The use of semiochemicals in the olive grove: An essential tool

Abstract: Semiochemicals are natural products involved in chemical communication between living organisms. In an initial classification, semiochemicals are subdivided into pheromones and allelochemicals depending on whether the interactions are intraspecific or interspecific, respectively. Pheromones are released by one member of a species to cause a specific behavior to another member of the same species. This chemical language of insects has been the subject of deep research in the field of chemical ecology for the past fifty years. Pheromones are classified based on the interaction mediated, such as sexual attraction, alarm, recognition, aggregation, and many others. Insect sex pheromones have been most widely applied in integrated pest management (IPM) but other behavior-modifying semiochemicals have had success from a commercial point of view too. In many cases, pheromone-based methods have been successful; however, after years of applied research, it has become clear, that the development of semiochemical-based strategies for controlling insect pests was harder than we thought. There are many factors such as the ethology, the population of the target insect, the technical development of the active compound, or economic reasons, which determine the success/failure of its final application. Usually, the complete research work takes five to ten years.
In order to prevent the excessive use of synthetic insecticides in olive groves causes food residues, environment pollution, insect resistance problems or secondary pest resurgence, during the last three decades, pheromones and other semiochemicals are usually used in olive groves Integrated Pest Management programs. Following the identification of the sex pheromone of the olive pest (Prays oleae) in 1979 and, in 1980 the female sex pheromone of B. oleae, expectations for its potential use in IPM programs and sustainable agriculture were huge. The most widespread use of pheromones in olive groves has been for monitoring adult insect pest populations, so until now, the main uses of semiochemicals in olive groves IPM are monitoring and attractant-kill techniques. Even though mating disruption is probably, the semiochemical-based technique most successfully used in IPM, in our crop is still under development and not fully implemented.
Many factors such as the ethology or population of the target insect, the technical development of the active compound or economic motives determine the success or failure of its application. What are we missing to obtain better results with the use of semiochemicals in olive orchards? What new challenges do we face?
There are many questions to answer and to illustrate these issues; examples of successes and failures in the application of semiochemicals in olive groves will be briefly described.