Essential oil in management of coconut rhinoceros beetle Oryctes rhinoceros L.

Plant derived essential oil is used as a component in management of coconut rhinoceros beetle Oryctes rhinoceros L. (Coleoptera: Scarabaeidae). A study was undertaken to evaluate the bioefficacy of essential oil from Ocimum basilicum, Eucalyptus citriodora, Trachyspermum ammi and their major constituent thymolin for management of O. rhinoceros. These essential oils derived from plant parts were characterized and their physiological response and biocidal activity was determined. Basil, citriodora, ajowan oil and thymol caused electrophysiological response in the antennae of O. rhinoceros adults. Behavioural response of beetles was tested in‘Y’ tube olfactometer having a choice between odour arm containing essential oil and control arm having zero air. Orientation of beetles to essential oil laden arm ranged from 15–30%. Over 70–85% of the beetles moved towards the control arm. Citriodora and basil oil inhibited hatching of 70% of eggs and also caused larval mortality. The mean larval mortality ranged from 61–66%. The repellence, ovicidal and growth regulating effect of essential oil offers an ecofriendly option in management of coconut rhinoceros beetle.