Vapours of essential oils, extracted from 12 Mediterranean plants of the families Lamiaceae, Verbenaceae and Apiaceae, were assayed for insecticide activity against the aphid pests Acyrthosiphon pisum (Harris) and Myzus persicae (Sulzer). Different doses were applied, starting from 2 ml/l air and halving the dose until no activity was registered. Anise, fennel and basil essential oils resulted in high mortality, even applied at low doses. Activity was dose-dependent. The occurrence of phytotoxicity following the application of some essential oil is discussed. In spite of the well-known drawbacks owing to phytotoxicity, the application of essential oils in the control of pests on plants appears feasible.

The tree-of-heaven, Ailanthus altissima Swingle(Simaroubaceae), was studied for its potential insecticide activity against the pea aphid, Acyrtosiphon pisum (Harris). First instar aphids were dipped in water solutions of root extract and of leaf extract of A. altissima, and this was followed by bioassay-oriented fractioning of leaf extract (more active in bioassays) with petroleum ether, chloroform, chloroform-methanol, methanol and water, and of chromatographic fractions. The putative active constituent ailanthone, isolated from the plant resulting in the highest aphid mortality, has been assayed as a pure compound in different concentrations, proving to be responsible, for the insecticidal activity reported