An <i>in vitro</i> study of the acaricidal efficacy of aqueous crude extracts of three ethno-veterinary plants on larvae of <i>Rhipicephalus appendiculatus</i> and <i>Amblyomma hebraeum</i>

Abstract

In vitro acaricidal efficacy trials, of the plants; Blumea decurrens, Carica papaya and Manihot esculenta against larvae of Rhipicephalus appendiculatus and Amblyomma hebraeum were conducted using the larval packet test assay. The extracts were used at concentrations of 0.156, 0.625, 1.25, 2.5, 5 and 10%. Mortalities of R. appendiculatus larvae ranged from 10.5% to 81.7% for C. papaya and M. esculenta respectively. For A. hebraeum, these mortalities ranged from 1.4% to 26.5% with B. decurrens and M. esculenta respectively. The LC₅₀ values for M. esculenta, C. papaya and B. decurrens were 3.6, 7.7 and 4.4 mg/ml respectively against R appendiculatus, and were 178.3, 148.1 and 354.3 mg/ml against A. hebraeum for M. esculenta, C. papaya and B. decurrens respectively. Manihot esculenta exhibited significantly (P<0.05) greater acaricidal efficacy than the other plants. These results suggest that the crude extracts of M. esculenta have potential acaricidal properties and warrant further investigation.

Keywords: Acaricidal, Crude extracts, entho-veterinary plants, Rhipicephalus appendiculatus, Amblyomma hebraeum