The primary research focus of the Potato Pathology Programme is the epidemiology, diagnosis and control of soil- and seed-borne diseases of potatoes. Diseases currently being investigated in this research programme include powdery scab (Spongospora subterranea f. sp. subterranea), black scurf and stem canker (Rhizoctonia solani), and blackleg and soft rot (Pectobacterium and Dickeya spp.). Soil and seed-borne pathogens are among the most limiting factors in the production of potatoes and thus the main focus of the Potato Pathology Programme @ UP is understanding these pathogens and epidemiology of the diseases in order to improve management in the field. In order to do this, various techniques are combined to better understand disease spread and development in the field, interaction of host and pathogen, and ultimately use this information to provide growers with a risk assessment for the disease under consideration. 

New Publications

Alabi G, Maharaj V, Van der Waals JE, Invernizzi L, Coutinho T. (2026) Managing Brown Rot Disease of Citrus Fruit Using Plant Extracts. Journal of Phytopathology 174:e70254. 10.1111/jph.70254 PDF
Cruywagen E, Sutherland R, Nkosi B, Van der Waals JE, Truter M. (2026) Multiple large and small-spored Alternaria species causing leaf spot of potato in South Africa. Journal of Plant Pathology 108:1299-1305. 10.1007/s42161-025-02082-y PDF
Theron E, Van Niekerk J, Van der Waals JE. (2026) In vitro phosphonate sensitivity of South African citrus Phytophthora nicotianae isolates. Acta Horticulturae 1448(69):549-556. 10.17660/ActaHortic.2026.1448.69
Theron E, van Niekerk JM, van der Waals JE. (2025) A review of the use of phosphonates in the management of Phytophthora nicotianae in citrus in South Africa. Phytoparasitica 53(11) 10.1007/s12600-024-01234-7 PDF
Liakos C, Cowan D, Kvitko B, Dutta B, du Toit L, van der Waals JE, Derie ML, Lebre P, Ibanez V, Coutinho TA. (2024) The Bacterial and Viral Communities Associated with OnionBacterial Bulb Rot. Phytobiomes Journal 10.1094/PBIOMES-11-23-0121-R PDF