Dr R.J. Pretorius
Dr Rudolph Pretorius

POSITION
Lecturer
QUALIFICATIONS
N. Dip.: Agricultural Management (Technikon, Free State), B. Tech.: Agricultural Management (Central University of Technology, Free State), M. Tech.: Agriculture (Central University of Technology, Free State), Ph.D.: Entomology (University of Nebraska-Lincoln)
SHORT CV
Johan Pretorius is a lecturer for a variety of subjects to first, second and fourth year students within the Department of Agriculture, Central University of Technology. In addition to his lecturing activities, he is also involved in the supervision of postgraduate students. He completed his academic training in Agricultural Management at the Central University of Technology, Free State, where he obtained his N. Dip., B. Tech. and M. Tech. degrees, all with distinction. For the latter, he was awarded the Bronze Medal by the South African Association for the Advancement of Science (S2A3), as well as the Vice-Chancellor’s Award for the best postgraduate performance at the CUT. During his Masters’, Johan also completed occasional studies in entomology at the University of the Free State, where he was recognized by the Kovsie Alumni Trust as the best performing undergraduate student in the Faculty of Natural and Agricultural Sciences. Subsequently, he received a Fulbright Scholarship to pursue a Ph.D. in entomology at the University of Nebraska-Lincoln.
AREAS OF EXPERTISE
Agricultural Entomology, Entomology, Insect Identification, Agricultural Soil Science, Crop Production
PUBLICATIONS
Pretorius, R.J., Louw, S. vdM. & Venter, P. 2010. New record of Aphididae (Hemiptera) and Coccinellidae (Coleoptera) species associated with shadehouse-cultivated lettuce on a South African Highveld farm. African Entomology 18(2): 365-368.
Pretorius, R.J., Louw, S. vdM., Venter, P. & Van der Westhuizen, C. 2012. The impact of varying aphid populations in different shadehouse structures on some physical characteristics of head lettuce, cultivated in the central Free State (South Africa). Journal for New Generation Sciences 10(1): 116-129.
Pretorius, R.J., Hein, G.L. & Bradshaw, J.D. 2016. Ecology and management of Pemphigus betae (Hemiptera: Aphididae) in sugar beet. Journal of Integrated Pest Management 7(1): 10: 1-9. DOI: 10.1093/jipm/pmw008
Pretorius, R.J., Hein, G.L., Blankenship, E.E., Purrington, F.F. & Bradshaw, J.D. 2017. Response of Pemphigus betae (Hemiptera: Aphididae) and beneficial epigeal arthropod communities to sugar beet plant density and seed-applied insecticide in western Nebraska. Environmental Entomology 46(1): 107-117.  DOI 10.1093/ee/nvw157 
Pretorius, R.J., Hein, G.L., Blankenship, E.E., Purington, F.F., Wilson, R.G. & Bradshaw, J.D. 2018. Comparing the effects of two tillage operations on beneficial epigeal arthropod communities and their associated ecosystem services in sugar beets. Journal of Economic Entomology 111(6): 2617-2631. DOI 10.1093/jee/toy285 
Khetsha, Z.P., Sedibe, M.M. & Pretorius, R.J. 2020. Effects of abscisic acid and methyl jasmonate on the recovery of hail damaged rose geranium (Pelargonium graveolens) plants. Acta Hortic. 1278: 31-40. DOI: 10.17660/ActaHortic.2020.1287.5
Staude, H.S., Maclean, M., Mecenero, S., Pretorius, R.J., Oberprieler, R.G., Van Noort, S., Sharp, A., Sharp, I., Balona, J., Bradley, S., Brink, M., Morton, A.S., Botha, M.J., Collins, S.C., Grobler, Q., Edge, D.A., Williams, M.C. & Sihvonen, P. 2020. An overview of Lepidoptera-host-parasitoid associations for southern Africa, including an illustrated report on 2 370 African Lepidoptera-host and 119 parasitoid-Lepidoptera associations. Metamorphosis 31(3): 1-380.
