pH of the water samples from different regions of Brazil was 6.5. In the field, the association of pyrethroid + organophosphates (acaricide 9) with pH of 4.5 and 5.5 were more effective in tick control than the emulsion prepared with this same spray formulation at pH 6.5. The pH of the acaricide emulsions is an important point of attention and is recommended that the veterinary industry start to develop/share information regarding how the pH can affect the acaricide efficacy. © 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Citation

João Eduardo Nicaretta, Lorena Lopes Ferreira, Alliny Souza de Assis de Cavalcante, Dina María Beltrán Zapa, Luciana Maffini Heller, Artur Siqueira Nunes Trindade, Igor Maciel Lopes de Morais, Vanessa Ferreira Salvador, Luccas Lourenzzo Lima Lins Leal, Francisca Letícia Vale da Silva, Lídia Mendes de Aquino, Luiz Felipe Monteiro Couto, Vando Edésio Soares, Caio Márcio Oliveira Monteiro, Welber Daniel Zanetti Lopes. Influence of the acaricide emulsion pH on the effectiveness of spray products to control the cattle tick: laboratory and field investigations. Parasitology research. 2023 Oct;122(10):2267-2278