What is phormium mealybug?
Phormium mealybug is only found on Phormium and like the host plant originates from New Zealand, it is able to survive British winters out of doors. Most other mealybugs found in Britain are dependent on glasshouse conditions. Mealybugs are sap sucking true bugs. They excrete excess sugars as honeydew this lands on the leaves and stems were it is often colonised by sooty moulds, giving the surfaces a blackened appearance.
The mealybugs tend to cluster around the base of leaves. On young plants large populations can cause plants to lack vigour and foliage may die prematurely. Older established plants seem to be more tolerant of this insect and will often survive without obvious damage.