Attraction response of adult Rhipicephalus appendiculatus and Rhipicephalus pulchellus (Acari: Ixodidae) ticks to extracts from Calpurnia aurea (Fabaceae)

Experiments were carried out to investigate the response of two tick species Rhipicephalus pulchellus Gerstaker, 1873 and Rhipicephalus appendiculatus Neumann, 1901 to three different extracts (acetone, aqueous and oil) of the dried leaves of Calpurnia aurea (Aiton) Benth in both an inverted glass tube and a dual choice T-olfactometer. The oil extract at 50 and 100 mg/ml attracted 46.7% and 65.9% of R. appendiculatus, respectively, in the inverted glass tube assay, which was comparable to 47.8% of the attraction-aggregation-attachment pheromone (AAAP) used as positive control. At a dose of 100 mg/ml the oil extract attracted 52.4% of R. pulchellus in the T-olfactometer bioassay. The relative attraction of both tick species to plant extract was also tested in semi-field plot experiments using a trap baited with different concentrations of emulsifiable extract of C. aurea. A dose of 100 mg/ml attracted 52.2% of R. pulchellus and 44.4% of R. appendiculatus from a distance of 1 m while 14.4% of R. pulchellus and 12.2% of R. appendiculatus were attracted from 5 m distance at the same dose. Addition of CO2 to the plant extract-baited-trap at the dose of 100 mg/ml increased the range of attraction of adult R. pulchellus (44.4% from 5 m distance) and up to 33.3% of adult R. appendiculatus tick from a distance of 4 m. The results of this study suggest that extracts from C. aurea can potentially be used as baits in a trap for the control of ticks in the field.