1. Faculté des Sciences Agronomiques, Université d’Abomey-Calavi, 01 BP 526 Cotonou, Benin
2. Technology and Agrarian Development Group, Wageningen University, Wageningen, The Netherlands
3. Crop and Weed Ecology Group, Wageningen University, Wageningen, The Netherlands
4. 06 BP 2083 Cotonou, Benin