1. Department of Botany, Ahmadu Bello University, Zaria, Kaduna State, Nigeria
2. Department of Plant Pathology, University of California, Davis
3. Department of Crop Protection, Ahmadu Bello University, Zaria, Kaduna State, Nigeria
4. Department of Plant Pathology & Microbiology, Texas A&M AgriLife Research and Extension Center, Weslaco, TX 78596.