Coconut stick insect (102)

Pacific Pests, Pathogens and Weeds - Online edition

Pacific Pests, Pathogens & Weeds

Coconut stick insect (102)

Click/tap on images to enlarge

Photo 1. Male and female stick insect, Graeffea crouani. Note the larger size of the female, but it has smaller wings and cannot fly.

Photo 2. Male and female stick insect, Graeffea crouani.

Photo 3. The stick insects, Graeffea crouani, have stripped the coconut fronds leaving only the midribs.

Summary

Narrow distribution. Southwest Pacific. On coconut, sago palm, Pandanus and some wild palms. Outbreaks occur, when it is an important pest.
Adults strip leaflets, leaving the midrib. Occasionally, defoliation occurs over several hundred hectares. Mature palms >25 m most affected.
Eggs in the crown, fall into the leaf base, leaf litter or weeds. Nymphs climb to the crown. Only males fly.
Natural enemies: chickens and myna birds take nymphs on the ground. There are parasitoid wasps that have been bred for biocontrol.
Cultural control: sticky bands around trunks (e.g., 'Tanglefoot'); control weeds to expose eggs to sun; intercrop with cocoa – nymphs climb the cocoa and starve; note, lighting fires to smoke the insects no longer acceptable as fires damages the palms.
Chemical control: none recommended.

Common Name

Coconut stick insect

Scientific Name

Graeffea crouanii. It is a member of the Phasmatidae.

Photo 4. Group of coconuts attacked by the stick insect, Graeffea crouani.

Photo 5. Close up coconut palm attacked by the stick insect, Graeffea crouani. Note that the palm is recovering from the attack.

AUTHOR Grahame Jackson
Information from Waterhouse DF, Norris KR (1987) Graeffea crouanii (Le Guillou). Biological Control Pacific Prospects. Inkata Press. Assistance also provided by Wilco Liebregts, Eco-Consult Pacific, Fiji. Photo 1 Gerald McCormack, Cook Islands Biodiversity & Natural Heritage. (http://cookislands.bishopmuseum.org/). Photos 2-5 Richard Markham, ACIAR, Canberra.

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.

Web edition hosted at https://apps.lucidcentral.org/pppw