1. Plant Health Diagnostic Services, Department of Agriculture, Forestry and Fisheries (DAFF), Private Bag X5015, Stellenbosch, 7599 South Africa
2. Unit for Environmental Sciences and Management, Potchefstroom Campus, North-West University, Private Bag X6001, Potchefstroom, 2520 South Africa
3. National Plant and Plant Product Inspection Services, Department of Agriculture, Forestry and Fisheries (DAFF), Private Bag X5015, Stellenbosch, 7599 South Africa