Plant Protection Service Secretariat of the Pacific Community Pest Alert No. 21 3 April, 2001 Coconut flat moth Agonoxena argaula reported from Rarotonga, Cook Islands In October 2000 the Ministry of Agriculture (MoA) was informed about unhealthy-looking, dying coconut trees with dry leaves in the south east side of Rarotonga. During a survey caterpillars were found feeding on mature leaves causing severe damage. Samples of both caterpillars and emerging adults were identified by CAB International as Coconut Flat Moth Agonoxena argaula. In January 2001 the affected area on Rarotonga covered about 2 km2. The moth is not recorded from other islands in the Southern or Northern Group of the Cook Islands. In the South Pacific the pest is recorded from Fiji, Kiribati, Nauru, New Caledonia, Niue, American Samoa and Samoa, Tokelau, Tonga, Tuvalu, Vanuatu, Hawaii, Wallis and Futuna Islands. It is not known to occur in French Polynesia, Solomon Islands or Papua New Guinea. To minimize the spread of the pest to other parts of Rarotonga and to prevent the spread to outer islands the Ministry of Agriculture urged the public not to take any coconut and ornamental palms, including parts of palms such as leaves, nuts, and trunks, from the infested area. Responsible personnel in the outer islands were directly informed. A public awareness programme was conducted via the media. The Ministry of Agriculture is continually monitoring the pest situation. Agonoxena argaula attacks mainly coconut palms but also other ornamental palms. The adult moth is about 8 mm in length, yellowish brown with narrow pointed wings. The male moth bears a linear white mark on the forewings. Eggs are laid singly or in rows on the underside of a leaflet close to its midrib. The solitary caterpillars feed only on the lower epidermis producing characteristic narrow scars parallel to the veins of the leaf. Caterpillars vary in colour between green and yellow and reach a length of 2 cm when fully grown. When disturbed, caterpillars move rapidly or drop to the ground. Over the leaf they spin a fine web under which they feed. Damage starts usually on middle-aged leaves and continues on older ones. The damage can extend to 40% of the leaf surface of leaflets which results in reduced yields. On Rarotonga two parasitoids were reared from field collected pupae and identified by CAB International as Brachymeria sp. and Trichospilus diatraeae. The former is also recorded from other Pacific Islands; the latter is a new record from the Cook Islands. On average Brachymeria sp. parasitised about 50% of the pupae; 5% were attacked by T. diatraeae. _______________________________________________________________________________________ For further information contact the Cook Islands Research Division (Ph. +682-28720, Fax: +682-21881, e-mail: [email protected]) or Guenther Rapp (Ph. +679-370733 Ext. 224, Fax: +679-370021, e-mail: [email protected]). Communications of pest and disease incidents of interest to the Pacific region should be sent to: Plant Protection Service, Secretariat of the Pacific Community, Private Mail Bag, Suva, Fiji Islands. Tel:(+679) 370733; Fax:(+679)370021; email:[email protected].