Effectiveness of bastard oleaster (Elaeagnus latifolia) extracts against the nymph of mealybug (Phenacoccus manihoti)
Bastard oleaster (Elaeagnus latifolia) is sometimes gathered from subtropical wild for local use as food, medicine and fuel. The objective of this study was to investigate the insecticidal properties of extracts from leaves and fruits of bastard oleaster against the nymph of mealybug (Phenacoccus manihoti) by using leaf dipping method. The different extracts of bastard oleaster as water extract by decoction method, ethanol and hexane extracts by percolation and Soxhlet methods were applied with various concentrations; 0 (5% tween-20 water) 1, 2, 3, 4 and 5% (w/v), and imidacloprid insecticide used as positive control. Then the insect mortality was observed at 24 and 48 h, as well as the repellent index (%RI) was observed at 24 h. The results showed that ethanolic extract from bastard oleaster fruits by Soxhlet method and leaves by percolation method were highly effective in killing the nymph of mealybug with the LC50 at 48 h for 2.64 and 2.83%, respectively. The bastard oleaster leaves extracted by percolation and Soxhlet at 5% concentrations showed rather strong effect in repellence when the nymph of mealybug with >52% RI was found within 24 h. In addition, all extracts of bastard oleaster at 5% concentrations were more effective against the nymph of mealybug than imidacloprid insecticide at 24 h. Therefore, extracts from this wild plant, bastard oleaster leaves would be promoted and used as botanical insecticide in the future.
Pumnuan, J., Sannongmueang, T., Inyod, T. and Insung, A. (2019). Effectiveness of bastard oleaster (Elaeagnus latifolia) extracts against the nymph of mealybug (Phenacoccus manihoti). Acta Hortic. 1259, 127-134
plant extract, insecticidal activity, repellent property, leaf dipping method