Chemical composition and bioactivity of essential oil against the green peach aphid ( Myzus persicae )

The present experiment was conducted to elucidate the chemical composition of essential oil (EO) of a native spontaneous plant, Cotula cinerea Del., in southeastern Algeria and to evaluate its insecticidal effect on the Green Peach Aphid (GPA) Myzus persicae Sulzer. GC–MS and GC-FID analyses showed that this plant was characterized by 35 components, representing eight major constituents, i.e., santolina triene (11.55%), sabinene (5.86%), cineol (6.21%), α-thujone (22.91%), (R)-camphor (7.50%), cis-sabinyl acetate (6.41%), carveol (7.68%), and ipsenol (4.60%). The considered essential oil was characterized by a clear predominance of hydrocarbon compounds chiefly monoterpenes (35.63%), oxygenated monoterpenes (64%), and sesquiterpenes (0.35%). Insecticidal assays showed that the EO was toxic against M. persicae adults recording 75.95% of mortality in the 3rd dose with a lethal concentration (LC 50 ) equal to 302.4 µl where the lethal time (LT 50 ) was 91.6 h. Also, it has a significant repellency showing a high rate in the 2nd dose (64.6%) with a highly significant difference ( p = 0.000). As well as its inhibitory effect on the egg-laying where it has greatly reduced the reproduction potential of M. persicae adults. Obtained data support the possibility to develop C. cinerea oil, especially component specification, as a new natural bio-insecticide.