There are several significant pathogens and pests impacting avocado, such as Phytophthora root rot, White root rot,  and most recently, Fusarium Dieback, caused by the PSHB and its fungal symbiont Fusarium euwallaceae. The ARP at FABI offers a disease clinic to avocado growers for the identification of avocado diseases. A consultation fee will be charged accordingly.




How to sample?

  • Take a photo of the symptoms, if possible
  • Samples should be taken from 4-5 randomly selected plants in an infection site.
  • Place the samples separately in a paper bag (Never use a plastic bag!!)
  • Seal the bag and label with the following: Collectors name, date, sample number, locality and cultivar

Specific tissue sampling

  • Collect individual leaves, place between blotting paper (paper towel) and in an envelope
  • Collect a sample that spans the diseased area, including +/- 2cm of healthy tissue on either side of the lesion
  • Place in a paper bag
  • Collect 200g of soil from under the diseased tree at a depth of 10-15 cm, place in a paper bag
  • Collect root pieces (healthy and diseased) from the soil and place in an envelope


Online submission: ARP Disease diagnostic clinic:

Additional information regarding sample submission:


Information Sheets

 Phytophthora cinnamomi


Avocado Sunblotch Viroid

Send the samples by fast mail or courier to the Avocado Disease Clinic @ FABI and give us a phone call to let us know to expect a parcel from you.
Ms Jesse Hartley
Disease Clinic Manager
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Prof Noelani van den Berg

Group Leader

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74 Lunnon street
Avocado Research Programme
University of Pretoria
(012) 420 3177

New Publications

Wingfield BD, Berger DK, Coetzee MPA, Duong TA, Martin A, Pham NQ, Van den Berg N, Wilken PM, Arun-Chinnappa KS, Barnes I, Buthelezi S, Dahanayaka BA, Durán A, Engelbrecht J, Feurtey A, Fourie A, Fourie G, Hartley J, Kabwe ENK, Maphosa M, Narh Mensah DL, Nsibo DL, Potgieter L, Poudel B, Stukenbrock EH, Thomas C, Vaghefi N, Welgemoed T, Wingfield MJ. (2022) IMA genome‑F17. 13:19. 10.1186/s43008-022-00104-3
Wienk R, Mostert‑O’Neill M, Abeysekara N, Manosalva P, Freeman B, van den Berg N. (2022) Genetic diversity, population structure and clonal verification in South African avocado cultivars using single nucleotide polymorphism (SNP) markers. Tree Genetics and Genomes 18(41) 10.1007/s11295-022-01573-8 PDF
Joubert M, van den Berg N, Theron J, Swart V. (2022) Transcriptomics Advancement in the Complex Response of Plants to Viroid Infection. International Journal of Molecular Sciences 23(7677) 10.3390/ijms23147677 PDF
Backer R, Engelbrecht J, van den Berg N. (2022) Differing Responses to Phytophthora cinnamomi Infection in Susceptible and Partially Resistant Persea americana (Mill.) Rootstocks: A Case for the Role of Receptor-Like Kinases and Apoplastic Proteases. Frontiers in Plant Science 13 10.3389/fpls.2022.928176 PDF
Hartley J, Engelbrecht J, Van den Berg N. (2022) Detection and prevalence of Rosellinia necatrix in South African avocado orchards. European Journal of Plant Pathology 10.1007/s10658-022-02532-8