Origin:
Native to Australia, but now occurring in other parts of the world where its host trees have been imported as ornamentals.
Biology:
This conspicuous mealybug is very host specific, being found almost exclusively on Norfolk Island Pine in the western U.S., although it will attack a few other kinds of plants. It produces large amounts of honeydew, leading to heavy growth of black sooty mold on the foliage of the plants. Mealybugs favor warm, humid conditions, and will have multiple and overlapping generations under favorable conditions. The female deposits eggs in clumps and covers them with a waxy film, laying an average of 300 eggs in her lifetime. Eggs hatch in 2-10 days. Males undergo 4 instars, and develop to a winged adult is just over 3 weeks. Females go through 3 instar stages, and become the non-winged adult in about 4 weeks. Females live an average of 3 months, while males live only a few days.
Identification:
Easily identified by the dark purplish ground color of the body, with yellow waxy protrusions forming a central band running from front to back and wide, solid yellow margins running around the sides of the insect.
Characteristicts Important to Control:
Where natural predators are active the insect may be kept under control. The “mealybug destroyer” is a ladybird beetle, whose white larvae strongly resemble mealybugs, possibly helping them to blend into a population of the mealybugs as they feed on them. Chemical controls are difficult, but include horticultural oils, often mixed with a contact insecticide. A systemic applied to the soil, such as imidacloprid, can be effective and provide long-term presence of the a.i. in the foliage. Removal of infested plants or plant parts also can be an easy and effective control, but it may be difficult to locate all of the immatures on the plant. Nymphs and adult females are highly mobile.
