1. Du Roi Laboratory, Letsitele, 0885, South Africa
2. ARC-Plant Protection Research Institute, Queenswood, 0121, South Africa
3. Department of Microbiology and Plant Pathology, University of Pretoria, 0002, South Africa
4. Citrus Research International, c/o Department of Microbiology and Plant Pathology, University of Pretoria, 0002, South Africa