Phytochemical evaluation and nematicide effect of a dry leaves aqueous extract of Eucalyptus globulus against Pratylenchus vulnus infecting apple

The nematicide effect of an aqueous extract from dried leaves of Eucalyptus globulus was evaluated against the root lesion nematode Pratylenchus vulnus in vitro and in vivo trials. In both experiments, the application of four concentrations of a dried leaf aqueous extract (30 g/100 mL: 100%, 20 g/100 mL :60%, 10 g/100 mL: 30%, 5 g/100 mL: 15%; w/v) significantly reduced the nematode number of females and males in roots of the apple rootstock MM106. In vitro tests showed that the highest mortality was recorded with the undiluted concentration (96%) after 72 h of exposure time. Results of in vivo experiment revealed also that the concentration 100% has significantly increased the reduction rates of the nematode population of females and males (84.43% and 91.40%, respectively) compared to the other concentrations. The chemical treatment with Oxamyl G has significantly reduced the female and male population by 98.30% and 100%, respectively. The chemical analysis of dried leaves of Eucalyptus globulus showed high levels of total phenol and total flavonoid contents and exhibited high antioxidant capacity. The obtained results suggest that aqueous extracts of Eucalyptus globulus leaves have a promising nematicide potential against P. vulnus.