Effect of Eugenia winzerlingii extracts on Bemisia tabaci and evaluation of its nursery propagation
Efecto de los extractos de Eugenia winzerlingii en Bemisia tabaci y evaluación de su propagación en vivero
The development of natural alternatives to control Bemisia tabaci Genn. (Hemiptera: Aleyrodidae), such as the use of plant derivatives, is a preponderant need in horticultural production systems. Plant extracts and essential oils of several species of the genus Eugenia (Myrtaceae) have shown insecticidal activity. In southern Mexico, leaf extracts from Eugenia winzerlingii showed nematicidal effect but its insecticidal properties have not been explored. Therefore, the objective of this study was to evaluate the insecticidal effect of aqueous and organic extracts from E. winzerlingii leaves on B. tabaci egg, nymph and adult stages, and else to explore its nursery propagation. Then, extracts of this species were obtained by maceration with different polarity solvents. Bioassays were carried out on Capsicum chinense leaves. Mortality assays showed that aqueous and total crude ethanol (TCE) extracts necrosed the eggs (LC50=4.68 mg/mL and 0.21% w/v) whereas hexane, ethyl acetate (ETA), residual ethanol and TCE extracts affected the nymphs (LC50=0.25 - 4.85 mg/mL). In adults, oviposition inhibition by free choice assay indicated that TCE and ETA extracts had major activity (EC50=14.62 and 27.9 µg/cm2, respectively). On other hand, the sexual and vegetative propagation of E. winzerlingii showed that this species can be easily cultivated by seeds. In conclusion, extracts of E. winzerlingii leaves are highly effective in controlling B. tabaci. TCE extract, in particular, was toxic to three stages of B. tabaci. This plant could be a potential alternative to develop a novel botanical insecticide to manage this destructive pest.