An integrated pest management approach for the Mellieħa region : with emphasis on the influence of three species of Coleoptera on specific host trees

Abstract

The Maltese Islands, being situated on the Siculo-Maltese sill in the central part of the Mediterranean, are no exception to colonization by alien species of insects. Theintroduction of alien beetles both accidentally and via deliberate means into the MalteseIslands have endangered biodiversity and increased economic costs due to measures taken to control these species from invasion. Favourable climate conditions and the availability of host trees in the local environment has allowed the Rhynchophorus ferrugineus, Hypocryphalus scabricollis and Phryneta leprosa to establish, flourish and increase their population. Since their introduction these Coleoptera species have caused severe damage and killed a significant amount of host trees. The present study identifiedand located infested and healthy host trees: Phoenix canariensis, Phoenix dactylifera, Washingtonia spp., Ficus carica, Morus nigra and Morus alba by field surveys within the Mellieħa region to create vulnerability maps on Geographic Information Systems software to detect the probability of these host trees from being infested in the future. Initial indications show that these Coleoptera species have established in the Mellieħa region and have already caused severe damage to host trees. Further analysis regarding the flight distance of these Coleoptera species and their ability to disperse acting upon the wind direction revealed that a significant amount of host trees show vulnerability to being attacked by these wood-boring in the near future. The study concluded that if the infestation within the Mellieħa region should continue then these host trees are facing a major threat leading to mortality. Suggestions include the implementation of an integrated pest management strategy to reduce the further spread of these Coleoptera species in the Maltese Islands and prevent economic losses to local farmers and hotel owners.