Acaricidal Activity of Volatile oil from Lemon and Citronella Grasses on Tropical Cattle Ticks

Abstract

Volatile oil was obtained from lemon grass (Cymbopogon citratus stapf.) and citronella grass (Cymbopogon nardus Rendle.) leaves by steam distillation. The yields were 0.39% and 0.68% from the fresh leaves of lemon and citronella grasses respectively. Oil yield from dried leaves of lemon and citronella grasses were 0.52% and 1.20%, respectively. The stems and roots gave very less amount of oil. The oil was diluted with 95% ethanol and tested for acaricidal activity on larvae and engorge female cattle ticks (Boophilus microplus) by dipping method. The oil from fresh lemon grass showed high larvicidal activity (1-2 h after dipping) at the concentration of 1:8, 1:12 and 1:16 (oil/ethanol; V/V), while the oil from fresh citronella grass exhibited high activity at concentration of 1:8 and 1:12 (V/V). On the engorge female ticks, the lemon grass oil concentration of 1:2, 1:3 and 1:4 (oil/ethanol; V/V) exhibited high acaricidal activity on 5 days after dipping, but the citronella oil showed high activity at concentration of 1:2 and 1:3. The oil from dried leaves of both grasses showed weaker acaricidal activity on both larvae and adult ticks. In vivo acaricidal bioassay, the ethanol dilution 1:3 (V/V) of both oils were tested by spraying to the tick on cattle. The pre-engorge stage ticks collapsed and died on cattle’s skin while the collected engorge female ticks could not laid and died at 5 days after spraying. This indicates that volatile oil from lemon and citronella grasses can be practically used for controlling cattle ticks.