Khetsha, Z.P., Sedibe, M.M., Pretorius, R.J. & Van der Watt, E. 2021. Cytokinin, gibberellic acid and defoliation on density and morphology of trichome of Pelargonium graveolens L’Hér for essential oil biosynthesis. Agrociencia 55(4): 331-346. DOI: https://doi.org/10.47163/agrociencia.v55i4.2481
Khetsha, Z.P., Sedibe M.M., Pretorius, R.J. & Van der Watt, E. 2021. Plant growth regulators and simulated hail damage improve rose-geranium (Pelargonium graveolens L’Hér.) leaf mineral status and phenolic composition. Applied Ecology and Environmental Research 19(4): 3083-3095. DOI: http://dx.doi.org/10.15666/aeer/1904_30833095
PRESENTED CONFERENCES, SEMINARS, WORKSHOPS
Conferences:
Pretorius, R.J., Louw, S. vdM. & Venter, P. 2008. Occurrence and seasonality of Aphididae and Coccinellidae species associated with lettuce cultivated under variable shade house conditions in the central Free State (South Africa). 23rd International Congress of Entomology, Durban, South Africa, 6-12 July. Poster Presentation.
Pretorius, R.J., Louw, S. vdM. & Venter, P. 2009. Seasonal fluctuations in aphid and coccinellid populations on shade house cultivated lettuce. 16th Annual congress of the Entomological Society of Southern Africa, Stellenbosch, South Africa, 5-7 July. Oral Presentation.
  • Pretorius, R.J., Bradshaw, J.D. & Hein, G.L. 2011. The impact of sugar beet variety and tillage management on the root aphid, Pemphigus betae, and its predators. 2011 North Central Branch Meeting - ESA, Minneapolis, Minnesota, United States of America, 13-16 March. Poster Presentation.
  • Pretorius, R.J., Bradshaw, J.D. & Hein, G.L. 2011. The impact of host plant resistance and tillage management on the sugar beet root aphid, Pemphigus betae (Doane), and its potential terrestrial predators. 59th Annual Meeting of the Entomological Society of America, Reno, Nevada, United States of America, 13-16 November. Poster Presentation.
  • Pretorius, R.J., Bradshaw, J.D. & Hein, G.L. 2012. Evaluating selected yield parameters of glyphosate tolerant sugar beet varieties subjected to sugar beet root aphid (Pemphigus betae Doane) infestations. 2012 North Central Branch Meeting - ESA, Lincoln, Nebraska, United States of America, 3-6 June. Oral Presentation.
  • Pretorius, R.J., Bradshaw, J.D. & Hein, G.L. 2012. The impact of tillage in sugar beet fields on the seasonal abundance of carabids (Coleoptera: Carabidae) in Western Nebraska. 60th Annual Meeting of the Entomological Society of America, Knoxville, Tennessee, United States of America, 11-14 November. Oral Presentation.
  • Pretorius, R.J., Bradshaw, J.D. & Hein, G.L. 2013. Seasonal fluctuations in beneficial arthropod complex associated with conventional tilled and zone tilled sugar beets. 37th Biennial Meeting of the American Society of Sugar Beet Technologists, Anaheim, California, United States of America, 27 February – 03 March. Oral Presentation.
  • Pretorius, R.J., Bradshaw, J.D. & Hein, G.L. 2013. The influence of tillage on beneficial, edaphic insect communities in sugar beets in western Nebraska. 2013 North Central Branch Meeting - ESA, Rapid City, South Dakota, United States of America, 16-19 June. Poster Presentation.
  • Pretorius, R.J., Bradshaw, J.D. & Hein, G.L. 2014. The influence of tillage in sugar beets on beneficial, edaphic arthropod communities, and the arthropod-mediated ecosystem services they provide. 2014 North Central Branch Meeting - ESA, Des Moines, Iowa, United States of America, 9-12 March. Oral Presentation.
  • Bradshaw, J.D. & Pretorius, R.J. 2014. The conservation of edaphic biological control. 62nd Annual Meeting of the Entomological Society of America, Portland, Oregon, United States of America, 16-19 November. Oral Presentation.
  • Pretorius, R.J., Bradshaw, J.D. & Hein, G.L. 2015. The provision of ecosystem services by beneficial arthropods in agroecosystems. 19th Annual congress of the Entomological Society of Southern Africa, Grahamstown, South Africa, 12-17 July. Oral Presentation.
