Aphidicidal activities of Melaleuca styphelioides Sm. essential oils on three citrus aphids: Aphis gossypii Glover; Aphis spiraecola Patch and Myzus persicae (Sulzer)

Essential oils are a mixture of various compounds that can have acted against insect pests through complex mechanisms. Their constituents were shown to be a potent source of biological pesticides. The aims of the present study are to characterize the chemical composition and evaluate the aphidicidal activities of Tunisian Melaleuca styphelioides leaves essential oil. Fumigant and contact toxicities were determined against three major aphid infecting citrus trees: Aphis gossypi, Aphis spiraecola and Myzus persicae. The chemical composition of this oil was characterized by GC-MS. The major common compounds were caryophyllene oxide (23.42%), spathulenol (20.5%), isoaromadendrene epoxide (7.45%), ledol (5.98%), and α-pinene (3.82%).The results showed that M. styphelioides essential oil has a good fumigant and contact toxicity against the three citrus aphids tested. The highest activity was registered on A. spiraecola nymphs (LC50 = 44.72 μL/L air for the fumigant activity and 115.93 μL/L for the contact toxicity). The adults of A. gossypii seem to be more resistant to essential oil in the contact bioassay with an LC50 = 3660.99 μL/L. Overall, our work proposes the use of the M. styphelioides essential oil as contact and fumigant bio-insecticides against resistant citrus aphids.