INRA, Agrocampus Rennes, UMR 1099 BiO3P (Biology of Organisms and Populations applied to Plant Protection), F-35653 LE RHEU, France. jean-pierre.gauthier@rennes.infra.fr|INRA, Agrocampus Rennes, UMR 1099 BiO3P (Biology of Organisms and Populations applied to Plant Protection), F-35653 LE RHEU, France. jean-pierre.gauthier@rennes.infra.fr|INRA, Agrocampus Rennes, UMR 1099 BiO3P (Biology of Organisms and Populations applied to Plant Protection), F-35653 LE RHEU, France. jean-pierre.gauthier@rennes.infra.fr|INRA, Agrocampus Rennes, UMR 1099 BiO3P (Biology of Organisms and Populations applied to Plant Protection), F-35653 LE RHEU, France. jean-pierre.gauthier@rennes.infra.fr|INRA, Agrocampus Rennes, UMR 1099 BiO3P (Biology of Organisms and Populations applied to Plant Protection), F-35653 LE RHEU, France. jean-pierre.gauthier@rennes.infra.fr