Bondi Junction NSW, Australia
Fact Sheets
Yam scale (093)
Pacific Pests, Pathogens and Weeds
Pacific Pests, Pathogens and Weeds


  • Widespread distribution. West Africa, India, Oceania. On yams, ginger, taro and turmeric are minor hosts. Occasionally, an important disease.
  • The scale (1-2 mm diameter) causes a problem in storage. It has long tube-like mouthparts to suck the sap from yams, which then become fibrous. It is covered by a protective shell, called the 'armour'.
  • Eggs hatch as 'crawlers'. They walk or are blown in the wind. Both sexes settle down, feed and produce the armour, but males become winged, tiny, mosquito-like insects without mouthparts that mate and then die.
  • Cultural control: check each yam tuber before storage, and discard (eat) those with yam scales.
  • Chemical control: if scales seen at harvest or during checks in storage, treat with soap, white or horticultural oils with or without malathion.

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