Nematicidal investigations of some essential oils from citrus plants

Abstract

Essential oils from citrus plants are getting increasing interest in the agricultural pest management. Numerous studies demonstrate their antibacterial, antifungal, insecticidal and nematicidal properties. This study was conducted to determine the activity of the essential oils from citrus plants (bergamot, bitter orange, grapefruit, mandarin, orange, and lemon) against the rhabditid nematode Panagrolaimus sp. In vitro nematicide screening was performed with aqueous solutions of essential oils in serial dilutions (1-0.0078%). The contact bioassay was done in small glass Petri dishes containing 3 ml of solution and 50 nematodes at 18oC. The experiment was carried out in five replicates. The lethal effect was monitored after 24h. Median lethal concentration (LC50) was calculated using the Probit analysis. The best nematicidal activity performed the essential oil from lemon, followed by bergamot. The bitter orange had better nematicidal properties than mandarin and grapefruit essential oils. The least activity demonstrated orange oil.