Aleurotrachelus atratus hempel (Hemiptera: Aleyrodidae) and its emergence as a pest of coconut (Cocos nucifera L.) in the Comoro Islands

Aleurotrachelus atratus Hempel, 1922 was identified recently in the Comoro Islands, where it appears to be a major pest of Cocos nucifera L.. In Grand Comoro, 90% of coconut palms are severely attacked by whiteflies: namely A. atratus (90%), associated with Paraleyrodes bondari Peracchi, 1971 (10%). The sooty mould that develops on the honeydew excreted by whiteflies worsens the damage and significantly affects coconut palm growth and yields. The economic incidence is substantial with lost earnings for producers estimated at 3 to 5 million euros. Damage is produced also to crops growing under coconut, such as vanilla, banana, physic nut and guava. Although of neotropical origin, A. atratus would appear to have been accidentally introduced to the Comoro Islands and was first considered to be a true threat to coconut in 2000. Recent samples taken from coconut palms show that A. atratus is found on coconut on several Indian Ocean islands, on the African continent, and in central America without causing any great damage. It is the first time that A. atratus has been reported in the Comoro Islands, and in such spectacular outbreaks on coconut anywhere in the world. Chilocorus nigritus Fabricus has been identified locally on colonies of A. atratus, P. bondari, Aspidiotus destructor Signoret, though its predatory action has not been demonstrated. A preliminary study intended to search for natural enemies on the island of Réunion revealed the existence of a parasitoid of the genus Eretmocerus. This parasitic Hymenoptera could be one of the candidates for a future biological control programme to reduce the population levels of the pest. (Texte intégral