In a recent review paper on neem and other botanical
insecticides, three barriers to the commercialization of
new products of this type were identi"ed: (i) the scarcity
of the natural resource; (ii) the need for chemical standardization
and quality control; and (iii) di$culties in
registration. As the essential oils and their puri"ed constituents
have a long history of global use by the food and
fragrance industries, and most recently in the "eld of
aromatherapy, many of the oils and/or constituents that
are pesticidal are readily available at low to moderate
cost in quantity (USD 7}30 kg~1). A number of constituents
are available commercially in reasonable purity
(95%), and essential oil producers and suppliers can often
provide chemical speci"cations for even the most complex
oils.