Plant Protection Service Secretariat of the Pacific Community Pest Alert No 42 ISSN 1727-8473 October 2008 Incursion of the oriental scale insect Aonidiella orientalis (Newstead) (Hemiptera: Diaspididae) in Tabiteuea- South, Kiribati. The oriental scale insect was first noticed on pawpaw and coconuts in Tabiteuea-South in 2006. A survey was conducted and specimens collected from Tabiteuea-South were sent to the British Museum for identification and authentication. The results confirmed the specimens to be the oriental scale insect Aonidiella orientalis. Further surveys conducted in 2007 found that the scale had spread to both the northern and southern islands in Tabiteuea Atoll. Distribution The oriental scale insect (OSI) has not previously been recorded in Kiribati. It originates in Eastern Asia and is widespread throughout tropical and subtropical countries. In the Pacific region, it is recorded in Australia (tropical and subtropical regions), Nauru, Pawpaw infested with oriental scale insect Mariana Islands, Yap Island and Papua New Guinea. The spread of OSI has mostly occurred through people moving infested plants. Host range and economic importance OSI is highly polyphagous and is recorded as infesting plants from 36 genera and 25 families. The most common food crops infested by OSI include coconut, citrus, pawpaw, mango, avocado pear, banana, breadfruit, guava, cucurbits, eggplant and chilli. Other plants infested by the scale insect include frangipani, rose, hibiscus, oleander, neem, areca nut and many more. OSI is a sap sucker. Its feeding reduces plant vigour, which often leads to discolouration and distortion of leaves. Heavy infestations result in yellowing of foliage and defoliation, dieback of small twigs and premature fruit fall. Infestations also Scale infestation inhibits fruit development cause cosmetic damage to fruit. OSI excretes a substance that attracts ants and leads to development of black sooty mold, which curtails plant photosynthesis, affecting plant growth and development. All stages of a plant, i.e. seedlings, vegetative parts, flowers and fruit, can be infested. The scale insect has the greatest impact in areas where it has been introduced Description and biology The adult females are circular to oval, with a yellowish body and a pinkish-brown scale cover measuring about 2 mm across. The adult males are similar in colour, but smaller and elongate oval. The males have wings and fly around to mate. The females lay eggs or crawlers (first stage of the nymphs) underneath the scale cover. The crawlers move out of the scale cover and settle permanently within a short distance to begin feeding. On average, females take about 45 days and males about 20 days to develop from Early nut or fruit fall may occur, with cracking due to the scale infestation crawlers to adults. Three to five generations may be completed in a year. Control methods Biological control is the best way to keep the insect under control. There are several natural enemies that have been introduced in areas where the pest has invaded. Among the parasitoids are Encarsia citrina, Comperiella lemniscata, Aphytis lingnanensis, A. melinus and Habrolepis aspidioti. The ladybird beetle predators are Chilocorus circumdatus, C. baileyi, C. nigrita, C. bipustulatus, Batrachedra arenosella, Lindorus lophanthae and Telsimia nitida. Cultural control by removing severely infested tree branches and disposing of them properly is likely to be effective against further spread and build up of insect populations. Since the insect does not spread on its own, infested plants should not be disturbed to allow build up of populations of bioagents. Chemical control with narrow-range petroleum oils can be used where there are rapid increases in the scale problem. Chemical applications should stop when build up of bioagent populations is observed. For further information contact: Mr Sada N Lal, Entomologist, Secretariat of the Pacific Community, Private Mail Bag, Suva, Fiji orMs Kinaai Kairo, Director of Agriculture, Ministry of Environment, Lands and Agricultural Development, P. O. Box 234, Bikenibeu, Tarawa, Kiribati..