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Long egg-sac mealybug - Paracoccus glaucus

By N A Martin (2018)

Classification

Phylum:
Arthropoda
Class:
Insecta
Order:
Hemiptera
Superfamily:
Coccoidea
Family:
Pseudococcidae
Scientific Name:
Paracoccus glaucus (Maskell, 1879)
  • Two female Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the pair of white wax tails. Image: Tim Holmes © Plant & Food Research
    Two female Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the pair of white wax tails. Image: Tim Holmes © Plant & Food Research
  • A female Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) with an egg sac and first instar (stage) nymphs on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the white wax covering the old female. Image: Tim Holmes © Plant & Food Research
    A female Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) with an egg sac and first instar (stage) nymphs on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the white wax covering the old female. Image: Tim Holmes © Plant & Food Research
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Common Names

Long egg-sac mealybug
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Synonyms

Dactylopius glaucus Maskell, 1879
Pseudococcus glaucus (Maskell, 1879)
Trionymus morrisoni Brittin, 1938
Paracoccus morrisoni (Brittin, 1938)

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Biostatus and Distribution

The endemic Long egg-sac mealybug lives on ferns and leaves of trees and shrubs in the North & South Islands. As its name suggests it has distinctive long egg sacs.

Conservation status: This native mealybug is not endangered and is found in native ecosystems in the North & South Islands.

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Life Stages and Annual Cycle

Diagramme of the life cycle of a typical mealybug (Hemiptera: Pseudococcidae). Image: JM Cox © Drawing published in Fauna of New Zealand 11:1-228, Fig. 1.
Diagramme of the life cycle of a typical mealybug (Hemiptera: Pseudococcidae). Image: JM Cox © Drawing published in Fauna of New Zealand 11:1-228, Fig. 1.

The Long egg-sac mealybug appears to breed all year. There do not appear to be discrete generations. It is not known how long it takes from egg to adult. All stages live on the leaves of its host plants.

The adult female is oval, about 3-4 mm long and 2 mm wide. The body varies from pale green to orange-red with a darker line by the midline. The body is lightly covered with powdery white wax. There is a terminal pair of white wax filaments, and smaller white wax filaments at the front and along the edge of the abdomen. The mature female has a pair of short antennae and three pairs of legs. There is no distinct division between the head or thorax (middle section of the body) and abdomen. On the underside of the head there is a short rostrum that guides the feeding stylets. After mating and when it is fully grown, the female mealybug settles on a leaf and produces a white fluffy wax chamber at the rear end of its body. It lays orange coloured eggs into the egg sac. As it fills up, the female mealybug moves forward making the sac longer as it continues to lay more eggs. The female body gradually shrinks and the white wax covering becomes denser.

Nymphs hatch from the eggs and leave the egg sac. The nymphs are like small orange-brown adult females. There are three female nymphal instars (stages) and two male nymphal instars. These feeding stages grow by moulting (changing skin). The second instar male makes a fluffy white cocoon in which develop two pre-adult non-feeding stages, a prepupa and a pupa. The prepupa and pupa have wing buds. The adult male emerges from the pupa. The moulted prepupal and pupal skins are pushed out the end of the cocoon. The adult male does not have a rostrum or stylets and does not feed. When it is ready to emerge from the cocoon, the back end of the cocoon is pushed open and the male backs out. After it has opened the back of the cocoon, its wings (1 pair) expand and harden. It also grows a pair of long wax tails. It is presumed that the wax tails help balance the insect in flight. The male may mate with females of the same colony or fly to another colony to mate.

Feeding and honeydew
Mealybug adult females and nymphs have sucking mouthparts. Specially shaped rods called stylets are held in the short sheath-like rostrum. When it wishes to feed, the mealybug moves the tip of the rostrum onto the surface of the plant leaf or stem. The stylets are then gradually pushed into the plant and manoeuvred into the phloem (nutrient transport vessels) of the plant. The mealybugs suck the plant’s sap, which is high in sugars and low in other nutrients. Mealybugs have a short white wax anal tube through which they excrete the excess sugary liquid, which is called honeydew.

Walking, flying and dispersal
The adult male has legs and wings. It can walk around the leaves where its cocoon was and it can fly to other leaves or to different trees. Adult females and nymphs also have legs and can walk. They may move about the group of leaves where they were born. In other insects with a none flying adult female, the first stage larvae or nymphs are able to disperse to new trees. They usually do this using the wind. It is likely that some first instar nymphs climb to a prominent place on a leaf or branch and await a gust of wind.

