Potential for the use of semiochemicals against Locusta migratoria migratorioides (R. & F.)

Abstract

Summary Pheromones, both of the primer and releaser type, have been detected in Locusta migratoria. Research is in progress aiming at the identification and future synthesis of scmiochemicals that might find application in programmes of integrated management for this pest. In laboratory experiments, the oviposition rhythm and fecundity of virgin females were to some extent stimulated by the proximity of males. Chromatographic and mass spectrometric (MS) analysis of the semiochemicals of L. migratoria migratorioides were performed, and important variations in the composition of the bouquet of odours emitted by different stages, and sexes, were detected. Thus benzyl cyanide was only produced by sexually mature males, while by contrast, guaiacol was detected in nymphs and adults of both sexes, although females contained larger amounts. Different strategies, based on the use of semiochemicals, can be devised, aiming at the control and particularly the monitoring of populations of the migratory locust. Among them, the application of aggregation/arrestant pheromones to concentrate egg laying in pre-selected sites, where the eggs would afterwards be destroyed, preferably by bio-pesticides, should be considered. The use of maturation synchronisers could also be taken into account, to time adult development with unfavourable climatic periods. However, the implementation of methods resorting to the application of pheromones must be contemplated in combination with other techniques, such as cultural practices, within the scope of an encompassing Integrated Pest Management (IPM) programme.