Insetti e globalizzazione: controllo sostenibile di specie esotiche in ecosistemi agro-forestali (GEISCA)

Biological invasion by exotic species is considered one of the main threats to the loss of biodiversity. This event is actually really common and it can cause enormous



damages in terms of socio-economic costs, harms human health, and results in ecological losses. When an exotic pest colonizes a new habitat, occupies vacant niches



and is favoured in its settlement, diffusion and to the consequent damage, at least at the beginning, by the absence of natural control agents. For this reason sometimes



it is necessary to find natural enemies in the native country, but we must also emphasize the importance of the onset of new associations between indigenous



parasitoids/predators and exotic species. Researches on natural enemies in a new environment are fundamental to start and prosecute. Pluriennial study are necessary



to evaluate the evolution of host enemies and their composition, their distribution on the territory, their efficiency and their variability in different years. Also the



evaluation of the performance of the parasitoid/predator and its adaptability to mass rearing systems needs to be taken into account for aumentative or inondative



biological control strategies. The research unit of Milan will focus the attention on three exotic asiatic species associated to plants important for their fruit production



and for their landscape-function: Dryocosmus kuriphilus (Hymenoptera: Cinipidae), Drosophila suzukii (Diptera: Drosophylidae) and Psacothea hilaris (Coleoptera:



Cerambycidae). Dryocosmus kuriphilus is one of the most important pests of plants of the genus Castanea. Detected in Italy in 2002, it is now widespread on all the



peninsula. Considering the value of natural control agent in forest ecosystems, it is important to study the parasitoid complex associated to D. kuriphilus in Lombardy,



following and synergizing the activity developed in other Italian regions and associating this study with the one of the parasitoid complex of other galligenous



cynipids in the same forest ecosystem. In fact these plants can be the source of natural parasitoids that can migrate on D. kuriphilus. Among the parasitoids particular



attention will be focused on the presence of Torimus flavipes, valuable species detected in other Italian regions.



Drosophila suzukii, is a polyphagous pest of fruit particularly noxious for its aptitude to attack fruit directly on plants and to reproduce in fruit near to maturation, for



its reproductive rate (10-13 generation/year), for the ability to spread, and for the difficulty of early damage detection. All these characteristics make chemical control



difficult, that is why it is important to investigate natural control agents, and improve the knowledge on some phases of the life cycle of the insect and on the causes of



fruit attraction (colours and volatiles) or on the role of alternative host plants.



Psacothea hilaris is a xylophagous pests of Moraceae (Ficus and Morus are preferred hosts). Detected in Lombardy in 2005 it has now settled in a small area near



Como. The unit twill focus the attention on the research of native parasitoids in field. Besides, as in 2011 a bethylid with promising characteristics was found in



association with P. hilaris larvae, the unit will prosecute the study on this species in field and laboratory with the purpose of obtaining the mass rearing of this natural



enemy. The study on the parasitoid complex of P. hilaris will furnish important information not only for the control of this pest but also for other Cerambycidae (e.g



Anoplophora, Monochamus).