ABSTRACT
The ease with which essential oils are obtained from aromatic plants and their diverse chemical compositions makes them potential sources of natural pesticides – either through direct toxicity or by repellency – and they have attracted increasing attention among researchers (as reviewed, for example, by Singh and Upadhyay 1993). As natural repellents they have seen a resurgence of interest since the use of synthetic compounds began to displace the large number of essential oils which were formerly used in the 1930s and 1940s (Curtis et al. 1990). Their volatility has potential benefits in terms of bringing the pesticide vapour into close contact with the pest while at the same time not leaving residues which might adversely affect the object being protected, be this a crop or food product, or, in the case of, for example, a mosquito repellent, the human body. With the ever-increasing level of air travel the danger of catching malaria and other mosquitoborne diseases is now a worldwide one and not confined to people living in the tropics.