  • Two female Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the pair of white wax tails. Image: Tim Holmes © Plant & Food Research
    Two female Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the pair of white wax tails. Image: Tim Holmes © Plant & Food Research
  • Female Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note short egg sac forming behind the female. Image: Tim Holmes © Plant & Food Research
    Female Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note short egg sac forming behind the female. Image: Tim Holmes © Plant & Food Research
  • A female Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) with a short egg sac and on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
    A female Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) with a short egg sac and on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
  • A female Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) with an egg sac and first instar (stage) nymphs on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the white wax covering the old female. Image: Tim Holmes © Plant & Food Research
    A female Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) with an egg sac and first instar (stage) nymphs on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the white wax covering the old female. Image: Tim Holmes © Plant & Food Research
  • An old egg sac of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the white wax covering the dead female. Image: Tim Holmes © Plant & Food Research
    An old egg sac of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the white wax covering the dead female. Image: Tim Holmes © Plant & Food Research
  • Nymphs arround an old egg sac of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Most of the nymphs are second instar (stage): note the white moulted skins. Image: Tim Holmes © Plant & Food Research
    Nymphs arround an old egg sac of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Most of the nymphs are second instar (stage): note the white moulted skins. Image: Tim Holmes © Plant & Food Research
  • Nymphs arround an old egg sac of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the white moulted skins. Image: Tim Holmes © Plant & Food Research
    Nymphs arround an old egg sac of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the white moulted skins. Image: Tim Holmes © Plant & Food Research
  • White male cocoons of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
    White male cocoons of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
  • White male cocoons of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the wings and white wax tail protruding from the bottom left cocoon. Image: Tim Holmes © Plant & Food Research
    White male cocoons of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the wings and white wax tail protruding from the bottom left cocoon. Image: Tim Holmes © Plant & Food Research
  • Adult male Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
    Adult male Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
  • An underside of an adult male Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
    An underside of an adult male Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
  • Side view of an adult male Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
    Side view of an adult male Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
  • An adult male on cocoons of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
    An adult male on cocoons of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
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Recognition

Mealybugs (Pseudococcidae) require specialist skills for their identification. However, when some species are on their host plants they have distinct features that enables them to be named with confidence. The Long egg-sac mealybug is one such species. The oval adult females are pale green to orange-red, with a darker line by the midline. The body is lightly covered with powdery white wax and has short filaments of white wax at the front and back with one pair of strong white wax filaments at the back. The other distinguishing feature is the long egg sac made by the female.

The mealybug, Paracoccus zealandicus (Ezzat & McConnell, 1956) has some similarities to Long egg-sac mealybugs. Notably they have the same white wax filaments at the front and back and a thin powdery white wax covering of the body. However, the underlying colour of Paracoccus zealandicus dark purplish-brown.

  • An adult female and nymphs of Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the pair of white wax tails. Image: Tim Holmes © Plant & Food Research
    An adult female and nymphs of Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the pair of white wax tails. Image: Tim Holmes © Plant & Food Research
  • A female Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) with an egg sac and first instar (stage) nymphs on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the white wax covering the old female. Image: Tim Holmes © Plant & Food Research
    A female Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) with an egg sac and first instar (stage) nymphs on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the white wax covering the old female. Image: Tim Holmes © Plant & Food Research
  • An adult female, nymphs and an adult male probably of Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the pair of white wax tails and the reddish colour of the adult female and large nymphs. Image: Tim Holmes © Plant & Food Research
    An adult female, nymphs and an adult male probably of Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the pair of white wax tails and the reddish colour of the adult female and large nymphs. Image: Tim Holmes © Plant & Food Research
  • Two adult females and an adult male of Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Nicholas A. Martin © Nicholas A. Martin
    Two adult females and an adult male of Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Nicholas A. Martin © Nicholas A. Martin
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Natural Enemies

No pathogens of the Long egg-sac mealybug, Paracoccus glaucus are known.

Parasitoids
One parasitoid wasp (Hymenoptera) has been reared from Long egg-sac mealybugs.

Predators
Several predators have been observed feeding on the mealybugs. These include three species of ladybird (two adventive and one endemic species) and larvae of two kinds of flies, predatory gall flies (Cecidomyiidae) and hoverflies (Syrphidae). The predatory Red-cross mirid has also been found associated with mealybug colonies.

