GC/MS Analysis of Eucalyptus globulus L. (Myrtaceae) Leaves Essential Oil from Algeria and their Insecticidal Activity Against Adults of Bactrocera oleae (Rossi) (Diptera; Tephritidae)

Abstract

In this study, the essential oil of leaves Eucalyptus globulus (Myrtales: Myrtaceae) was analyzed by gas chromatography/mass spectrometry (GC/MS) and their potential insecticidal against the olive fruit fly Bactrocera oleae (Diptera: Thephritidae) was investigated. The essential oil yield was 0.36 ± 0.03% (w/w). A total of 41 compounds (99.99%) were identified. (-)-spathulenol (32.66%), o-cymene (28.30%) and (+-)-cryptone (12.13%) were major constituents. The toxic impact of essential oil of E. globulus was assessed against B. oleae adults through two toxicity tests (contact and fumigation). B. oleae was more susceptible to E. globulus and adult mortality increased according to concentration and exposure time. In the contact toxicity, the lethal concentration LC₅₀ values were 0.24 µL/cm² and 0.15 µL/cm² in 24 h and 48 h, respectively and LC₉₀ values of 0.64 µl/cm² and 0.33 µL/cm² were obtained in 24 h and 48 h, respectively. In fumigation assay on olive fruit fly adults, LC₅₀ values were 14.05 μL/L air and 5.71 μL/L air at 24 h and 48 h, respectively and LC₉₀ values of 51.53 μL/L air and 21.64 μL/L air at 24 h and 48 h, respectively. The findings of current study show that use of essential oil of leaves of E. globulus against B. oleae is considered as an eco-friendly alternative natural insecticide.

Keywords:

• Eucalyptus globulus
• Bactrocera oleae
• Essential oil
• Contact
• Fumigation