1. International Institute of Tropical Agriculture (IITA), Ibadan 200001, Nigeria
2. Nematology Research Unit, Department of Biology, Ghent University, 9000 Ghent, Belgium
3. IITA, Kampala 7878, Uganda
4. Laboratory of Tropical Crop Improvement, Department of Biosystems, KU, Leuven, Belgium
5. IITA, Ibadan 200001, Nigeria