Soilborne Diseases

Programme Coordinator:

Dr. Jan van Niekerk

Collaborating Researchers:

M.C. Pretorius, Prof. Adele McLeod, Charl Kotze

Research Conducted: 

Research and services on all soilborne diseases and nematodes, and most specifically on Phytophthora root, collar and branch rot, citrus decline and the citrus nematode, Tylenchulus semipenetrans, and focuses on the aspects summarised below:

Market Access

  • Adherence to permitted MRL levels
  • Packaging of local and international research findings to facilitate market access negotiations

Etiology & Diagnosis

  • Elucidate the etiology of soilborne diseases in different citrus growing regions
  • Develop detection techniques to facilitate rapid detection and diagnosis
  • Characterise variability in pathogen populations


  • Study epidemiological aspects that would facilitate improvement of management strategies

Disease Management

  • Integration of chemical and biological strategies to improve soil and plant health
  • Implementation of strategies to limit advanced microbial degradation (AMD) or fungicide resistance buildup
  • Evaluation of novel and GRAS chemical compounds and biocontrol agents for control of soilborne diseases
  • Rootstock resistance against soilborne pests and diseases

Inoculum Management

  • Formulation and evaluation of sanitation strategies that would reduce primary inoculum
  • Implementation and optimisation of pathogen elimination strategies from propagation material


  • Standard operating procedures to maintain phytosecurity of Citrus Improvement Programme