Table: Natural enemies of Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae), from Plant-SyNZ database (25 April 2018). The reliability index shows the quality of evidence for the host association (0-10, 10=high quality).
Scientific NameCommon NameClassificationEnemy TypeReliability IndexBiostatus
Adelencyrtoides unicolor Noyes, 1988 (Wasp)Hymenoptera: Encyrtidaeparasitoid10endemic
Cecidomyiidae sp. 'predators' (Fly)Diptera: Cecidomyiidaepredator5unknown
Cryptolaemus montrouzieri Mulsant, 1853Mealybug ladybird (Beetle)Coleoptera: Coccinellidaepredator10adventive
Diomus sp. nr subclarus (Blackburn, 1895)Diomus mealybug ladybird (Beetle)Coleoptera: Coccinellidaepredator9adventive
Rhyzobius sp. 1 (Kuschel 1990)Native mealybug ladybird (Beetle)Coleoptera: Coccinellidaepredator9endemic
Syrphidae sp.(Fly) Diptera: Syrphidae)predator5unknown
Zanchius rubicrux Eyles, 2005Red-cross mirid (Sucking bug)Hemiptera: Miridaepredator6endemic
  • Larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
    Larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
  • Larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
    Larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
  • Larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Nicholas A. Martin © Plant & Food Research
    Larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Nicholas A. Martin © Plant & Food Research
  • Larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Nicholas A. Martin © Plant & Food Research
    Larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Nicholas A. Martin © Plant & Food Research
  • Cocoon being made by a larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae) after feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
    Cocoon being made by a larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae) after feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
  • Cocoon being made by a larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) after feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
    Cocoon being made by a larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) after feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
  • Cocoon being made by a larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) after feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
    Cocoon being made by a larva of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) after feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
  • Cocoon of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) after feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
    Cocoon of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) after feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
  • Pupa exposed by opening cocoon of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) after feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
    Pupa exposed by opening cocoon of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) after feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
  • Empty pupal case protruding from cocoon of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). When the adult is ready to emerge, the pupal protrudes from one end of the cocoon. Image: Tim Holmes © Plant & Food Research
    Empty pupal case protruding from cocoon of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). When the adult is ready to emerge, the pupal protrudes from one end of the cocoon. Image: Tim Holmes © Plant & Food Research
  • Empty pupal case protruding from cocoon of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae). Image: Tim Holmes © Plant & Food Research
    Empty pupal case protruding from cocoon of a predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae). Image: Tim Holmes © Plant & Food Research
  • Adult predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) whose larva had fed on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
    Adult predatory gallfly, Cecidomyiidae sp. 'predators' (Diptera: Cecidomyiidae) whose larva had fed on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
  • Larva of a Hoverfly, Syrphidae sp. (Diptera: Syrphidae) feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
    Larva of a Hoverfly, Syrphidae sp. (Diptera: Syrphidae) feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
  • Larva of a Hoverfly, Syrphidae sp. (Diptera: Syrphidae) feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
    Larva of a Hoverfly, Syrphidae sp. (Diptera: Syrphidae) feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae). Image: Tim Holmes © Plant & Food Research
  • Larvae of mealybug ladybird, Cryptolaemus montrouzieri (Coleoptera: Coccinellidae), feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
    Larvae of mealybug ladybird, Cryptolaemus montrouzieri (Coleoptera: Coccinellidae), feeding on Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
  • Adult mealybug ladybird, Cryptolaemus montrouzieri (Coleoptera: Coccinellidae). © Plant & Food Research
    Adult mealybug ladybird, Cryptolaemus montrouzieri (Coleoptera: Coccinellidae). © Plant & Food Research
  • A fully grown larva of mealybug ladybird, Cryptolaemus montrouzieri (Coleoptera: Coccinellidae) eating a small mealybug (left). © Plant & Food Research
    A fully grown larva of mealybug ladybird, Cryptolaemus montrouzieri (Coleoptera: Coccinellidae) eating a small mealybug (left). © Plant & Food Research
  • Larva of Diomus mealybug ladybird, Diomus sp. nr subclarus (Blackburn, 1895) (Coleoptera: Coccinellidae). Image: Nicholas A. Martin © Plant & Food Research
    Larva of Diomus mealybug ladybird, Diomus sp. nr subclarus (Blackburn, 1895) (Coleoptera: Coccinellidae). Image: Nicholas A. Martin © Plant & Food Research
  • Larva of Native mealybug ladybird, Rhyzobius sp. 1 (Coleoptera: Coccinellidae) feeding on mealybugs on kawakawa (Piper excelsum). Image: Nicholas A. Martin © Plant & Food Research
    Larva of Native mealybug ladybird, Rhyzobius sp. 1 (Coleoptera: Coccinellidae) feeding on mealybugs on kawakawa (Piper excelsum). Image: Nicholas A. Martin © Plant & Food Research
  • Larva of Native mealybug ladybird, Rhyzobius sp. 1 (Coleoptera: Coccinellidae) feeding on mealybugs on kawakawa (Piper excelsum). Image: Nicholas A. Martin © Plant & Food Research
    Larva of Native mealybug ladybird, Rhyzobius sp. 1 (Coleoptera: Coccinellidae) feeding on mealybugs on kawakawa (Piper excelsum). Image: Nicholas A. Martin © Plant & Food Research
  • Adult Native mealybug ladybird, Rhyzobius sp. 1 (Coleoptera: Coccinellidae) about 2 mm long. Image: Tim Holmes © Plant & Food Research
    Adult Native mealybug ladybird, Rhyzobius sp. 1 (Coleoptera: Coccinellidae) about 2 mm long. Image: Tim Holmes © Plant & Food Research
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Host Plants

