Japanese and false Japanese beetles: The Japanese beetle, Popillia japonica, [top] and sand chafer or false Japanese beetle, Strigoderma arboricola [bottom]. Although the two beetles look similar, the Japanese beetle has a metalic green head and thorax whereas the sand chafer has a black and orange head and pronotum. The Japanese beetle may cause substantial defoliation in small areas of a soybean field, whereas the sand chafer is not known to cause economic damage to soybean. (Photos Marlin E. Rice)
The eggs of the Japanese beetle, Popillia japonica, are 0.5-0.8 inches (1-2 mm) around and white in color. They are deposited in the soil. Once the eggs hatch the larvae will remain in the soil to feed on plant roots. The larvae are typical white, C-shaped gubs that are 0.5 - 1.2 inches (1.5 - 32 mm) long depending on the instar.
The adult Japanese beetle has a bright metalic green head and thorax with white markings on its abdomen. But don't confuse it with the false Japanese beetle, Strigoderma arboricola (see photo).