István Ujváry
Plant Protection Institute, Hungarian Academy of Sciences, P. O. Box 102,
Budapest, H-1033, Hungary
After four decades of research and development, the use of semiochemicals in the abatement of insects of agricultural and medical importance seems to be firmly established. However, enthusiastic expectations about the direct application of these selective substances in pest control have not been fulfilled. The economical and effective use of the mating disruption technique, already proposed in the early sixties-1,2, is more of an exception than a rule. Clearly, the practical potential of these natural compounds is limited by factors inherent in the biological system itself that relies on these chemicals. The perception and catabolism of these volatile compounds are finely tuned and fairly rapid biochemical and physiological processes- have specifically evolved to aid host and mate seeking behaviour.
An obvious solution to this problem is the design of metabolically stable, active analogues. These compounds, however, should not only be cost-effective but safe if they are to be developed for large scale use as pest control chemicals. From a toxicological point of view no presumption of innocence is applicable to chemicals used ln a similar manner as conventional insecticides.
It should also be realised that semiochemicals are not to replace but to complement our present armory of chemical and biological insecticides. These compounds, acting on specific and novel targets, should be regarded as lead compounds that are amenable to further chemical modifications the potential of which has not been fully exploited yet.
This paper, using primarily data from our research of the past 15 years, will illustrate some failures and successes for selected case studies in this field. Emphasis will be put on "bioisosterism" that often provided ideas for structure-based analogue design. Results of studies with analogues of the following semiochemicals will be presented: sex pheromones of the European grapevine moth (Lobesia botrana), the cabbage moth (Mamestra brassicae), and the cranberry girdler (Chrysoteuchia topiaria); kairomones such as host odour components for tsetse flies (Glossina species) and floral volatiles for the western com rootworm (Diabrotica virgifera virgifera).
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