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 CITRUS PATHOLOGY PROGRAMME

Current position: Programme Manager of Preharvest Disease Research

Citrus Research International

In my position at CRI, I am responsible for coordinating research in the Preharvest disease programme, conducting research in the field of citrus fruit and foliar diseases, publication of research results in accredited journals and for ensuring technology transfer and reports of all research projects to the citrus industry in South Africa.

Selected publications:

Theron, E., Bophela, K.N., Bisschoff, J., Shin, G., Coutinho, T.A., van der Waals, J.E. 2023. Survey of Soft Rot Pectobacteriaceae Infecting Potatoes in South Africa. Potato Research 66: 723-749 https://doi.org/10.1007/s11540-022-09598-1

Takooree, S.D., Neetoo, H., Ranghoo-Sanmukhiya, V.M., Hardowar, S., van der Waals, J.E., Vally, V., Bunwaree, A.G., Vojvodic, M., and Bulajic, A. 2021. First report of Black Scurf caused by Rhizoctonia solani AG-3 on potato tubers in Mauritius. Plant Disease 105:213.

Mushonga, K., Steyn, J.M., Swart, W.J., van der Waals, J.E. 2020. Plant-soil feedback responses of four dryland crop species under greenhouse conditions. Plant Environment Interactions https://doi.org/10.1002/pei3.10035

Muzhinji, N., Dube, J.P., De Haan, E.G., Woodhall, J.W., van der Waals, J.E. 2020. Development of a TaqMan PCR assay for specific detection and quantification of Pectobacterium brasiliense in potato tubers and soil. European Journal of Plant Pathology 158(2): 521-532.

van der Waals, J.E., Kruger, K. 2020. Emerging potato pathogens affecting food security in southern Africa:Recent research. South African Journal of Science 116(11-12): 1-7.

Kruger, K., van der Waals, J.E. 2020. Potato virus Y and Potato leafroll virus management under climate change in sub-Saharan Africa. South African Journal of Science 116(11-12): 1-7.

Lekota, M., Modisane, K.J., Apostolides, Z., van der Waals, J.E. 2020. Metabolomic fingerprinting of potato cultivars differing in susceptibility to Spongospora subterranea f. sp. subterranea root infection. International Journal of Molecular Sciences 21, 3788; doi:10.3390/ijms21113788

Simango, K., Slabbert, C., van der Waals, J.E. 2020. Alternative hosts of Spongospora subterranea f. sp. subterranea in southern Africa. European Journal of Plant Pathology 157(2): 421-424  https://doi.org/10.1007/s10658-020-01993-z

Mbedzi, P.P., Van der Hoven, L., Vorster, B.J., van der Waals, J.E. 2019. Screening for Sclerotinia sclerotiorum resistance using detached leaf assays and simple sequence repeat markers in soybean cultivars. Crop Protection 125:104909.

Muzhinji, N., van der Waals, J.E. 2019. Population biology and genetic variation of Spongospora subterranea f. sp. subterranea, the causal pathogen of powdery scab and root galls on potatoes in South Africa. Phytopathology 109(11): 1957-1965 https://doi.org/10.1094/PHYTO-12-18-0467-R

Jordaan, E., McLaren, N.W., van der Waals, J.E. 2019. Effect of irrigation on charcoal rot severity, yield loss and colonization of soybean and sunflower. Crop Protection 122: 63-69 doi.org/10.1016/j.cropro.2019.04.026

Lekota, M., Muzhinji, N., van der Waals, J.E. 2019. Identification of differentially expressed genes in tolerant and susceptible potato cultivars in response to Spongospora subterranea f. sp. subterranea tuber infection. Plant Pathology 68:1196-1206 doi: 10.1111/ppa.13029

Dube, J.P., Valverde, A., Steyn. J.M., Cowan, D., van der Waals, J.E. 2019. Differences in bacterial diversity, composition and function due to long-term agriculture in soils in the Eastern Free State of South Africa. Diversity 11, 61; doi:10.3390/d11040061

Gush, S.-L., Muzhinji, M., Truter, M., & van der Waals, J.E. 2019. First report of Rhizoctonia solani AG 2-2IIIB causing elephant hide on potato tubers in South Africa. Plant Disease, 103(7): 1776, https://doi.org/10.1094/PDIS-10-18-1850-PDN

Kandolo, S.D., Aveling, T.A.S., van der Waals, J.E., Truter, M. & Laurie, S.M. 2018. Effects of wetness duration, inoculum concentration and temperature on the development of Alternaria blight on transplants of sweet potato. Acta Horticulturae 27: 211–217.

