Spread of the ragweed leaf beetle, Ophraella communa LeSage, 1986 (Coleoptera Chrysomelidae), in Piedmont Region (northwestern Italy)

Common ragweed, Ambrosia artemisiifolia L., one of the most dangerous invasive species for its high allergenic pollen production, has been spreading in Europe since the 19th century but has not until now recruited any effective natural enemy. In its native range, North america, many insects and fungi are recorded feeding or developing on this weed, reducing common ragweed impact on human health and habitats. Some of these organisms, specific or oligophagous on A. artemisiifolia, are considered promising agents for the biological control of this weed, and in some cases they have already been introduced in other continents. Among these species, the leaf beetle Ophraella communa LeSage (Coleoptera: Chrysomelidae) was found at the beginning of august 2013 attacking common ragweed near a nursery in Galliate (Novara province - piedmont Region). Field surveys were carried out from august to November in various piedmont counties to document the spread of this recently introduced galerucine species. Data are reported regarding the leaf beetle’s morphology, biological cycle, spread, hosts and natural enemies in the new range. Prospects for the biological control of common ragweed in Europe are also discussed.