Notes on Elodia morio (Fallén) and other tachinide reared from field-collected Lepidoptera in Emilia Romagna, northern Italy

The codling moth Cydia pomonella (L.) (Tortricidae) is worldwide recognised as the insect key-pest of apple, pear and walnut orchards (Barnes, 1991). In the last two decades, in Emilia Romagna (northern Italy) Integrated Pest Management has been applied to control this species and, in recent years, both biotechnical (mating disruption) and microbial (CpGV) methods have been increasingly utilised (Galassi et al., 2001). In this framework, the role of natural antagonists, which has till now been considered of minor interest for the codling moth control, could be revalued. In 17 locations distributed in the provinces of Modena, Bologna and Ferrara (Emilia Romagna, north-east Italy), a study was carried out from 2003 to 2005, with the aim to verify the occurrence of codling moth parasitoids on the major plant hosts (Pyrus communis L., Malus spp.and Juglans regia L.) and in agroecosystems characterized by different ecological complexities and pest management. For this area, no recent record of C. pomonella parasitoids was found in the literature. Some specimens of Hymenoptera Ichneumonidae, Braconidae and Chalcididae were however obtained from C. pomonella in the province of Bologna, in the years between 1930 and 1936, and in the province of Ravenna (Romagna, north-east Italy), in the years between 1954 and 1957. These specimens are kept in the entomological collections of the Departments of Agroenvironmental Sciences and Technology of the University of Bologna and of Animal Biology of the University of Modena and Reggio Emilia. In the present study C. pomonella larvae were collected using cardboard stripes which were placed around the trunks of plant hosts in August and removed in full winter. In the laboratory, the live larvae were placed in corrugated cardboard cylinders inside PVC jars with a hole on the lid. Glass jars were put over the holes to collect the newly-emerged moths and parasitoids. From 2003 to 2005 more than 12000 larvae were collected and reared in order to monitor parasitoid emergence. Observations were also performed on other Lepidoptera, mainly Tortricidae, which shared plant hosts with C. pomonella or were particularly abundant in the investigated agroecosystems. On pear, apple and walnut trees, the same cardboard stripes used for C. pomonella larvae were utilized to collect larvae of the quince moth Euzophera bigella (Zeller)(Pyralidae), while buds infested by Tortrix viridana (L.) larvae (Tortricidae) were collected from oaks, in particular Quercus pubescens Willd. Finally, in order to complete the observations started before 2003, larvae of the leafroller moths Archips podanus (Scopoli), Pandemis cerasana (Hübner) and Argyrotaenia ljungiana (Thunberg) [= pulchellana (Haworth)] (Tortricidae) were mass collected from apple and pear orchards. In the laboratory, from the field-collected larvae a number of parasitoids emerged, including tachinids which were kindly determined by Hans-Peter Tschorsnig of the Staatliches Museum fur Naturkunde, Stuttgart, Germany. All the tachinids emerged from C. pomonella belonged to the species Elodia morio (Fallen) [= tragica (Meigen)] which was also obtained from T. viridana. Both moths were reported as natural hosts of E. morio by Kara & Tschorsnig (2003). E. morio is reported as one of the most important parasitoids of the codling moth in continental Europe (Rosenberg, 1934; Attanassow et al., 1997; Coutin, 1974). In recent investigations conducted in north-west Italy this tachinid was however not found (Re et al., 1998; Alma, 2006, personal communication). In the present study (conducted in north-east Italy) E. morio was only obtained from larvae collected in complex agroecosystems of the hill land. In these environments, the percentages of successfully parasitized C. pomonella larvae ranged from 2.5% to 7.4%. In his field- study carried out in Romagna (north-east Italy) using an entomological net, Campadelli (1989) also collected E. morio adults in ...