Chapter 144 - Japanese Beetle

Abstract

This chapter focuses on the Japanese beetle, Popillia japonica Newman. It is among the most polyphagous of plant-feeding insects. The adults skeletonize the foliage or feed on the flowers or fruits, of nearly 300 species of wild or cultivated plants. The larvae, or grubs, develop in the soil where they feed on roots of turf and pasture grasses, vegetables, nursery seedlings, and field crops. It belongs to the family Scarabaeidae, subfamily Rutelinae. Adults are broadly oval, 8–11 mm in length, metallic green, with coppery-brown elytra that do not quite cover the end of the abdomen. The abdomen bears five patches of white hairs on both side, and another pair near its tip. Females, which tend to be slightly larger than males, have an elongate, spatula-shaped spur on the fore tibia, used for digging. This spur is shorter and pointed in males. Japanese beetles have a 1-year life cycle in most parts of their range. Adults occur from June to August. Upon emergence from the soil, virgin females emit a volatile sex pheromone that attracts clusters of males. Subsequent mating occurs on food plants. The beetles typically feed from the upper surface of leaves, chewing out the tissue between the veins and leaving a lace-like skeleton.