Pandanas leaf webworm
Aeolarchis sphenotoma. It was known previously as Erechthias fibrivora, and before that Decadarchis fibrivora, the name under which it was described. It is a moth of the Tineidae, fungus moths.
Not known precisely. It has been recorded from Fiji where it is endemic. There is scant literature on this moth. Swaine (1970)1 says that he did not find it in American Samoa or (Western) Samoa.
The larvae or caterpillars do the damage. The larvae web the young leaves together at the tips and feed inside on the outer layers (Photo 1). As the leaves mature, the affected areas become silvery and withered.
The mature larva is about 16 mm long, with a flattened yellow body and red-brown head (Photo 2). The pupa is 9 mm long, red-brown and slightly flattened inside a tough, parchment-like oval cocoon, which is bordered by a crescent-shaped mass of chewed plant tissue and attached to the inside of the webbed leaf (Photo 3).
The adult is 9 mm long and light-brown (Photo 4). The forewings are golden-brown with a V-shaped cream patch; the hindwings are dull-brown, pointed and lightly fringed with thick hairs.
A serious pest which can cause extensive damage to the leaves. Pandanas caricosis and Pandanas thurstoni are important species in Fiji used for making mats, baskets, fans and other handicrafts. Of the two, Pandanas caricocis is considered the best. It is also said to be used to treat diarrhoea.
Look for the damaged leaves, and the larvae with yellow body and red-brown head.
AUTHOR Grahame Jackson & Mani Mua
1Information from Swaine G (1971) Agricultural Zoology in Fiji. Her Majesty's Stationery Office. London.
Produced with support from the Australian Centre for International Agricultural Research under project HORT/2016/18: Responding to emerging pest and disease threats to horticulture in the Pacific islands, implemented by the University of Queensland and the Pacific Community.
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