  • Bradshaw, J.D. & Pretorius, R.J. 2015. The conservation of edaphic biological control. 2nd Annual Wyoming-Nebraska Organic Farming Conference, Torrington, Wyoming, United States of America, 10 February. Oral Presentation.
  • Pretorius, R.J., Bradshaw, J.D. & Hein, G.L. 2016. Ecologically-based pest management on the US central High Plains: Structuring a better environment for conservation biology to work in sugar beet. 25th International Congress of Entomology, Orlando, Florida, United States of America, 25-30 September. Oral Presentation.
  • Khetsha, Z.P., Sedibe, M.M. & Pretorius, R.J.  2018. Effects of abscisic acid and methyl jasmonate on the recovery of hail-damaged rose geranium (Pelargonium graveolens L.) plants. 30th International Horticultural Congress, Istanbul Turkey, 12 – 16 August.
  • Staude, H., Maclean, M., Sharp, A., Mecenero, S., Pretorius, R.J., Edge, D., Sharp, I., Van Noort, S. & Oberprieler, R. 2019. Building a database of Lepidoptera-host-parasitoid associations recorded for the Afrotropical region. Joint Biodiversity Information Management & Foundational Biodiversity Information Programme, Roodevalley Faircity Hotel, Pretoria, South Africa, 20-22 August 2019. Oral Presentation. 
  • Pretorius, R.J. 2020. South African agriculture: Research & technologies. Panhandle Agricultural Research and Technology Tour (PARTT+), Scottsbluff, Nebraska, United States of America, 20 August 2020. Online oral Presentation – Keynote Speaker.
Seminars:
•      Pretorius, R.J. Carabids (Coleoptera: Carabidae) as Natural Enemies of Pests and Weeds in Agro-ecosystems. Public seminar, Lincoln, Nebraska, USA, 21 February 2012.
•     Pretorius, R.J. Entomopathogenic Nematodes for Biological Control with Emphasis on Controlling Above-Soil Pests. Public seminar, Lincoln, Nebraska, USA, 19 February 2013.
•     Pretorius, R.J. The sugar beet root aphid (Pemphigus betae Doane) as a pest of sugar beet: considering management options for a subterranean pest. Public seminar, Lincoln, Nebraska, USA, 27 August 2011.
•     What you weren’t told about bugs insects. Presented to the Scotts Bluff County Homemakers Club, Gering Public Library, Nebraska, USA, 28 February 2014.
•     What you weren’t told about bugs insects. Presented to the Wildcat Audubon Chapter, Regional West Medical Center, Nebraska, USA, 18 October 2014.
•      Insekte: Diversiteit en belang vir die mens. Presented to the general public of Hoopstad, Hoopstad Huis vir Bejaardes, Hoopstad, Free State, South Africa, 09 October 2015.
Workshops:
  • Research on sugar beet-associated pests and their natural enemies Presented to farmers in Western Nebraska, PHREC, Scottsbluff, 2011.
  • Soil-dwelling predators in sugar beet fields with emphasis on ground beetles (Coleoptera: Carabidae). Presented to farmers in Western Nebraska, PHREC, Scottsbluff, 2012.
General introduction to the insect orders and their
development. Presented to Clinvet personnel, Clinvet, Bainsvlei, Bloemfontein, Free State, South Africa, 14 October
2016.
General introduction to the insect orders and their development. Presented to the Clinvet personnel, Clinvet, Bainsvlei, Bloemfontein, Free State, South Africa, 14 October 2016.
Pretorius, R.J. 2016 & 2019. The basics of statistics and data analysis. Prosperitas auditorium, Central University of Technology, Free State. Agricultural Research Day, 26 May.
Pretorius, R.J. 2016 & 2019. Preparing oral presentations and posters for conferences. Prosperitas auditorium, Central University of Technology, Free State. Agricultural Research Day, 26 May 2016.
EXTERNAL PROFILES
LinkedIn
ResearchGate

Contact Us
  • Dr Rudolph Pretorius
  • Tel: +27 (0)51 507 4076
  • rjpretor@cut.ac.za