Evaluation of the in-vitro acaricidal activity of aqueous and ethanolic leaf extracts of Annona muricata on Rhipicephalus appendiculatus

Abstract

ABSTRACT In Uganda tick-borne diseases (TBD)are responsible for almost 90% of the total disease control costs and over 60% of total farm inputs which is a big loss to farmers and the economy at large and the principal method employed to control TBDs is the use of synthetic acaricides. However botanical herbs are available locally and if evaluated for acaricidal properties, they can be used to control ticks. This study was carried out with the aim of in vitro acaricidal efficacy evaluation of Annona muricata against Rhipicephalus appendiculatus. The leaves of A. muricata were collected, shade dried and ethanolic and aqueous extracts obtained by maceration. The acaricidal activities of crude ethanolic and aqueous extracts of the leaves of A. muricata were assessed against adult R. appendiculatus ticks and R. appendiculatus larval stages using AIT and LPT, respectively. Five concentrations of both crude extracts 1.25%,2.5%,5%,10% and 20% with two replicates for each were used. The mean percentage mortalities of both the adult ticks and larval stages were recorded as well as the mean percentage egg laying inhibition. Both extracts were also screened for the presence of phytochemicals such as tannins, alkaloids, flavonoids, saponins, anthracenosides and anthocyanosides. The results obtained indicated that both extracts at all concentrations had no effect on the larval stages of the ticks when LPT was carried out. For AIT, aqueous extract had no effect on egg laying inhibition as well as mortality at all concentrations. However, despite the fact that the ethanolic extract had no effect on egg laying inhibition, it exhibited mean percentage adult mortalities of 10% and 35% at concentrations of 100mg/ml (10%) and 200mg/ml (20%) respectively. The ethanolic extract contained alkaloids, tannins, anthocyanosides, flavonoids and anthracenosides. However, the aqueous extract contained all the above except anthracenosides but saponins. The ethanolic