Current situation of Bactrocera zonata in Réunion
In Réunion, 4 fruit fly species are currently present. Ceratitis catoirii is indigenous, and the following three species have been introduced: C. capitata (EPPO A2 list - recorded in 1939), C. rosa (EPPO A2 list - 1955) and Bactrocera zonata (EPPO A2 list - 1991). After its introduction, B. zonata remained under control for approximately 10 years, but in 2000 high populations were observed in the northern part of the island. Eradication, using the male annihilation technique, was attempted but failed as B. zonata had spread to most lowland areas. In order to study population dynamics, trimedlure and methyl-eugenol traps were placed at the West and South of the island. In 2004, trapping results showed a predominance of B. zonata compared to Ceratitis species in lowlands (up to altitude of 300 m). C. rosa was predominant at altitudes of 600 m and was almost the only species found above 900 m. In addition, a seasonal variation of populations was shown in 2004/2005. In Réunion, the host range of B. zonata (around 10 plant species) is narrower than the one for C. capitata (29 species) and C. rosa (34 species), but B. zonata is found on host fruits which are widely grown on the island (e.g. Terminalia catappa, Psidium guajava, P. cattleianum and Mangifera indica). Finally, research is being conducted on the possible use of Fopius arisanus (Hymenoptera: Braconidae) as a biological control agent to regulate populations of B. dorsalis and C. capitata, and to develop integrated management programmes adapted to the various combinations of fruit fly species occurring in the orchards.
Sources
Quilici S, Duyck PF, Rousse P, Gourdon, F, Simiand C, Frank A (2005) La mouche de la pêche sur mangue, goyave, etc. à la Réunion, évolution des recherches et des méthodes de lutte. Phytoma – La Défense des Végétaux, no. 584, 44-47.