The Long egg-sac mealybug lives on ferns, shrubs, trees and climbers. It is mainly found on indigenous plants, by has been found on cultivated and naturalised species. It mainly lives on the underside of leaves, but on Puriri, Vitex lucens (Labiatae), nymphs may be found on the upper side of leaves, especially along the midrib. The young mealybugs often settle by against something prominent on the leaf. The most distinctive characteristic of this species is the long, often coiled egg sac made on the underside of leaves by the female mealybug.

Feeding and honeydew
Mealybug adult females and nymphs have sucking mouthparts. Specially shaped rods called stylets are held in the short sheath-like rostrum. When it wishes to feed, the mealybug moves the tip of the rostrum onto the surface of the plant leaf or stem. The stylets are then gradually pushed into the plant and manoeuvred into the phloem (nutrient transport vessels) of the plant. The mealybugs suck the plant’s sap, which is high in sugars and low in other nutrients. Mealybugs have a short white wax anal tube through which they excrete the excess sugary liquid, which is called honeydew.

Table: Host plants of the Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae) from Plant-SyNZ database (25 April 2018). The reliability score shows the quality of evidence for the host association (1-10, 10=high).
Common Name(s)Scientific NameFamilyReliability IndexBiostatus
Shining spleenwort, Huruhuruwhenua, Parenako, Paretao, Pānako, Paranako, Paretao, Urūru whenuaAsplenium oblongifolium ColensoAspleniaceae10endemic
Hard fern, Kiokio, Water fernBlechnum sp.Blechnaceae7unknown
Lance fernLoxogramme dictyopteris (Mett.) Copel.Polypodiaceae10endemic
Hanging clubmoss, Tassel fern, IwitunaPhlegmariurus varius (R.Br.) A.R.Field & BostockLycopodiaceae10endemic
New Zealand ash, Tapitapi, Tītoki, Tītongi, Tokitoki, Tongitongi, TopitopiAlectryon excelsus Gaertn.Sapindaceae10endemic
Shrubby honeysuckle, Horopito, Karapapa, Korotaiko, Pere, ToropapaAlseuosmia macrophylla A. Cunn.Alseuosmiaceae10endemic
Wineberry, Mako, MakomakoAristotelia serrata (J.R.Forst. & G.Forst.) W.R.B.OliverElaeocarpaceae10endemic
Mangrove, MānawaAvicennia marina (Forsk.) Vierh. subsp. australasica (Walp.) J.EverettAcanthaceae10indigenous, non-endemic
Marble leaf, Motorbike tree, Kaiwētā, Piripiriwhata, Punawētā, Putaputawētā, PutawētāCarpodetus serratus J.R.Forst. & G.Forst.Rousseaceae10endemic
English grapefruitCitrus ×paradisi Macfad.Rutaceae10cultivated
LemonCitrus limon (L.) Burm.f.Rutaceae10naturalised
Coprosma colensoi Hook.f.Rubiaceae10endemic
Coprosma crassifolia ColensoRubiaceae10endemic
Kākawariki, Kanono, Kapukiore, Karamū-kueo, Kueo (fruit), Manono, Pāpāuma, Raurēkau, ToherāoaCoprosma grandifolia Hook.f.Rubiaceae10endemic
Coprosma polymorpha W.R.B.OliverRubiaceae10endemic
Cabbage tree, Giant dracena, Grass palm, Palm lily, Sago palm, Ti, Kāuka, Kiokio, Kōuka, Tī, Tī awe, Ti kōuka, Tī para, Tī pua, Tī rākau, WhanakeCordyline australis (G.Forst.) Endl.Asparagaceae10endemic
Mountain cabbage tree, Broad-leaved cabbage tree, Tī kapu, Tī kupenga, Tī matuku-tai, Tī tōī, TōīCordyline indivisa (G.Forst.) Endl.Asparagaceae10endemic
Sticky hop-bush, ake, Ake rautangi, AkeakeDodonaea viscosa Jacq. subsp. viscosa Jacq.Sapindaceae10indigenous, non-endemic
KiekieFreycinetia banksii A.Cunn.Pandanaceae9endemic
New Zealand privet, Hangehange, Hengahenga, Pāhengahenga, Pāpā, Pāpāhenga, Pāpāuma, Whangewhange Geniostoma ligustrifolium A.Cunn. var. ligustrifolium Loganiaceae 10endemic
Pigeonwood, Kaiwhir, Kaiwhiria, Kōporokaiwhiri, Pōporokaiwhiri, Pōporokaiwhiria, Porokaiwhiri, Porokaiwhiria, PoroporokaiwhiriaHedycarya arborea J.R.Forst. & G.Forst.Monimiaceae10endemic
Lacebark, Ribbonwood, HouhereHoheria sp.Malvaceae7endemic
Whiteywood, Hinahina, Inaina, Inihina, Māhoe, Moeahu, KaiwetaMelicytus ramiflorus J.R.Forst. & G.Forst.Violaceae10indigenous, non-endemic
White rata, RātāMetrosideros diffusa (G.Forst.) Sm.Myrtaceae10endemic
Myrtle, Rōhutu, rōutuNeomyrtus pedunculata (Hook.f.) AllanMyrtaceae10endemic
Flax, Lowland flax, New Zealand flax, Swamp flax, Harakeke, Harareke, KōrariPhormium tenax J.R.Forst. & G.Forst.Hemerocallidaceae10endemic