Zimudzi, J., van der Waals, J.E., Coutinho, T.A., Cowan, D.A. & Valverde, A. 2018. Temporal shifts of fungal communities in the rhizosphere and on tubers in potato fields. Fungal Biology122: 928-934.

Muzhinji, M., Woodhall, J.W., Truter, M. & van der Waals, J.E. 2018. Variation in fungicide sensitivity among Rhizoctonia isolates recovered from potatoes in South Africa. Plant Disease  102(8): 1520-1526.

Shutt, V.M., Shin, G., van der Waals, J.E., Goszczynska, T. & Coutinho, T.A. 2018. Characterization of Ralstonia strains infecting tomato plants in South Africa. Crop Protection 112: 56-62.

Muzhinji, M., Woodhall, J.W., Truter, M. & van der Waals, J.E. 2018. Relative contribution of seed tuber- and soilborne inoculum to potato disease development and changes in the population genetic structure of Rhizoctonia solani AG 3-PT under field conditions in South Africa. Plant Disease 102(1): 60-66.

Zimudzi, J. Coutinho, T.A. & van der Waals, J.E. 2017. Pathogenicity of fungi isolated from atypical skin blemishes on potatoes in South Africa and Zimbabwe. Potato Research 60: 119-144.

Simango, K. & van der Waals, J.E. 2017. Effects of different soil treatments on the development of Spongospora subterranea f. sp. subterranea in potato roots and tubers in the greenhouse. Potato Research 60:47-60

Muzhinji, M., Woodhall, J.W., Truter, M. & van der Waals, J.E. 2016. Population genetic structure of Rhizoctonia solani AG 3-PT from potatoes in South Africa. Fungal Biology 120: 701-710.

Van der Waals, J.E., Steyn, J.M., Franke, A.C., Haverkort, A.J. 2016. Grower perceptions of biotic and abiotic risks of potato production in South Africa. Crop Protection 84: 44-55

Jordaan, E. & van der Waals, J.E. 2016. Streptomyces species associated with common scab lesions of potatoes in South Africa. European Journal of Plant Pathology 144: 631 - 643.

Du Raan, S., Coutinho, T.A. & van der Waals, J.E. 2016. Cardinal temperature differences, determined in vitro, between closely related species and subspecies of pectinolytic bacteria responsible for blackleg and soft rot on potatoes. European Journal of Plant Pathology 144: 361 - 369.

Muzhinji, M., Woodhall, J.W., Truter, M. & van der Waals, J.E. 2015. Anastomosis groups and pathogenicity of Rhizoctonia solani and binucleate Rhizoctonia from potatoes in South Africa. Plant Disease 99: 1790 - 1802.

Van der Waals, J.E., Franke, A.C., Haverkort, A.J., Krüger, K. & Steyn, J.M. 2013. Climate change and potato production in South Africa. 3. Effects on relative development rates of selected pests and pathogens. Potato Research 56: 67-84

Wright, J., Lees, A.K., van der Waals, J.E. 2012. Detection and eradication of Spongospora subterranea f. sp. subterraneain mini-tuber production tunnels. South African Journal of Science, 108 (5/6) Art #614

Van der Merwe, J.J., Coutinho, T.A., Korsten, L. & van der Waals, J.E. 2010. Pectobacterium carotovorum subsp. brasiliensis causing blackleg on potatoes in South Africa. European Journal of Plant Pathology 126 (2): 175-185.