Good practice:

Contrast of the Japanese beetle Popillia japonica

The practice includes 3 surveillance strategies and procedures.
Firstly the detection and monitoring of larval specimens of Popillia japonica in areas that have already infested to evaluate the extent of infestation. Monitoring activities comprise field surveys in sites with high humidity, such as grassy meadows, which are known to be the ideal environment for this species to lay its eggs.
Secondly, the visual inspections of adult specimens of P. japonica during the time period when larvae transform into their adult form by a process of metamorphosis and begin to fly. These activities help to identify infested areas and to provide indications on species’ population density. Further to visual inspections, adult monitoring includes the placement of traps in infested areas to facilitate captures and gradually control established populations and likely eradicate them. Traps are equipped with a GPS system to track species’ movement.
Finally, a risk analysis and vulnerability assessment of surrounding sites currently uninfected by Popillia japonica; in this case, they include procedures to identify the sites within an infested area that are more likely to act as corridors of passive dispersal. The monitoring the sites at risks of infestation is important because high densities of adult P. japonica can represent a risk for the passive dispersion of the insect from the infested areas to uninfected areas. This can happen when the adults are accidentally transported.

Public funds. For example, in 2018, Lombardy Region allocated a budget of 330,000€ to refund the damages caused by this pest to agricolture. Moreover, in february 2020, an horizon project of 400,000 € has been financed in order to study how to contrast P. japonica.

Regional Authorities have managed to define the areas which were infested by this species. Moreover, they have produced a database and developed a code of conduct for infested areas in order to limit its dispersal, prevent new introductions, and guide appropriate management measures to control or eradicate established populations. Finally, based on risk assessment results, regional and local authorities have adopted a series of measures to minimise the likelihood of unintentional spread.

Despite the fact that up to now Popillia japonica has mainly been detected in northern Italy, evidence demonstrates a high transferability potential across Europe. Therefore, this practice provides a framework to define the geographic extent of species distribution, to assess the risk of new incursions, to prevent introduction at source, and to guide appropriate management measures. It is based on standardised procedures, easily adjustable to territorial specificities. It is generally effective for plants, animals and pests in terrestrial ecosystems. The principal objective behind the monitoring of adult specimens of Popillia japonica is to define the exact territory where the insect is present and to evaluate its natural spread, as well as to intercept populations transported accidentally into a previously uninfested area that is not adjacent to the known area of infestation. In addition, monitoring is useful in pinpointing the beginning of the period of emergence of adults.