1. International Institute of Tropical Agriculture (UK) Limited; Carolyn House, 26 Dingwall Rd. Croydon CR9 3EE UK
2. Dep. of Crop Production and Protection; Obafemi Awolowo Univ.; Ile-Ife Nigeria
3. Institut National de Recherches Agricoles du Bénin; Cotonou Bénin
4. CRI-CSIR; Box 3785 Kumasi Ghana
5. CSIR-SARI; Box 52 Tamale Ghana
6. IAR, Ahmadu Bello Univ.; Samaru Nigeria