Leaf beetles

Leaf beetles (Chrysomelid leaf beetles) include eucalyptus tortoise beetles (Paropsis), northern eucalyptus leaf beetles (Paropsisterna) and their relatives.

Larvae feeding on foliage can defoliate trees and repeated defoliation can negatively impact tree growth.

In south-eastern Queensland and northern New South Wales, up to 4 generations a year cause at least 3 peaks in defoliation.

Scientific name

Paropsis atomaria, Paropsisterna cloelia

Description

  • Adult leaf beetles may look like ladybird beetles, but with longer antennae; distinguishing between the 2 is important because ladybirds are beneficial insects.
  • Length ranges from about 4–15mm.
  • Colours can be metallic, pink, yellow, beige or red.
  • Adults may have finely patterned elytra (wing covers); some of these are strongly patterned with red and black.
  • Larvae have well developed dark heads and 3 pairs of legs, most are pale, some with dark stripes along the body.
  • Larvae feed on the soft, young growth in the crowns, giving a typical 'broom top' appearance.
  • Scalloped leaf edges indicate adult leaf beetles feeding.

Distribution

Eucalyptus tortoise beetle (Paropsis atomaria)

  • Common and widely distributed throughout south-eastern Queensland and south-eastern Australia.

Eucalyptus leaf beetle (Paropsisterna cloelia)

  • Found in south-eastern and northern Queensland.

Hosts

  • Affects trees less than 3 years old.
  • Susceptible to eucalyptus tortoise beetle (Paropsis atomaria):
    • Gympie messmate (Eucalyptus cloeziana)
    • blackbutt (E. pilularis)
    • spotted gum (Corymbia citriodora)
    • Dunn's white gum (E. dunnii).
  • Susceptible to eucalyptus leaf beetle (Paropsisterna cloelia):
    • rose gum and hybrids (Eucalyptus grandis)
    • Dunn's white gum (E. dunnii).

Damage

  • Defoliation by clusters of feeding larvae.
  • Trees typically develop a 'broom top' appearance.
  • Repeated, widespread defoliation affects growth.
  • High densities of larvae can stop the central tree stem growing more strongly than side stems (apical dominance) so 'bushing' may occur in the crown (top part of the tree).
  • Scalloped leaf edges identify damage caused by adults feeding.

Resources and research