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Botanical pesticides: optimizing
pest control and minimizing
environmental impacts
B.J.R. Philogène1 and J.D.H. Lam bert2
of Ottawa and 2Department of Biology, Carleton University,
Ottawa, Ontario, Canada
Various types of botanical pesticides and their mode of action are examined:
photosensitizers, antifeedants, and lignans. The role of naturally
occurring synergists is also discussed. For any new botanical substance
to be accepted as a safe biocide, it must be subjected to the same rigorous
toxicity tests as synthetic products. The steps in this process are identified
and outlined, using the molluscicide endod as an example.
The use of chemicals of plant origin for the control of destructive insects or
vectors of diseases is not new. Rotenone, nicotine, and pyrethrins have been
available for a long time (Matsumura 1975). Only pyrethrins remain in use as
efficient, low-cost insecticides.
With increasing problems of toxicity and resistance of target pests to the
synthetic compounds currently in use, interest in "natural" pesticides has
revived. Pest-management specialists have been looking elsewhere for pest
control as a result of the environmental and health problems brought about
by the intensive and extensive use of organochlorines, organophosphates, and
carbamates. Moreover, third-generation insecticides (insect hormones and
their analogues) have not produced the results expected.
Botanical pest control attempts to provide environmentally acceptable methods
of insect control through the naturally occurring substances in the crop
plant or application of compounds derived from other plants. Such compounds
and their derivatives should minimize losses at all the stages of
agricultural and forest production and provide new molecules for the control
of disease vectors. The search for new chemicals to be used as insecticides may
also provide compounds with a mode of action different from the classic
neurotoxicant, against which so many arthropod species have become resistant.
This important development in pest-management strategies has been
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