Leaf-footed bug, squash bug
Leptoglossus species; Leptoglossus gonagra (previosuly known as Leptoglossus australis) is the common species in the Pacific islands.
Widespread. Asia, Oceania. It is recorded from Australia, American Samoa, Fiji, French Polynesia, Guam, Federated States of Micronesia, North Mariana Islands, Palau, Papua New Guinea, Samoa, Solomon Islands, Tonga, Vanuatu, Wallis & Futuna.
Snake gourd, melon, cucumber, pumpkin and other cucurbits. Many other plants, including, citrus, eggplant, guava, legumes, passionfruit and tomato, are reported as hosts.
Damage is caused by both nymphs and adult bugs sucking sap from stems and tender fruits. The bugs feed using their long tube-like mouths to draw sap from stems, fruits and seeds. Stems turn yellow-brown and they may die if infestations are high. Feeding on fruits causes them to shrivel, rot and drop.
The eggs are laid on the leaves and stems, and even on the tendrils, in batches of about 30. They hatch in 6-7 days. There are five nymph stages over 40-50 days. Young nymphs are reddish, but as they pass from one moult to the next they become darker (Photo 1). The adults are about 18-24 mm long, black or dark brown, with a curved orange line behind the head, and distinctive orange-red spots on the under surface and sides (Photo 2). They have very long sucking mouthparts, almost as long as their bodies, which they use to feed on fruit of all ages (nymphs feed on stems and leaves).
A distinctive feature of the bug are the outgrowths on the legs of the late stage nymphs and the adults; these are the reason for the common name - leaf-footed bug (Photos 3-5) . The adults live for about 2 weeks.
The bugs are not considered major pests, and only occasionally reach numbers that cause economic damage. Plants in the citrus, cucumber and passionfruit families are most affected.
Look for a large black slow-moving bug with orange spots on the sides and distinctive outgrowths on the hind legs. Look for the nymphs which are red at first, becoming brown as they develop. Look for the very long mouthparts that adults insert to feed on fruit of all ages.
There are no reports of predators or parasitoids attacking Leptoglossus in Pacific island countries. Elsewhere, reduviids (assassin bugs), mantids (preying mantis), spiders and wasps are known to destroy eggs and prey on nymphs.
It is unlikely that infestations would reach levels where chemical control would be necessary, or economically justified. If it is necessary, sprays of derris or pyrethrum should be tried. If a synthetic product is needed, use pyrethroids or malathion.
AUTHOR Grahame Jackson
Photos 1&2 Graham Teakle, Canberra. Photos 3-5 Mani Mua, SPC, Sigatoka Research Station, Fiji.
Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.
This fact sheet is a part of the app Pacific Pests and Pathogens
The mobile application is available from the Google Play Store and Apple iTunes.