More mealybugs and scale, Fiji

August 2017. During the long discussion on the ant-hemipteran disruption of biological control in Fiji, and elsewhere, a number of scale insects were sent to Pestnet from Fiji. These are they. Note that these are not authoritative identifications – those require examination of high quality slide-mounted specimens.

1. Fan palm (top, left) – Possible armoured scale insects known to be in Fiji that might form dense white colonies (of immature males at least) on palms include: Aspidiotus destructor, Fiorinia proboscidaria, Hemiberlesia cyanophylli, Oceanaspidiotus pangoensis, Pinnaspis buxi, P. strachani, Pseudaulacaspis cockerelli, possiblyP. leveri, P. pentagona and Unaspis citri.

2. Mango (top, right; 2nd row, left) – possibly Planococcus minor.

3. Schlefflera actinohylla, the Queensland umbrella tree. Ceroplastes (Vinsonia) stellifer

4. Morinda (noni) (3rd row, left) – not possible to id without slide-mounted specimens

5. Pritchardia pacifica – Nipaecoccus nipae (coconut mealybug) (3rd row, right). It is difficult to tell from your photo, but I think it is Ni[aecoccus nipae. It has been recorded from Fiji in the literature. Unusually for most mealybugs, the dorsal wax is arranged in cushions rather than being flat; the body contents and crawlers are yellow and the wax varies in colour between pale buff and pale yellow. The adult females are relatively small as mealybugs go. The males develop under small, parallel-sided white wax cocoons that usually occur scattered amongst the females.

There is quite a good picture of an adult female Nipaecoccus nipae at:

http://www.pestnet.org/Portals/32/Images/Insects/9187_MealbugKosrae/Nipaecoccus_n17A.jpg

Quite a lot of other species of Nipaecoccuscan be found on palms, e.g. Nipaecoccus floridensis. Some of them look a bit like Nipaecoccus
nipaebut the wax is white and the adult females are larger. Nipaecoccus floridensis has not been recorded from Fiji. Nipaecoccus viridis(which is present in Fiji) looks quite different – much bigger and very convex at maturity, with dark purple/black body contents and violet eggs and crawlers. The body wax is white and flat initially but in very old females the outer surface often becomes yellowish.
6. Manihot glaziovii (2nd row, right). Saissetia coffeae and Paracoccus sp. However, a member wrote: I don’t think you have hemispherical scale, Saissetia coffeae, because the pale young ones would have a raised H-shaped ridge on their backs, but these do not. It is more likely to be black scale, Parasaissetia nigra, in which the young specimens lack the H-shaped ridge and the backs of the older, mid-brown specimens have a slightly reticulated texture when light shining on the dorsal surface is viewed under magnification.
The mealybug is definitely not papaya mealybug, Paracoccus marginatus, or a species of Planococcus, in which the marginal wax filaments would be shorter and less well defined. The marginal wax filaments are too long, and the rear-end filaments nearest the midline curve away from each other, which makes me wonder whether it could be a Paraputo?

Finally, a mention of Marshall Islands, where a similar situation is said to have existed for a long time. The combination of ants, black sooty mould, and mealy bugs devastated many plants during the last El Nino. Papaya, breadfruit and bele were hit especially hard.