Cabbage Leaf Beetle

Cabbage Leaf Beetle
 Order: Coleoptera (Beetles)
 Family: Chrysomelidae (Leaf Beetles)

▶Scientific name: Chrysolina aurichalcea (Mannerheim)
▶Size: 7-10 mm in body length
▶Host plants: Mugwort (Artemisia spp.), 
  Chrysanthemum, wormwood, and other Asteraceae plants
▶Distribution: Korea, Japan, China, Taiwan, Mongolia, 
  eastern Siberia, Sakhalin Island, etc.

The beetle measures about 7-10 mm. Its body color is metallic black-bronze or bluish-green with a shiny luster. The vertex has a few irregular punctures and slightly depressed areas. The antennae are black, with the basal two segments partially reddish-brown. The elytra (hardened forewings) are covered with dense punctures and show distinct longitudinal striations.

Larvae appear from April after overwintering and feed on the young leaves of mugwort until early May. During summer, the population density decreases sharply as they enter summer dormancy. Numbers increase again in September when both leaves and flowers are consumed. Reproduction occurs in October to early November. Adults feed on the young leaves of Asteraceae plants from spring to fall, with peak activity in May-June. When disturbed, they readily drop to the ground and exhibit thanatosis (feigning death).
 [Source: Korea National Arboretum]