Effects of vetiver oil and nootkatone on Myzus persicae infesting eggplants in a controlled environment

The essential oil of vetiver (Vetiveria zizanioides (L.) Nash.) and the sesquiterpenoid nootkatone, commonly used in the perfume and flavour industries, were reported to show repellent, feeding deterrent and toxic effects to Coptotermes formosanus Shiraki, one of major pests of structural wood. The present investigation aimed to study the effects of the two substances on a serious pest of agricultural systems, the green peach aphid Myzus persicae (Sulzer), which was maintained in a controlled environment on eggplants (Solanum melongena L.), representing one of its most important herbaceous hosts. Preliminary tests were performed to verify the phytotoxicity of formulations of the two substances, using fluorescence microscopy. The activity on M. persicae was tested by means of different experiments: a) using foliar disks, and, b) spraying the plants before and after aphid colonization. Evaluations of aphid behaviour and observations on the number of colonizing individuals and of nymphs generated parthenogenetically were performed. The results suggest that, in spite of the problems emerged with the used formulations, both substances could represent potentially good candidates as active ingredients for the control of this aphid.