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Katydid

Date: 14 Aug 2002   Author: Jianhua Mo

Three species of katydids are found in the Riverina area, causing minor to occasionally important problems for citrus growers.

Description

  • Grasshopper-like insects with thin, long antennae (usually longer than body).
  • There are three species of katydid in Australia:
    • citrus katydid
    • inland katydid
    • spotted katydid.
  • Adults are green to brown, and 40–50 mm long.
  • There is one generation per year.
  • Eggs are laid from January to April.
  • Nymphs hatch in early spring and develop through five stages.
  • Adult stage is reached during December–January.

Damage

Katydid

  • Nymphs and adults feed on citrus flowers, fruits and leaves.
  • Feeding on fruits results in fruit drop or deep chalk-like scars on the fruit surface (see image).
  • Damage is more common in oranges than in lemons, grapefruit or mandarins.

Natural enemies

  • Parasites: an unidentified tachinid fly species, and an unidentified wasp species.
  • Predators: assassin bug, praying mantises, sphecid wasps, and birds.

Monitoring

  • Monitor every 2 weeks from mid-September to late November.
  • On each occasion, check five randomly selected fruits from each of five randomly selected trees.
  • Use sticky trunk bands to monitor the numbers of emerging nymphs.

Control measures

  • Action should be taken when 5% or more fruits are showing fresh injury, or when sticky bands have more than two emerging nymphs per tree.
  • Use a selective insecticide in areas of the orchard where the action threshold is exceeded.

More information