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.