General Information

Common name: Japanese beetle
Scientific name: Popillia japonica
Coleoptera:Scarabaeidae

Synonym: Velvety chafer

Host plants

Corn, soybean, asparagus, limes, stone fruit, roses, elms, blackberry, raspberry, rhubarb (CABI, 2000)

Distribution

Japanese beetles are native to China, Japan, and Russia, but are now found in Korea, Philippines, Portugal, Canada, USA (CABI, 2000)

Damage

In corn, the beetles' feeding damage is on the maturing silk that prevents proper pollination. This results to missing seeds in the corn ear (CABI, 2000).

On soybean, beetles feed on leaves and flowers. They chew the leaf tissues in between the veins leaving only the veins. Their feedings make the leaf veins a lacelike skeleton. Leaves that are heavily damaged will turn brown, wilt, and finally drop (CABI, 2000).

The adults feed in groups usually starting at the top of the plant then moving downwards (CABI, 2000).

Description

The eggs are white, small (about 1.5 mm), and oblong when newly laid. These are laid in moist soil at a depth of 7.5 cm, either singly or in a batch of 4. The eggs absorb water from the soil, become spherical, and double in size within a week. The developing embryos are visible within the eggs when they are about to hatch. The eggs hatch after 2 weeks.

The larva is called the white grub with a V-shaped series of stiff hairs on the snout. It has yellowish-brown head with strong mandibles. The body has 3 segments, each segment having a pair of jointed legs. It is usually in a C-shaped position when found in the soil. Newly hatched larva is about 1.5 mm long and reaches 3.2 cm long when fully matured. Upon hatching, the larva starts feeding on the fine roots and organic matters in the soil.

The fresh pupa is creamy, turns reddish-brown, and finally becomes metallic-green when it reaches maturity. It looks like the adult but the wings and other appendages are closely folded to the body.

The adult is broadly ovate-shaped with shiny metallic-green color body and dark-copper green legs. The wings' covers are copper-brown. Its abdomen is colored green with white patches and has a row of five tufts of white hairs on each side. The white patches on the green abdomen distinguish Japanese beetles from all other beetles.

The newly emerging adult beetle (from the ground) immediately looks for food, then releases an odor as a signal to other emerging adults where it can be located. This will result to a group of adults meeting and feeding on a single host plant.