Abstract:
The effects of formulated essential oils of
Tagetes minuta and Tithonia diversifolia on Rhipicephalus
appendiculatus infesting livestock were evaluated in semifield
experiments. Forty-five zebu cattle naturally infested
with ticks were randomly selected from 15 herds, three
animals from each. Of the three animals within each herd,
one was treated with 1 g of petroleum jelly (control), one
with 1 g of essential oil of T. minuta and one with 1 g of
essential oil of T. diversifolia on the inner side of ear pinna,
the preferred feeding site of R. appendiculatus. Tick
infestation on each treated host animal was monitored daily
for 18 days by counting the number of ticks attached to the
animals. Within 1–4 days post-treatment, the number of
ticks on animals treated with essential oils was reduced by
more than half the original population. By the 5th day posttreatment,
more than 75 and 60% of R. appendiculatus and
other tick species, respectively, became dislodged and
dropped off. A stronger repellent effect was shown by the
essential oil of T. minuta than the essential oil of T.
diversifolia. Mean residual protection afforded by T. minuta
was 12.5 days and for T. diversifolia 7.9 days. There
was no significant difference in the effectiveness of
essential oils between male and female R. appendiculatus.
Both T. minuta and T. diversifolia essential oils affected
several other less dominant but economically important
tick species. Results suggest the potential for essential oil
formulations in integrated pest management of ticks and
associated tick-borne diseases among resource-limited
livestock farmers in tropical Africa.
