Chemical composition and toxicities of the essential oil derived from Hyssopus cuspidatus flowering aerial parts against Sitophilus zeamais and Heterodera avenae

Abstract

Water-distilled essential oil from Hyssopus cuspidatus Boriss (Family: Labiatae) from the aerial parts at the flowering stage was analyzed by gas chromatography-mass spectrometry (GC-MS). Thirty-nine compounds, accounting for 96.78% of the total oil, were identified and the main components of the essential oil of H. cuspidatus flowering aerial parts were thymol (19.65%), trans-pinocamphone (15.30%), γ-terpinene (14.63%), i²-Cymene (7.49%), and β-pinene (6.57%) followed by caryophyllene (4.33%), 1,8-cineol (4.23%) and germacrene D (3.53%). The essential oil of H. cuspidatus possessed contact toxicity against the maize weevil, Sitophilus zeamais adults with an LD50 value of 24.44 μg/adult and also showed pronounced fumigant toxicity against S. zeamais (LC50 = 16.72 mg/L air). The essential oil of H. cuspidatus exhibited strong nematicidal activity against the cereal cyst nematode, Heterodera avenae with an LC50 value of 338.70 μg/mL. The essential oil of H. cuspidatus shows potential to be developed as a possible natural insecticide/nematicide for control of stored product insects/nematodes.   Key Words: Hyssopus cuspidatus, Sitophilus zeamais, Heterodera avenae, nematicidal activity, contact toxicity, fumigant, essential oil composition.