Management of Popillia japonica in container-grown nursery stock in Italy

The Japanese beetle Popillia japonica is an invasive alien species recently introduced and established in Northern Italy. Adult beetles are very polyphagous and feed on vines, fruit trees, forest trees, crops, vegetables, ornamental and wild plant species. Eggs are usually laid by females in moist grassland in the summer, singly or in small clusters. Larvae feed on roots and may be transported in soil of plants for planting grown in containers. Restrictions on movement of plants grown in containers from infested to non-infested areas imposed by phytosanitary regulations have a significant economic impact on the nursery industry. An innovative approach was used to exclude beetle oviposition by weed mulching available for container-grown nursery stocks, and by testing larval survival to the application of chemical (cypermethrin) and organic (Heterorhabditis bacteriophora and Metarhizium brunneum) commercial pesticides registered for European nurseries. The high effectiveness of the method makes it a suitable component of a systems approach strategy for pest risk management, in order to achieve a safe production and trade of nursery plant material in areas infested by the Japanese beetle.