The New Zealand Flax (Phorium sp.)Mealybug (Balanococcus diminutus) is a small soft bodied insect that
inhabits the tight confines of the leaf base of New Zealand Flax. It measures 2.6 to 5.5 mm long by 1.4 to 2.9 mm wide and lacks the tail that characterizes the long tailed mealybug. The body is covered with a fine mealy, wax secreation and often the white fluffy ovisac that forms can completely hide the insect.
This insect has been a pest of New Zealand Flax since its discovery in California on the University of California Berkeley campus in 1906 where it was first misidentifiied as Pseudococcus diminutus. Up until the 1960's it appears that this insect was localized in the San Francisco Bay area but became more wide spread with the popularity of New Zealand Flax in the 1980's. The name Trionymus diminutus was applied to this species and later changed to Balanococcus diminutus. It is also known to inhabit Cordyline, Agave, Yucca and Fraxinus.
The New Zealand Flax Mealybug, also called Phormium Mealybug is not only unsightly but can sap enough of a plant's vital fluids to cause problems if not controlled. The best control for this insect is removal of infected plant parts and an application of a systemic insecticide, which takes time and possibly repeated applications to fully control. Weaker variegated weeping hybrid varieties often succumb to this pest if not treated while the stronger more upright plants can survive for years while still infested. Unfortunately this pest is now prevalent throughout the California nursery industry.