Insecticidal effect of nanoencapsulated essential oils from Zanthoxylum rhoifolium (Rutaceae) in Bemisia tabaci populations

The purpose of this study was to develop and characterize biodegradable nanospheres containing essential oils from Zanthoxylum rhoifolium leaves and evaluate its insecticidal effect in Bemisia tabaci populations. The essential oil from 1 rhoifolium leaves exhibited an average yield of 0.03% and presented beta-elemene (31.26%), D-germacrene (18.16%), beta-caryophyllene (12.09%), delta-elemene (7.63%), beta-cedrene (6.69%), bicyclogermacrene (4.57%) and E-caryophyllene (3.63%) as main components. The PCL nanospheres containing this essential oil exhibited encapsulation efficiency higher than 96%, pH close to 5, particle diameter smaller than 500nm and zeta potential values of approximately -20 mV. The in vitro release profile was characteristic of biphasic release, i.e., a fast initial release, followed by slow release for 12h or more. The biological assay results were also significant and as such both the in natura and nanoencapsulated essential oils resulted in reductions as high as 95% in the number of eggs and nymphs compared with our control. Collectively these results suggest that both in natura and nanoencapsulated essential oils from 1 rhoifolium leaves can potentially be used in B. tabaci control in association with integrated pest management practices. (C) 2015 Elsevier B.V. All rights reserved.