1. Department of Botany; Faculty of Science; University of Khartoum; PO Box 321 11115 Khartoum Sudan
2. Consiglio per la ricerca e la sperimentazione in agricoltura, Plant Pathology Research Centre; Via C.G. Bertero 22 Rome Italy
3. Dipartimento di gestione dei sistemi agricoli e forestali; ‘Mediterranea'University of Reggio Calabria; Località Feo di Vito, 89122 Reggio Calabria Italy
4. Agricultural Research Corporation; Shambat Agricultural Research Station; PO Box 30, 1111 North Khartoum Sudan