HortFACT
Identification
The adult female is about 3 mm long, oval, and wingless, with very short antennae and legs that are not visible when the mealy bug is viewed from above. The yellowish-grey body is largely obscured by the powdery white wax with which the mealy bug covers itself, except for a slightly darker stripe running up the middle of the back. Around the edge of the body this wax is extended into a fringe of filaments, of which the hindmost two are exceptionally long, giving this mealy bug its common name.
Two other mealy bugs that may be found infesting the same hosts as the longtailed mealy bug can be distinguished from it as follows. The citrophilus mealy bug (P. calceolariae) has two longitudinal dark stripes on its back, and the body contents, revealed when the mealy bug is crushed, are bright red. The obscure mealy bug (P. obscures) has no dark stripes and the body contents are pinkish grey. Neither the citrophilus mealy bug nor the obscure mealy bug has the long 'tail' filaments that characterise the longtailed mealy bug.
The adult male is about 1 mm long, with a red body and a single pair of transparent wings. Two filaments of white wax project from the end of its abdomen.
The first-instar nymph, or crawler, is about 0.3 mm long and similar in shape to the adult female, except that the legs and antennae are relatively larger and the yellow body is not obscured by wax.
The second- and third-instar nymphs are smaller replicas of the adult female, but may be more yellow.
The male cocoon is composed of cottony white wax, and is about I mm long.
Host plants
Outdoors, the longtailed mealy bug is a pest of a wide range of fruit trees, including apple, citrus, pear, and grapevines, and more rarely stone fruits. Under glasshouse conditions, mealy bugs can be found infesting almost any plant.
Damage
Mealy bugs feed on plant juices, and heavy infestations may seriously weaken the host plant The more usual form of damage is disfiguration of leaves and fruit, caused by the excess wax produced during reproduction and by the honeydew that is secreted by the mealy bugs. Sometimes a black, sooty mould grows on this honeydew, further disfiguring the host plant.
Distribution
The longtailed mealy bug occurs throughout the world as a major pest of glasshouse plants, and in warmer areas as a pest of outdoor fruit trees. In New Zealand it is found outdoors throughout the North Island and in the northern part of the South Island. Under glasshouse conditions it occurs throughout the country.
Life cycle
| Egg |  |
| Crawler | |
| Nymph | |
| Adult | |
| Month | |
| Note: Coloured bars indicate periods of peak activity in each of the life cycle stages | |
There are three or four generations each year, depending on the climate. During summer all life stages are found on the leaves and fruit, but as the weather becomes colder the mealy bugs retreat under the bark of the host plant. Here reproduction continues, but at a much slower rate, throughout the winter. Breeding activity increases in spring, and many crawlers are born at just the right time to start feeding on the new foliage. The life span of each generation is greatly dependent on temperature, and can be from I to 4 months depending on the time of year.
Longtailed mealy bugs give birth to live young; each female produces about 200 crawlers in a cottony mass of wax secretion. Female crawlers pass through three instars (growth stages) before becoming adult. Males pass through only two, which superficially appear identical to the first two instars of the female They then spin a white cocoon, push the cast second-instar skin to the end of it, and enter a prepupal stage. Shortly after pupation the winged males emerge, and later find and mate with the much larger wingless females.
JENNIFER COX