Popillia japonica – Italian outbreak management

Abstract

Popillia japonica, a priority pest for the EU, was first detected in Northern Italy in 2014. Since its discovery, the outbreak extended over an area of more than 16,000 square kilometers in Northern Italy and Southern Switzerland. In this review, we summarize the state-of-the-art of research conducted in Italy on both the spreading capacity and control measures of P. japonica. Chemical, physical, and biological control measures deployed since its detection are presented, by highlighting their strengths and weaknesses. An in-depth study of the ecosystems invaded by P. japonica disclosed the presence and pathogenicity of natural strains of entomopathogenic fungi and nematodes, some of which have shown to be particularly aggressive towards the larvae of this pest under laboratory conditions. The Plant Health authorities of the Lombardy and Piedmont regions, with the support of several research institutions, played a crucial role in the initial eradication attempt and subsequently in containing the spread of P. japonica. Control measures were performed in the infested area to suppress adult populations of P. japonica by installing several traps (e.g., for mass trapping, for auto-dissemination of the fungus Metarhizium anisopliae, and “attract & kill”). For larval control, the infested fields were treated with commercial strains of the entomopathogenic fungus M. anisopliae and nematode Heterorhabditis bacteriophora. Future studies will aim at integrating phenological and spread models developed with the most effective control measures, within an ecologically sustainable approach.

Biocontrol potential of six Heterorhabditis bacteriophora strains isolated in the Azores Archipelago

“…The Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae), stands as a major insect pest native to Japan that reached mainland Europe in 2014 causing great damage in the Italian region (Glazer et al 2022; Gotta et al 2023). The larval stage exerts detrimental effects on grasslands and pastures, whereas adults feed on the foliage of agricultural crops and ornamental plants (Potter and Held 2002).…”

Predicting the spatio-temporal dynamics of Popillia japonica populations

“…The species most likely established in that area a few years before 2014, and at the time of the first detection it was already in a spreading phase. Currently, the species has been able to invade more than 16000 km 2 of territory, covering vast areas in Lombardy and Piedmont and reaching some municipalities in northwest Emilia Romagna and in Valle d'Aosta (EPPO, 2022b;Gotta et al, 2023;Europhyt Outbreak No. 574, Update 07/2022-12-05).…”

“…Despite the availability of detailed information on the pest biology and ecology, to the best of our knowledge a quantitative description of the pattern of temporal population dynamics and the estimation of the intrinsic population growth rate are highly limited in literature. Preliminary results obtained by the GESPO project (funded by Lombardy Region, https://sites.google.com/unibs.it/gespo-project-en) analysing the ongoing spread of P. japonica in Lombardy have led to the identification of a clear logistic growth pattern (Gotta et al, 2023;Sperandio et al, submitted).…”