Composition and insecticidal activity of the essential oil of Croton grewioides Baill. against Mexican bean weevil (Zabrotes subfasciatus Boheman).

The essential oils of leaves and stems of Croton grewioides Baill. of the agreste region of Pernambuco, Brazil, were obtained by hydrodistillation and analyzed by GC and GC/MS. Twenty-two components were identified, which represented 99.8% and 98.6% of the total constituents in the leaf and stem oil, respectively. Croton grewioides produced an oil with a predominance of phenylpropanoid compounds, whose principal component was (E)-anethole (65.5% in the leaf and 47.8% in the stem). Other major components found in the leafoil were methyl eugenol (10.6%) and (E)-methyl isoeugenol (4.7%). Other components identified in the stem oil were (E)-methyl isoeugenol (30.0%), cadalene (8.4%) and methyl eugenol (4.6%). The insecticidal activity of C. grewioides was evaluated against Mexican bean weevils, Zabrotes subfaciatus (Boheman) resulting in a LC50 for the leaf oil, which was 3.4 times less than that obtained from the stem oil.