Japanese beetle captures decline in Ticino

The number of Japanese beetles captured in Ticino is currently falling sharply. The Department of Finance and the Economy reports this based on the monitoring still under way in the infested area. A final assessment will only be possible at the end of the season.

The cantonal strategy to contain Popillia japonica has been implemented with the involvement of the municipalities. The system includes 3,400 pheromone traps for intensive monitoring. A total of 71 municipalities have joined the effort. They are also responsible for managing and regularly emptying the traps.

According to the data available on 27 July, around 25 million insects have been captured. The final count will be completed once data from all municipalities have been received. The results will help identify areas with a higher presence of the beetle. They will also help determine where to strengthen measures.

The situation in the area

The Japanese beetle is a quarantine pest originating in Asia. It was detected in Ticino in 2017. Since it has become established in the area, eradication is not considered possible. The Federal Office for Agriculture has therefore defined an infested area and a buffer zone. Measures are applied there to limit its spread.

Stable spring conditions and high temperatures favoured the synchronised development of the larvae in the soil. Adults appeared in a concentrated manner between the end of June and the beginning of July. This development made it possible to concentrate agricultural measures over a shorter period.

In 2026, the insect became established on the Magadino Plain, in the Locarno area, in the Bellinzona area and in some wine-growing areas of the upper valleys. Severe defoliation was observed in some vineyards. It is not yet possible to determine whether this will affect production. The affected plants are meanwhile showing good vegetative recovery.

The PUPILLA research project is also under way on the Magadino Plain. It is being conducted by WSL and Agroscope-Campus in Cadenazzo. To allow the project to proceed, the Federal Office for Agriculture exempted the municipalities in the study area from installing the network of traps that had initially been planned.

The next update is expected in the first half of October.