Applied pheromone research

The synthesis of pheromones remains an important cornerstone of pheromone research and development. The initial synthesis of an insect pheromone serves not only to confirm the structural identification, but also provides authentic material for either laboratory or field bioassay. Oftentimes, larger quantities of the pheromones are desired for the development of monitoring and pest control methods. The scale up of the synthesis of complex pheromone compounds is often a major bottleneck in the practical application of pheromones. Also, the unusual structure of some pheromone compounds beckons synthetic chemists to apply new methodology in order to show off their methods. 

Pheromones, especially insect pheromones, have become common news stories in the popular press and hence are well known to most people. For instance, most elementary schools in the USA now include coverage of pheromones in general science and biology courses. Concomitant with this widespread coverage and inclusion in elementary school curricula is ongoing basic and applied research, which leads to important practical uses and beneficial applications. Since Butenandt s initial report on the pheromone of the silk worm moth, there have been many reviews of pheromones and recent ones are cited here. This review of the chemistry of insect pheromones will cover the isolation and identification of new pheromones and the synthesis of these compounds as well as other recently reported syntheses of important pheromones. 

Field measurements of concentrations of disparlure in air under woodland plots treated with three different slow release formulations showed that all released pheromone for about one month concentrations decreased about 80 in the first five days and 90-98 over 35 days. Between 75 and 85 of the disparlure remained in the formulations after 35 days even though release had became very slow. Measurements with other formulations containing tetradecenol formate applied to corn showed these were more efficient but not persistent enough to control Heliothis Zea for more than one month. No satisfactory measurements of concentrations in vapor plumes from point sources were possible even though these may be as effective as broadcasts. Further field research is limited by sampling and analysis techniques and the need for better micrometeorological data. 

Pheromones used in social insect communication are usually highly volatile, and their chemistry can be analysed using gas chromatography and mass spectroscopy. This can often yield useful pointers regarding their function. Among different lines of research, morphological research is applied to study the detailed structure of the reproductive system. 

Fig. 24.5 Field investigation of the sea lamprey sex pheromone to develop management application. (a) Researchers measure sea lamprey pheromones for a field trial, (b) A fluorescent dye (asterisk) is applied to measure a pheromone plume in the stream, (c) An ovulatory female sea lamprey is attracted to the source of the male pheromone (double asterisk tube opening hidden under the rocks), (d) Traps baited with sea lamprey pheromones (photos provided by Dr. Nicholas S.Johnson)...

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