Phormium mealybug

Like the host plant, phormium mealybug originates from New Zealand and is able to survive British winters out of doors. Most other mealybugs found in Britain which are dependent on glasshouse conditions. Mealybugs suck sap from plants and excrete the 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.

Phormium mealybug is specific to Phormium and can prove damaging, particularly on young plants. The insects tend to cluster around the base of the leaves and heavy infestations cause plants to lack vigour and the foliage may die prematurely. Older established plants seem to be more tolerant of this insect and will often survive without much obvious damage.

This is a very difficult insect to control as the mealybugs are concealed at the base of leaves or where leaf margins are folded together. This makes it very difficult to reach them with a pesticide and none of the products currently available to home gardeners is likely to give effective control.

• Established plants can tolerate light infestations of Phormium mealybug
• When purchasing a Phormium examine it carefully and reject any that shows signs of mealybug infestation. A plant free of mealybug is likely to remain in that condition as this insect cannot fly and there is little opportunity for it to spread from other gardens
• Consider replacing heavily infested plants
• The biological controls for available for glasshouse mealybugs are unlikely to control phormium mealybug as they require the warmer temperatures in glasshouses to be effective

Mealybugs
Golden root mealybug
Sooty moulds