Dr Gert Marais
Senior Lecturer
Plant Sciences
Plant Science
IB 64
Biology Building

Short CV

Gert J. Marais obtained a B.Sc. (Microbiology & Botany, 1989), BSc Honours (Microbiology, 1990), and a PhD (Mycology, 1996) at the University of the Free State.  In 1994 he started working as a scientist in the Chemical and Microbial Products Programme at CSIR Foodtek.  In 1996 he became a project leader and in 1998 he moved to the Food Quality Programme at the CSIR.  He was appointed as a specialist scientist in 1999 and started working in 2000 in the Process Biotechnology Programme at CSIR Bio/Chemtek.  In 2001 he was seconded to the University of Pretoria and headed and established the Centre for Applied Mycological Studies in 2004.  During 2006 and 2008, Gert Marais was appointed as a national consultant for the FAO in advising the Departments of Health and Agriculture on mycotoxins.  In 2010, he moved with his family to Bloemfontein and started working at the University of the Free State as a senior lecturer in the Plant Sciences department.  In 2017 the Pecan Health Research Group was established in collaboration with the South African Pecan Nut Producers Association (SAPPA), which is headed by him.  The research group is focussing on pecan diseases and optimising the health of pecans in South Africa.


Achilonu, C.C., M. Gryzenhout, G.J. Marais, T.T. Madisha, and Soumya Ghosh. 2023. Random amplified microsatellites (RAMS) analysis ascertains genetic variation of Alternaria alternata causing black spot disease on Carya illinoinensis in South Africa. Frontiers in Genetics 14: 1-11.

Marais, G.J. & C.C. Achilonu. 2023. Alternaria Black Spot in South African pecans. SA Pecan 95: 10-14.

Achilonu, C.C., M. Gryzenhout, S. Ghosh, and G.J. Marais. 2023. In vitro evaluation of azoxystrobin, boscalid, fentin-hydroxide, propiconazole, pyraclostrobin fungicides against Alternaria alternata pathogen isolated from Carya illinoinensis in South Africa. Microorganisms 11: 1691-1704.

Achilonu, C.C., M. Gryzenhout, G.J. Marais, and S. Ghosh. 2023. Differential detection of Alternaria alternata haplotypes isolated from Carya illinoinensis using PCR-RFLP analysis of Alt a1 gene region. Genes 14: 1115-1129.

Marais, G.J. 2023. Macro-fungi associated with pecan orchards in South Africa. SA Pecan 94: 8-11.

Achilonu, C.C., G.J. Marais, S. Ghosh and M. Gryzenhout. 2023. Multigene phylogeny and pathogenicity trials revealed Alternaria alternata as the causal agent of black spot disease and seedling wilt of pecan (Carya illinoinensis) in South Africa. Pathogens 12: 672-691.

Tembo, E., A. Minnaar-Ontong, A. Menkir, G.J. Marais, C. Magorokosho & M.T. Labuschagne. 2022. Inheritance of resistance to Fusarium verticillioides ear rot in maize inbred lines of southern, West and Central Agrica origin. Crop Science 2022: 1-16. DOI: 10.1002/csc2.20776.

Marais, G.J. 2021. Managing diseases, pests and other problems: Diseases. In: Production guidelines for pecan. Eds. A.D. Sippel and H. du Toit. ARC-Tropical and Subtropical Crops. ISBN No 978-0-621-49137-1

Marais, G.J. 2021. Pecan diseases in South Africa. SA Pecan 88: 12-13.

Marais, G.J. 2020. Plant Pathogenic risks of pecan in South Africa. SA Pecan 85: 18-20. 

Greeff-Laubscher, M.R., I. Beukes, G.J. Marais & K. Jacobs. 2019. Mycotoxin production by three different toxigenic fungi genera on formulated abalone feed and the effect of an aquatic environment on fumonisins. Mycology DOI: 10.1080/21501203.2019.1604575 (ISSN 2150-1203).

Greeff-Laubscher, M.R., I. Beukes, G.J. Marais & K. Jacobs. 2018. The occurrence of mycotoxigenic fungi in abalone feed in South Africa. African Journal of Marine Science 40(4): 383-394. (ISSN 1814-2328).

Marais, G.J. 2018/2019. Pecan diseases and health risks in South Africa. SA Pecan 81: 22-24.

Vermeulen, M., S. vdM Louw, G.J. Marais, W.J. Weeks, W.J. Swart & M. Gryzenhout. 2018. Fungi associated with disease and weevil damage of Amaranthus cruentus in South Africa. African Entomology 26(1): 174-188. 

Marais, G.J. 2017/2018. Plant pathogenic risks associated with pecans in South Africa. SA Pecan 78: 34-35.

Lategan-Potgieter, R. & G.J. Marais. 2017. Health benefits of pecan nuts. SA Pecan 75: 25. 

Marais, G.J. 2017. Fungi associated with pecan diseases in South Africa. SA Pecan 75. 22-24.

Marais, G.J. 2016. Pecan diseases in South Africa. SA Pecan 73: 26-27.

Marais, G.J. 2015. Fungal diseases of pecans in South Africa. Spilpunt March/April: 16-17.

