The live adult female is 2.9-5.0 mm long and 2.4-4.0 mm wide, with a pale yellow oval body covered in white wax or sulfur-yellow flocculent wax tinged with white. In the slide-mounted adult female, the antennae each have 9-11 segments and there are three pairs of abdominal spiracles towards the apex of the abdomen. The center of the abdominal venter becomes invaginated to form a marsupium into which the vulva opens, and there is a marsupial band of simple multilocular pores along the lip of the marsupium, which becomes sclerotized with age.
Foliage and stems should be inspected for lumps of white or yellow wax secreted by scale insects, symptoms of pest attack, attendent ants, sticky honeydew and sooty mould growth on leaves. A user-friendly, online tool has been produced for use at US ports-of-entry to help with the identification of potentially invasive scale insect species (Miller et al., 2014a,b).
Related invasive species
- Icerya samaraia
Related Farm Practice
- Damage
- Feeding
- Development
- Defoliation
- Depletion
- Hosts
- Light
The scale insect Icerya samaraia (formerly Steatococcus samaraius) occurs in the Australasian, Oriental and Oceanic zoogeographic regions. It has a wide host range which includes mostly woody plant species in 40 genera belonging to 25 families. It is a minor pest of citrus, banana, coconut, guava, papaya, cocoa, pigeon pea and other plants, including forest and ornamental trees. Populations of I. samaraia are apparently being kept under control on the Palau Islands in the western Pacific Ocean by natural enemies, particularly by the introduced coccinellid Rodolia pumila. I. samaraia can be transported on infested plant materials because of its small size and habit of feeding in concealed areas, making it a potential threat as an invasive species.
Most damage to plants is caused by the early immature stages of I. samarai, which feed on the leaf undersides, settling in rows along the midrib and veins, and on smaller twigs. The older nymphs feed on larger twigs, and as adults they settle on larger branches and the trunk. Damage to plants results from phloem sap depletion during feeding, leading to shoots drying up and dying. Trees that are badly attacked suffer partial defoliation and a general loss of vigour. The insects dischargesugary honeydew, which can be copious in large colonies and may foul plant surfaces. Besides direct damage by feeding, indirect damage can result from the development of black sooty mould on the honeydew on leaf surfaces, blocking light and air from the plant, leading to a reduction in photosynthesis (Beardsley, 1955).
I. samaraia has been reported on mostly woody plant species in 40 genera belonging to 25 families from the Australasian and Oriental zoogeographic regions (Miller et al., 2014a).