Phenology and life table parameters of the brown marmorated stink bug in Northern Italy

The Asian brown marmorated stink bug (BMSB) Halyomorpha halys (Heteroptera, Pentatomidae) is an highly invasive species with a broad host range, including fruit trees, vegetables, ornamental and wild species. In the United States, where it has been accidentally introduced nearly two decades ago, it has 1-2 generations per year and is considered as one of the major agricultural pests, causing several million dollars losses, especially in orchards. In Switzerland, where it has been present since 2004, it has only one generation and is mainly a dwelling nuisance. In 2012, BMSB was first detected in Emilia Romagna (Italy), one of the most important fruit producing regions in Europe. It is currently spreading all over Northern Italy and rapidly dispersing throughout the rest of the country. In 2015, high BMSB populations were reported in pear orchards, causing severe damage of sometimes 80-100% deformed fruits in the orchard borders. To investigate the phenology of BMSB under outdoor conditions in Northern Italy, field collected adults were overwintered outside in boxes sheltered from precipitation. In spring overwintering mortality and the emergence of adults from their overwintering sites were assessed. Survived adults were then paired and fecundity and development time of eggs and nymphs were recorded throughout the season. BMSB overwintering survival was over 20%, with adults exiting their overwintering sites from March to May. In northern Italy, BMSB has two overlapping generations per year, with important differences in longevity and fecundity. The obtained parameters show the high invasive potential of BMSB, eliciting serious concern for many Italian crop productions. These data are indispensable for the development of models to forecast pest outbreaks in the future.