Slippers, B., J. Roux, M.J. Wingfield, F.J.J. van der Walt, F. Jami, J.W.M. Mehl & G.J. Marais 2014. Confronting the constraints of morphological taxonomy in the fungi: A Botryosphaeriaceae case study. Persoonia 33: 155-168. (Impact factor: 4.225) (ISSN 0031-5850)

Dawlal, P., E. Barros & G.J. Marais. 2012. Evaluation of maize cultivars for their susceptibility towards mycotoxigenic fungi under storage conditions. Journal of Stored Products Research, 48: 114-119.

Barros MEC, Crampton MC, Marais GJ & S Lezar. 2008. A DNA-based method to quantify Stenocarpella maydis in maize. Maydica, 53(2): 125-129. (Impact factor: 0.494)

Naicker, D., G.J. Marais, H. van den Berg & M.G. Masango. 2007. Some fungi, zearalenone and other mycotoxins in chicken rations, stock feedstuffs, lucerne and pasture grasses in the communal farming area of Rhenosterkop in South Africa. Journal of the South African Veterinary Association, 78(2): 69-74.

 Van der Walt, F.J.J., G.J. Marais and A. Lubben. 2007. Fungal biodiversity of indigenous trees and plants in the Northern Cape. South African Journal of Science 103(1-2): xiii-xiv.

Van der Nest, A., G.J. Marais and A. Lubben. 2007. Fungi and their mycotoxins associated with animal feed in South Africa. South African Journal of Science 103(1-2): xiv-xv.

Dawlal, P, G.J. Marais and A. Lubben. 2007. The effect of irradiation on mycotoxigenic fungi in commercially produced maize cultivars. South African Journal of Science 103(1-2): xvi.

Kvas, M., G.J. Marais, E.T. Steenkamp and A. Lubben. 2005. Mycotoxigenic fungi associated with commercial pet food. South African Journal of Science 101: xxiv.

Lefyedi, M.L., G.J. Marais, M.F. Dutton & J.R.N. Taylor. 2005. The microbial contamination, toxicity and quality of turned and unturned floor malted sorghum. Journal of the Institute of Brewing 111(2): 190-196.

Marais, G.J. & M.J. Wingfield. 2001. Ophiostoma africanum sp. nov., and a key to ophiostomatoid species from Protea infructescences. Mycological Research 105 (2): 240-246.

Marais, G.J. 2000. Fungi and mycotoxins in pig feed. Porcus 15 (6): 10-15.

Stander, M.A., P.S. Steyn, A. Lübben, A. Miljkovic, P.G. Mantle & G.J. Marais. 2000. Influence of halogen salts on the production of the ochratoxins by Aspergillus ochraceus Wilh. Journal of Agricultural and Food Chemistry 48 (5): 1865-1871.

Marais, G.J. April/May 2000. The effect of fungi and mycotoxins in humans and animals in the RSA. VETMED 13 (2): 13-17.

Marais, G.J. 2000. Fungi and mycotoxins in food and feed in the RSA. AFMA Matrix, March 2000, 27-29.

Marais, G.J., M.J. Wingfield, C.D. Viljoen & B.D. Wingfield. 1998. A new ophiostomatoid genus from Protea infructescences. Mycologia 90: 136-142.

Marais, G.J. 1997. Mycotoxins in poultry feed in South Africa. Poultry Bulletin August 1997, pp. 376-378.

Rabie, C.J., A. Lubben, G.J. Marais & H. Jansen van Vuuren. 1997. Enumeration of fungi in barley. International Journal of Food Microbiology 35: 117-127.

Marais, G.J. & M.J. Wingfield. 1997. Ophiostoma protearum sp. nov. associated with Protea caffra infructescences. Canadian Journal of Botany 75: 362-367.

Rabie, C., A. Lubben, G.J. Marais & H. Jansen van Vuuren. 1996. Evaluation of grain and grain products for toxigenic fungi and mycotoxins. pp. 32-37. In: Grain Quality Assessment Ed. P.G. Randall. Papers presented at the International Association of Cereal Science and Technology, Johannesburg.

Marais, G.J. & M.J. Wingfield. 1994. Fungi associated with infructescences of Protea species in South Africa, including a new species of Ophiostoma.


The main focus of current research is on identifying the major diseases associated with pecan production in South Africa and finding ways of managing them.  This include seasonal field trips to the major pecan producing areas in South Africa, including Limpopo, Mpumalanga, KZN, Eastern and Western Cape, Free State, and Northern Cape provinces with regular farmers days and feed back sessions to the industry. 

Area(s) of Interest

Areas of interest include:

Food mycology


Plant Pathology

Fungal metabolites and production

Courses Presented

PPLG2624 (Principals in Plant Pathology) - Fungal diseases, Bacterial diseases, Viral diseases, Abiotic stresses, Nematodes

PPLG3714 (Fungal diseases of plants) - semester course

MCBD6824 (Microbial diversity) - 5 day Mycology module for honours students

BLGY1643 (Biology) - 1 week Plant Pathology module for 1st year students



Elfrieda van den Berg (Marketing Manager)
T: +27 51 401 2531

Dilahlwane Mohono (Faculty Officer)
T: +27 58 718 5284

Home new

We use cookies to make interactions with our websites and services easy and meaningful, to better understand how they are used and to tailor advertising. You can read more and make your cookie choices here. By continuing to use this site you are giving us your consent to do this.