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Control of Scapanes australis a major pest of coconut using semiochemicals

Kakul T., Laup S., Ollivier L., Morin J.P., Rochat D.. 2000. In : Gazzoni D.L. (ed.). XXI International congress of entomology. Londrina : EMBRAPA, p. 172-172. (Documentos Embrapa Soja, 143). numero_rapport: N.682. International Congress of Entomology. 21, 2000-08-20/2000-08-26, Foz do Iguaçu (Brésil).

Scapanes australis Bsdv. (Coleoptera, Scarahaeidae) native to the Melariesian region is a major economic pest of coconuts in Papua New Guinea. Adults attack and kill young paints up to 2 years old and feeding sites left on older palms (2 to 7 yeas) are invaded by the secondary pest Black Palm Weevil, Rhynchophorus bilineatus (Coleoptera. Curculionidae), the larvae of which can kill the coconuts. S. australis is a very difficult pest to control because of its long life cycle (356 days) and can also attack palms for tip to 7 years. There has been no effective method of controlling the pest in the past because of the poor knowledge of the insect's biology and ecology. New information on the biology and chemical ecology has recently enabled a mass trapping of the beetle. Various field experiments were carried out to evidence the existence of a long range active pheromone. Field collection of Scapanes during day and night observations had indicated that male Scapanes perform a calling behaviour and emit an aggregation pheromone. Traps were developed initially using cage with calling male as bait. After a year the pheromone was identified and synthetic pheromone became available and was used as attractant. Trapping S. australis first with calling males and latter with synthetic pheromone caused a decline of the population of Scapanes over a period of two years. Whereas trapped females cause the next generation to decline, removed males are prevented from attacking coconuts. Continuous trapping lowers the population of Scapanes overtime hence reduces the threat to coconuts to be attacked by the beetle. Preliminary data had indicated a reduction in the number of coconuts being damaged.
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