Category: Biological pest control
Groupe de Recherche en Agriculture Biologique
Maison de la Bio – Agroparc – BP 1222
F 84 911 – AVIGNON Cedex 9 – FRANCE
Tel : +33 490 840 170
Mobile : +33 682 909495
Email : firstname.lastname@example.org
Olive fruit fly remains the most damaging pest, with significant yearly damages on fruits and olive oil quality. Although several parasitoids are known, biocontrol levels are usually low, below 4%. Landscape has been intensively simplified in the last decades, leading to biodiversity erosion, and loss of trophic relations. Literature however shows interactions between olive tree and other mediterranean species, hosting beneficial insects on alternative phytophagous species.
By sawing or planting Dittrichia viscosa, we intend to increase the population of phytophagous diptera (Myopites stylata), and in a second time of the larval parasitoid Eupelmus urozonus.
A questionnaire will be submitted to growers using D. viscosa, in order to better estimate how the plant is developing, and if Myopites galls can be observed.
Lactuca viminea is also suspected as an interesting host plant, and will be set up in some orchards if seeds can be easily found.
In a second time, augmentoria (emergence cages) will be set up in orchards, allowing micro-hymenoptera to emerge, but keeping olive flies inside.
- Gérard Delvare, CIRAD Montpellier,
- Nicolas Ris, INRA Sophia-Antipolis
- Edy Spagnol, Claude Conand, Bruno Theuerlacher, organic olive growers
Surveys in orchards where Dittrichia has been set up will give additional information about its development and requirements. The presence of galls is determinant for the establishment of the tritrophic relation, therefore it has to be linked to the use of insecticides on the plot.
Visible results on the introduction of useful plants in olive groves should help the growers to reconsider biodiversity and not try to get rid of all weeds. The supposed increase of parasitism in olives will convince them to reduce insecticidal sprays, and use agroecology as a tool.