[3] A small number of quinquelocular sessile pores exist on the ventral abdominal segments in association with respiratory openings called spiracles.
[3] Contrastingly, long tubular ducts ending in cup-shaped pores cover the dorsum in moderate numbers, also concentrating on abdominal segments.
[3] Eriococcus orariensis female anal lobes are cylindrical for two-thirds their length before tapering towards the base of much longer caudal (tail-like) setae.
[2] A prominent feature used to differentiate E. orariensis from other Eriococcus species in a key created by the entomologist, Dr James Mather Hoy,[3] are three dorsal setae on the anal lobe: two towards the base and one two-thirds the distance up towards the inner margin.
[4] There they are widely distributed through Southern and Eastern Australia, including Tasmania,[4] but populations exist in low numbers there due to an abundance of natural predators and parasitoid species.
[2] Initially, Eriococcus orariensis appeared restricted to Orari Gorge, with a slow spread through surrounding Geraldine through the 1940s.
[1] However, in the late 1940s-50s E. orariensis was deliberately spread to farms across the country due to its ability to kill mānuka within years of attack, which was considered a major pasture weed at the time.
[4] If air temperatures are above 21 °C, nymphs will begin rapidly moving across the host plant surface 20 minutes after hatching in search of a feeding site.
[4] Using their antennae to feel the bark surface, this search can take hours to days until the nymph finds a suitable crevice to wedge itself into and insert its mouthparts.
[4] Puparium sacs are completed from waxy filaments excreted from dorsal tubular ducts 4–6 days after a site is found.
[2] Within two hours of fertilisation, females drastically increase production of waxy threads from their sessile pores and tubular ducts, encasing themselves in a sac within 4–6 days, ready for egg laying.
[2] It then inserts its piercing, sucking mouthparts into the plant tissue, arching its body and thrusting forwards to push itself deeper.
[2] Despite initial devastation of Eriococcus orariensis on mānuka populations across New Zealand, its numbers plummeted from the late 1950s onwards, following the likely accidental introduction of the entomogenous fungi, Angatia thwaitesii, from Australia.
[4] This partially explains why species like E. campbelli and E. leptospermi have replaced E. orariensis as successful mānuka scale insects nationwide.
[3] Perhaps the most interesting thing about Eriococcus orariensis, apart from its drastic population bottleneck associated with Angatia thwaitesii, is the lengths people took to spread a known plant blight.
[4] Additionally, their sugar excretions promote the growth of the sooty mold, Capnodium walteri Sacc, 1893, which reduces plant photosynthetic capacity.
[5] Far from causing concern as the discovery of a new blight might today, Eriococcus orariensis was quickly and widely adopted by farmers to remove mānuka, which was perceived as a pesky, economically damaging weed.