Pepper tree, Kawa, KawakawaPiper excelsum G.Forst.Piperaceae10endemic
Mock orange, Pittosporum, Victorian box, KohukohuPittosporum sp.Pittosporaceae7endemic
Alpine pepper tree, Mountain horopito, Pepper tree, Red horopito, Horopito, ōramarama, RamaramaPseudowintera colorata (Raoul) DandyWinteraceae10endemic
Quintinia, Kūmarahou, TāwheowheoQuintinia serrata A.Cunn.Paracryphiaceae10endemic
Supplejack, Akapirita, Kakareao, Kakarewao, Kareao, Karewao, Kekereao, Pirita, TaioreRipogonum scandens J.R.Forst. & G.Forst.Ripogonaceae10endemic
Bush lawyer, Swamp lawyer, Taraheke, Taramoa, Tātaraheke, Tātarāmoa, Tātarāmoa-turuhungaRubus australis G.Forst.Rosaceae10endemic
Seven-finger, Kohi, Kotētē, Patate, Patatē, Patē, PatētēSchefflera digitata J.R.Forst. & G.Forst.Araliaceae10endemic
Coastal kowhaiSophora chathamica CockayneLeguminosae10endemic
New Zealand oak, Kauere, PūririVitex lucens KirkLabiatae10endemic
Kāmahi, Tawhero, TōwaiWeinmannia racemosa L.f.Cunoniaceae10endemic
  • Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on underside of fronds of Lance fern, Loxogramme dictyopteris (Polypodiaceae). Image: Nicholas A. Martin © Plant & Food Research
    Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on underside of fronds of Lance fern, Loxogramme dictyopteris (Polypodiaceae). Image: Nicholas A. Martin © Plant & Food Research
  • Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on the underside of a leaf of Mahoe, Melicytus ramiflorus (Violaceae). Image: Nicholas A. Martin © Plant & Food Research
    Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on the underside of a leaf of Mahoe, Melicytus ramiflorus (Violaceae). Image: Nicholas A. Martin © Plant & Food Research
  • Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on the underside of a leaf of Mahoe, Melicytus ramiflorus (Violaceae). Image: Nicholas A. Martin © Nicholas A. Martin
    Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on the underside of a leaf of Mahoe, Melicytus ramiflorus (Violaceae). Image: Nicholas A. Martin © Nicholas A. Martin
  • Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on the underside of a leaf of Supplejack, Ripogonum scandens (Ripogonaceae). Image: Nicholas A. Martin © Plant & Food Research
    Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on the underside of a leaf of Supplejack, Ripogonum scandens (Ripogonaceae). Image: Nicholas A. Martin © Plant & Food Research
  • Juvenile Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on the upper side of a leaf of Puriri, Vitex lucens (Labiatae). Image: Nicholas A. Martin © Plant & Food Research
    Juvenile Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on the upper side of a leaf of Puriri, Vitex lucens (Labiatae). Image: Nicholas A. Martin © Plant & Food Research
  • Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on young leaves of Kiekie, Freycinetia banksii (Pandanaceae). Image: Nicholas A. Martin © Plant & Food Research
    Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on young leaves of Kiekie, Freycinetia banksii (Pandanaceae). Image: Nicholas A. Martin © Plant & Food Research
  • Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a mature leaf of Kiekie, Freycinetia banksii (Pandanaceae). Image: Nicholas A. Martin © Plant & Food Research
    Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a mature leaf of Kiekie, Freycinetia banksii (Pandanaceae). Image: Nicholas A. Martin © Plant & Food Research
  • Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on the underside of a leaf of Hangehange, Geniostoma ligustrifolium (Loganiaceae). Image: Nicholas A. Martin © Plant & Food Research
    Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on the underside of a leaf of Hangehange, Geniostoma ligustrifolium (Loganiaceae). Image: Nicholas A. Martin © Plant & Food Research
  • Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on the underside of a leaf of Kawakawa, Piper excelsum (Piperaceae). Image: Nicholas A. Martin © Nicholas A. Martin
    Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on the underside of a leaf of Kawakawa, Piper excelsum (Piperaceae). Image: Nicholas A. Martin © Nicholas A. Martin
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Additional Information

