Obscure Mealybug – Pseudoccus viburni

Obscure Mealybug (Pseudoccus viburni)

Common Name: Obscure Mealybug

Latin Name: Pseudoccus viburni

Appearance:

• Vintners must differentiate between the cryptic mealybug and its near cousins, the grape and vine mealybug. The filaments of the obscure mealybug are longer, thinner, and more twisted than those of the vine mealybug, giving the obscure mealybug an untidy appearance.
• The set of two to four abnormally long caudal filaments extending from the posterior of giant nymphs and adult females are the most distinguishing characteristic of the cryptic mealybug. The waxy secretion of the insect collects abundantly on these filaments, giving the appearance of multiple lengthy “tails.”
• The obscure mealybug resembles the grape mealybug more than the vine mealybug, although the two may be recognized by the colour of the protective fluid secreted when disturbed; grape mealybugs exude reddish-orange fluid, whilst obscure mealybugs secrete clear fluid.
• The cryptic mealybug’s body contents (guts) appear pinkish-grey when crushed.

Territory:

The obscure mealybug (Pseudococcus viburni) (previously known as Pseudococcus affinis) is native to South America but may now be found in many temperate climates across the globe.

Damages caused by Obscure Mealybug:

There has been an increase in the number of grape mealybug infestations in the San Joaquin Valley and North Coast in recent years, as well as an increase in the prevalence of cryptic and long-tailed mealybugs in Central Coast vineyards. Mealybug susceptibility varies with variety. It is worst on kinds that form clusters towards the base of the shoot because the fruit often comes into contact with aged wood. Mealybugs wreak havoc on grapes by infesting bunches with cottony egg sacs, larvae, adults, and honeydew. A black sooty mould often covers the honeydew. All three species may transmit grape viruses.

Life history and habits:

Mealybugs are so named because, starting in the third nymphal instar, the females’ bodies are coated in a white waxy substance that might take the shape of powder, threads, spiky projections, or platelets. A sticky, frothy mass of wax threads known as an egg sac is where eggs are placed. The female passes away after laying her clutch of eggs. Nymphs in their first instar are yellow-brown and have no wax on them yet. They are referred to as “crawlers” and are actively moving.