RESUMO
The aim of this work was to develop a technique of acaricides evaluation by immersion of larvae. Larvae were obtained from 30 engorged females of Riphicephalus (Boophilus) microplus were collected in a ranch in Lages, Santa Catarina state, Brazil. Larvae were obtained from 10mg of eggs placed into 5ml disposable syringes, previously prepared and kept under controlled conditions of laboratory, and collected between the third and the twelfth day of oviposition. Seven to ten days old larvae were submitted to the acaricide laboratory test, in ten replications, by their immersion in eight dilutions of commercial acaricides (amitraz or cypermethrin), for 30 seconds; for each replication and commercial product, a control group was immersed in distilled water. Results were evaluated 24 hours after each treatment by counting the number of live and dead larvae. The mean LD50 values and standard error of the mean for cypermethrin and amitraz were 2.99 ± 0.36 and 17.22 ± 4.20 ppm, respectively, for a confidence interval of 95 percent. The proposed acaricide laboratory test procedures by larvae immersion offered promising results for the evaluation of acaricides.
Objetivou-se desenvolver uma técnica de avaliação de carrapaticidas por imersão de larvas de Riphicephalus (Boophilus) microplus. As larvas foram obtidas a partir de ovos de 30 teleóginas coletadas em bovinos de uma propriedade rural do município de Lages, SC, Brasil, os quais foram acondicionados em alíquotas de 10mg por seringa descartável de 5ml, previamente preparadas e mantidas em câmara climatizada até a eclosão. Larvas com sete a dez dias de idade foram submetidas à imersão por 30 segundos em oito diluições de produtos carrapaticidas comerciais à base de amitraz e de cipermetrina, cada uma com dez repetições, sendo mantido um grupo controle para cada repetição e produto, o qual foi imerso em água destilada. A leitura foi realizada 24 horas após o tratamento com a contagem de larvas vivas e mortas. A média de DL50 para cipermetrina foi de 2,99ppm e o erro padrão de 0,36 e para o amitraz foi de 17,22ppm e o erro padrão de 4,20, com intervalo de confiança (IC) 95 por cento.
Assuntos
Animais , Inseticidas , Piretrinas , Rhipicephalus , ToluidinasRESUMO
The aim of this work was to develop a technique of acaricides evaluation by immersion of larvae. Larvae were obtained from 30 engorged females of Riphicephalus (Boophilus) microplus were collected in a ranch in Lages, Santa Catarina state, Brazil. Larvae were obtained from 10mg of eggs placed into 5ml disposable syringes, previously prepared and kept under controlled conditions of laboratory, and collected between the third and the twelfth day of oviposition. Seven to ten days old larvae were submitted to the acaricide laboratory test, in ten replications, by their immersion in eight dilutions of commercial acaricides (amitraz or cypermethrin), for 30 seconds; for each replication and commercial product, a control group was immersed in distilled water. Results were evaluated 24 hours after each treatment by counting the number of live and dead larvae. The mean LD50 values and standard error of the mean for cypermethrin and amitraz were 2.99 +/- 0.36 and 17.22 +/- 4.20 ppm, respectively, for a confidence interval of 95%. The proposed acaricide laboratory test procedures by larvae immersion offered promising results for the evaluation of acaricides.