Why is there so much white wax?
Most mealybugs produce much white flocculent wax with which they are covered and which also covers the areas of plants they inhabit. To the human eye this makes it much easier to find the colonies of mealybugs. However, does it make it easier for predators and parasitoids to find them, or is the white wax some kind of deterrent and warning colouration? Other insects with a scale stage also cover themselves with white wax. This suggests to me that it may be some kind of deterrent and warning.

Research Project: Colour variation of adult females
Jenifer Cox in her 1987 paper on the taxonomy of New Zealand Mealybugs discusses the similarity between the Long egg-sac mealybug, Paracoccus glaucus and Paracoccus zealandicus (Ezzat & McConnell, 1956). Both are oval shaped, covered by thin powdery white wax and have the same wax filaments at the front and back. The main difference between live adult females is that the underlying colour of P. zealandicus are dark purplish brown, while those of the Long egg-sac mealybug are pale, bright green, or sometimes a pale, bright orange. These colour differences were used to determine the taxonomic characters used to distinguish the two species. Jenifer thought that further studies, particularly host-transfer experiments, may change this interpretation. This problem seems to me to be a good candidate for the use of molecular biology.

  • An adult female and nymphs of Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the pair of white wax tails. Image: Tim Holmes © Plant & Food Research
    An adult female and nymphs of Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the pair of white wax tails. Image: Tim Holmes © Plant & Food Research
  • An adult female, nymphs and an adult male probably of Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the pair of white wax tails and the reddish colour of the adult female and large nymphs. Image: Tim Holmes © Plant & Food Research
    An adult female, nymphs and an adult male probably of Long egg-sac mealybugs, Paracoccus glaucus (Hemiptera: Pseudococcidae) on a leaf of New Zealand flax, Phormium tenax (Hemerocallidaceae): note the pair of white wax tails and the reddish colour of the adult female and large nymphs. Image: Tim Holmes © Plant & Food Research
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Information Sources

Cox JM. 1987. Pseudococcidae (Insecta: Hemiptera). Fauna of New Zealand. 11: 1-230.

Plant-SyNZ: Invertebrate herbivore-host plant association database. plant-synz.landcareresearch.co.nz/.


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Acknowledgements

The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research) for permission to use photographs.

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Other Images

  • Adult male Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
    Adult male Long egg-sac mealybug, Paracoccus glaucus (Hemiptera: Pseudococcidae). Image: Tim Holmes © Plant & Food Research
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Suggested Citation

Martin NA. 2018. Long egg-sac mealybug - Paracoccus glaucus. Interesting Insects and other Invertebrates. New Zealand Arthropod Factsheet Series Number 136. http://nzacfactsheets.landcareresearch.co.nz/Index.html. Date Accessed. ISSN 1179-643X.

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