Biological control of Rubus alceifolius (Rosaceae) in La Reunion Island (Indian Ocean): from investigations on the plant to the release of the biological control agent Cibdela janthina (Argidae)

The giant bramble (Rubus alceifolius Poir.: Rosaceae), native to Southeast Asia, is one of the most invasive plants in La Reunion. A ten year research program was launched in 1997 with three components: i) genetic diversity, ii) development strategy, and iii) selection of biological control agents. Introduced populations in La Reunion, Mauritius, Mayotte and Australia were clonal and far from the highly variable native populations in Asia, while Madagascar populations appeared intermediate. Seed production is by apomixis in La Reunion Island and by allogamy in the native habitat. Fruit production occurs up to 1,100 m elevation while vegetative multiplication is possible up to 1,700 m. The plant grows in well lighted places, invading forest edges, and all open areas. From surveys of Rubus natural enemies in its native range, the sawfly Cibdela janthina (Klug) (Argidae) was selected as the most promising biological control agent and studied. The first population was thus released in La Reunion in early 2008 with the agreement of the local authorities for the biological control of R. alceifolius. It is now naturalized, spreading and under evaluation

Biological control of Rubus alceifolius (Rosaceae) in La Réunion Island (Indian Ocean): from investigations of the plant to the release of the biocontrol agent Cibdela janthina (Argidae)

The giant bramble (Rubus alceifolius Poir.: Rosaceae), native to Southeast Asia, is one of the most invasive plants in La Réunion. A ten year research program was launched in 1997 with three components: i) genetic diversity, ii) development strategy, and iii) selection of biological control agents. Introduced populations in La Réunion, Mauritius, Mayotte and Australia were clonal and far from the highly variable native populations in Asia, while Madagascar populations appeared intermediate. Seed production is by apomixis in La Réunion Island and by allogamy in the native habitat. Fruit production occurs up to 1,100 m elevation while vegetative multiplication is possible up to 1,700 m. The plant grows in well lighted places, invading forest edges, and all open areas. From surveys of Rubus natural enemies in its native range, the sawfly Cibdela janthina (Klug) (Argidae) was selected as the most promising biological control agent and studied. The first population was thus released in La Réunion in early 2008 with the agreement of the local authorities for the biological control of R. alceifolius. It is now naturalized, spreading and under evaluation

Le projet régional de malherbologie

Synthèse des recherches préliminaires sur la diversité et le développement des peuplements d'adventices suivant les facteurs écologiques (sols, pluviosité, altitude) et agronomiques (ancienneté de la culture, nature de la plante cultivée, intensification, utilisation d'herbicides), en vue d'optimiser les moyens de lutte intégré