Research: Citrus Black Spot

Downloads:   RCBS call   CBS research strategy    Preharvest proposal    Postharvest proposal   

Programme Coordinator:

Dr. Tian Schutte (CRI)

Collaborating researchers involved:
Dr. Paul Fourie (CRI), Elma Carstens (CRI at SU)

Citrus black spot is problematic in the citrus production regions with summer rainfall. Apart from fruit being down-graded from a blemish viewpoint, the disease is also considered to be of quarantine importance by certain of our existing or new/future export markets. Research in this project focuses on the aspects summarised below:

Market Access

  1. Circumscription and maintenance of selected production areas as "pest free" or "of low pest prevalence"
  2. Adherence to permitted MRL levels
  3. Packaging of local and international research findings to facilitate market access negotiations

Etiology + Diagnosis

  1. Develop detection techniques to facilitate rapid detection and diagnosis
  2. Characterise variability in pathogen populations


  1. Study epidemiological aspects that would facilitate improvement of management strategies
  2. Elucidate the role of Guignardia mangiferae in the CBS complex

Disease management

  1. Formulate and evaluate CBS management strategies for high and low disease prevalence areas
  2. Structuring of spray programmes to improve control, adhere to MRL and limit fungicide resistance
  3. Optimisation of spray application in orchards
  4. Evaluation of novel and GRAS chemical compounds and biocontrol agents for control of CBS
  5. Host resistance
  6. Product comparison / evaluation

Inoculum Management

  1. Formulation and evaluation of sanitation strategies that would reduce primary inoculum and/or break the life cycle of CBS
  2. Formulation and implementation of pathogen elimination strategies from propagation material