Leafy spurge - Euphorbia esula (Euphorbiaceae)
Project Leader: René SFORZA
Euphorbia esula L. subsp. esula, leafy spurge, is a native plant of Eurasia and is commonly distributed in wild and cultivated areas in the Saône Valley in the centre of France. It spreads over large areas in wet prairies. After failure of chemical control, biological control was considered by land managers, and EBCL was contacted in 2003 for giving its expertize. In 2004, a four-month survey over three highly infested wetlands was conducted, and resulted in a collection of insects and a plant pathogen. Two chrysomelid beetles, Aphthona violacea and A. venustula, were of particular interest as the genus was already in the US for a biocontrol programme. These two Aphthona species were collected in the same locality with a peak population in mid July for A. violacea resulting both from yellow sticky traps and sweeping net data. Other natural enemies collected in the Saône Valley that may have a substantial impact on E. esula at the larval and/or adult stage include Oberea erythrocephala (root feeder), Hyles euphorbiae (defoliator), and Chamaesphecia sp. (root feeder), all specific to Euphorbia species. We collected large numbers of adults of O. erythrocephala in 2004, and this particular species was evaluated in open field and laboratory conditions in 2005. In addition, the larval infestation rate was estimated during the winter to know the natural infestation of O. erythrocephala in the plots surveyed; the natural infestation rate ranged from 12 to 26%.
French cooperator : Laurence Curtet (ONCFS).
Le Maguet, J 2005. Caractérisation et évaluation des auxiliaires indigènes sur l'euphorbe ésule en vue d'une lutte biologique en Val de Saône. Mémoire de L'ENIHP. 52p+annexes.
Curtet L, Maudet F and R. Sforza 2005. First survey for biocontrol agents against the native but invasive Euphorbia esula in Saône valley (France). XIIIth European Weed Research Symposium, 19-24 June 2005, Bari (Italy)