Japanese beetle

The Japanese beetle (Popillia japonica) is oval and slightly smaller than a 5-cent coin: it is about 8-12 mm long and 5-7 mm wide. Unlike the native beetles (Melolontha melolontha, Mimela junii and Phyllopertha horticola), with which it can be easily confused, the Japanese beetle has five white hairy tufts on each side of the rib and two larger white hairy tufts on the bottom of the back. The head and pronotum (upper part of the thorax) are metallic green or pink, while the elytra are copper-colored. It spreads rapidly between June and September.

It is dangerous because it is very voracious and invasive to vegetation and agriculture. It infests more than 100 types of plants, both cultivated and wild; thus, it attacks crops (grapevine, corn, soybean...), lawns, private gardens, pastures, forests, wild plants, fruit plants (pear, cherry, peach, plum...), including small fruits (raspberry, strawberry, blackberry, currant, giant American blueberry...), and ornamental plants, for example, roses. Harmless to humans, it is, however, responsible for serious economic damage, both in the larval and adult stages. Present in southern Ticino, there is a risk of its further spread.

What to do in case of a sighting

Citizens' cooperation is essential to counter the spread of the Japanese beetle by monitoring their own land, gardens and vegetable gardens.

If it is found, it should be captured, placed in a closed jar and immediately call the Cantonal Plant Protection Service at +41 91 814 35 85. Every report is valuable, even if in doubt or in the case of larvae. Anyone who suspects that they have found adult Japanese beetles or larvae is obliged to report it, as is also reiterated in the Cantonal Decision concerning it. It is easier to catch the Japanese beetle in the morning on plant foliage because it is less active than during the warmer hours of the day when it is in flight.

In general, it is important to be careful not to unintentionally carry adult Japanese beetles, which swarm in large numbers during the flight period and can get into the passenger compartments of cars or trucks, as well as in luggage and walking bags.

More information on the Japanese beetle can be found on the Cantonal Plant Protection Service website:

Cantonal Plant Protection Service