Bioactivity of selected essential oils from medicinal plants found in Fiji against the Spiralling whiteflies (<em>Aleurodicus dispersus</em> Russell)

Abstract

The concentration of essential oil solutions [0.25%, 0.5% and 5% (v/v)] of five medicinal plants found in the South Pacific (Fiji) were subjected to the whitefly (Aleurodicus dispersus Russell) in order to assess eventual control activities, by both fumigant and repellent tests. The essential oil of Ocimum tenuiflorum L. exhibited the strongest fumigant activity against the Spiralling whiteflies with an LC50 value of 0.003% followed by the essential oil of Cymbopogon citratus (DC.) Stapf. (LC50 = 0.004%), Cananga odorata (Lam.) Hook F. and Thoms (LC50 = 0.050%), Murraya koenigii (L.) Spreng. (LC50 = 0.113%), and Euodia hortensis forma hortensis (LC50 = 0.114%). The essential oil of M. koenigii (RI=52%) and C. citratus (RI=52%) at 5% (v/v) concentration were found to have a higher repellent toxicity against the Spiralling whiteflies. The chemical composition of the selected essential oils was also determined using GC-MS. The trend in the chemical constituent of essential oils revealed that the phenolic and alcoholic compounds were the major groups of contributors to the tested activities. Thus, these data suggested that essential oils from the selected medicinal plants found in the South Pacific (Fiji) have the potential to be employed in the pesticidal activities.