Chemical composition and activity of essential oils of Albanian coniferous plants on plant pests

The present study was conducted to evaluate and compare the chemical composition and bio activity on different insect organisms of essential oils from four Albanian coniferous plants. The phytochemical analysis carried out using GC-MS showed that the oils were constituted mainly by monoterpenes, sesquiterpenes and diterpenes. Chemical analysis identified 16 constituents in Black pine and Silver fir, 17 constituents in Dauglas fir, while the analysis allowed identification of 28 constituents in Juniperus berry. Main costituents of the essential oils were α-pinene and c-verbenol in Black pine; β-pinene, α-fenchone and α-pinene in Douglas fir; limonene, β-pinene, α-pinene, and camphene in Silver fir; α-pinene, sabinene, β-myrcene in Juniperus berry. The oils showed varying degree of insecticidal activity. Juniperus berry and Silver fir affected the settling behavior of the aphids Myzus persicae and Rhopalosiphum padi respectively. Black pine oil presented significant activity against the tick Hyalomma lusitanicum and the root-knot nematode Meloidogyne javanica. The ixodicidal effect of this essential oil was explained by its content in c-verbenol, while this compound and binary combinations of α-pinene and c-verbenol were not nematicidal, suggesting synergic effects between minor components of Black pine essential oil.