Prof. Julie Coetzee

Aquatic Weeds Programme Manager

Julie profile

Julie completed her PhD at the University of the Witswatersrand in 2003. Currently her research focuses on the biological control of invasive aquatic plants. She started working on biological control agents of water hyacinth in 1998, and has never looked back. Recently she has shifted the focus of her work on floating aquatic plants to submerged and emergent aquatic plants. As we have gained excellent control of the floating species, this new suite of species has taken advantage of these new habitats, threatening indigenous aquatic flora and fauna. Tackling these new problem plants is a challenge, but we will benefit from experience gained elsewhere in controlling these species, as well as pioneering new methods of control for South Africa.

Julie is the President of the Entomological Society of Southern Africa -

Research interests

  • Biological control of weeds
  • Plant-insect interactions
  • Invasion biology
  • Insect thermal ecology
  • Aquatic plant ecology
  • Biostatistics

Recent Publications

1. Coetzee, J.A. and Hill, M.P. 2020. Salvinia molestaMitch. (Salviniaceae): impact and control. CAB Reviews 15, No. 033. 1-11. doi: 10.1079/PAVSNNR202015033

2. Coetzee, J.A., Langa, S.D.F., Motitsoe, S.N. and Hill, M.P. 2020. Biological control of water lettuce, Pistia stratiotes, facilitates macroinvertebrate biodiversity recovery: a mesocosm study. Hydrobiologia 847:3917–3929.

3. Gervazoni, P., Sosa, A., Franceschini, C., Coetzee, J.A., Faltlhauser, A., Fuentes-Rodriguez, D., Martínez, A. and Hill, M.P. 2020. The alien invasive yellow flag (Iris pseudacorus) in Argentinian wetlands: assessing geographical distribution through different data sources. Biological Invasions 22:3183–3193.

4. Hofstra, D., Schoelynck, J., Ferrell, J., Coetzee, J., de Winton, M., Bickel, T.O., Champion, P., Madsen, J., Bakker, E.S., Hilt, S. and Matheson, F. 2020. On the move: New insights on the ecology and management of native and alien macrophytes. Aquatic Botany 162:

5. Miller, B.E.; Coetzee, J.A.; Hill, M.P. 2020. Mind the gap: the delayed recovery of a population of the biological control agent Megamelus scutellaris  (Hemiptera: Delphacidae) on water hyacinth after winter. Bulletin of Entomological Research 111: 120 – 128 DOI:

6. Motitsoe, S.N., Coetzee, J.A., Hill, J.M. and Hill, M.P. 2020. Biological control of Salvinia molesta (D.S. Mitchell) drives aquatic ecosystem recovery. Diversity 12: 204.

7. Muskett PC, Paterson ID, Coetzee JA (2020) Ground-truthing climate-matching predictions in a post-release evaluation. Biological Control 144: 104217.

8. Ndlovu, M.S., Coetzee, J.A., Nxumalo, M.M., Lalla, R & Shabalala, N., Martin, G.D., The Establishment and Rapid Spread of Sagittaria platyphylla in South Africa. Water 12(5):1472

9. Reid, M.K., Coetzee, J.A., Hill, M.P., Diaz, R., Gettys, L.A., Cuda, J.P. and Reid, C.S. 2020. Insect herbivores associated with Nymphaea mexicana in southern United States: Potential biological control agents for South Africa. Florida Entomologist 103: 54-63.

10. Minuti, G., Coetzee, J.A., Stiers, I., Ngxande-Kota, S., & Hill, M.P. 2021. Prospects for the biological control of Iris pseudacorus (Iridaceae). Biocontrol Science and Technology, 31:3, 314-335.

11. Baso, N., Coetzee, J.A., Ripley, B.S. & Hill, M.P. 2021. The effects of elevated atmospheric CO2 concentration on the biological control of invasive aquatic weeds. Aquatic Botany 170: 103348.

12. Harms, N.E., Knight, I.A., Pratt, P.D., Reddy, A.M., Mukherjee, A., Gong, P., Coetzee, J., Raghu, S. and Diaz, R., 2021. Climate Mismatch Between Introduced Biological Control Agents and Their Invasive Host Plants: Improving Biological Control of Tropical Weeds in Temperate Regions. Insects, 12(6), p.549.

13. Hussner, A., Heidbüchel, P., Coetzee, J. and Gross, E.M., 2021. From introduction to nuisance growth: a review of traits of alien aquatic plants which contribute to their invasiveness. Hydrobiologia, pp.1-33.

14. Reid, M.K., Naidu, P., Paterson, I.D., Mangan, R. and Coetzee, J.A., 2021. Population genetics of invasive and native Nymphaea mexicana Zuccarini: Taking the first steps to initiate a biological control programme in South Africa. Aquatic Botany, 171, p.103372.

15. van Noort, S., Smith, R. and Coetzee, J.A., 2021. Identity of parasitoid wasps (Hymenoptera, Braconidae and Eulophidae) reared from aquatic leaf-mining flies (Diptera, Ephydridae) on invasive Brazilian waterweed Egeria densa in South Africa. African Invertebrates, 62, p.287. doi:10.3897/AfrInvertebr.62.62842

16. Maseko, Z., Coetzee, J.A. and Hill, M.P., 2021. Population dynamics of the biological control agent, Eccritotarsus catarinensis Carvalho (Miridae) on Pontederia crassipes Pellegrini and Horn (Pontederiaceae) at a cool temperate site in South Africa. African Entomology, 29(1), pp.307-310.

17. Smith, R., Coetzee, J.A. and Hill, M.P. Accepted. Best of both worlds: The thermal physiology of Hydrellia egeriae, a biological control agent for the submerged aquatic weed, Egeria densa in South Africa. BioControl.

18. Olckers, T., Coetzee, J.A., Egli, D. Martin, G.D., Paterson, I.D., Sutton, G.F. & Wood, A.R. 2021. Biological control of South African plants that are invasive elsewhere in the world: A review of earlier and current programmes. African Entomology in press.

19. Hill, M.P., Conlong, D., Zachariades, C., Coetzee, J.A., Paterson, I.D., Miller, B.E., Foxcroft, L., and van der Westhuizen, L. 2021. The role of mass-rearing in weed biological control projects in South Africa. African Entomology in press.

20. Coetzee, J.A., Bownes, A., Martin, G.D., Miller, B.E., Smith, R., Weyl, P.S.R. and Hill, M.P. Accepted. A review of the biological control programmes against aquatic weeds in South Africa. African Entomology.


Last Modified: Wed, 28 Jul 2021 15:43:20 SAST