Japanese Beetle

Behavior

The life cycle of the Japanese beetle is typically one year in most parts of the United States, but this can be extended in cooler climates; for instance, in its native Japan, the beetle's life cycle is two years long as a result of the higher latitudes of the grasslands required for the larval stage. During the larval stage, the white grubs can be identified by their V-shaped raster pattern.

Food

It is not very destructive in Japan, where it is controlled by natural predators, but in North America it is a serious pest of about 200 species of plants, including rose bushes, grapes, hops, canna, crape myrtles, birch trees, linden trees and others.

Evolution

As the name suggests, the Japanese beetle is native to Japan. The insect was first found in the United States in 1916 in a nursery near Riverton, New Jersey. It is thought the beetle larvae entered the United States in a shipment of iris bulbs prior to 1912, when inspections of commodities entering the country began. "The first Japanese beetle found in Canada was in a tourist's car at Yarmouth, arriving in Nova Scotia by ferry from Maine in 1939. During the same year, three additional adults were captured at Yarmouth and three at Lacolle in southern Quebec."

Cultural

It is a clumsy flier, dropping several centimeters when it hits a wall. Japanese beetle traps therefore consist of a pair of crossed walls with a bag or plastic container underneath, and are baited with floral scent, pheromone, or both. However, studies conducted at the University of Kentucky and Eastern Illinois University suggest beetles attracted to traps frequently do not end up in the traps, but alight on plants in the vicinity, thus causing more damage along the flight path of the beetles and near the trap than may have occurred if the trap were not present.

These insects damage plants by skeletonizing the foliage, that is, consuming only the leaf material between the veins, and may also feed on fruit on the plants if present.