Evaluation of fungicides for the control of Botryosphaeria protearum on Protea magnifica in the Western Cape Province of South Africa

A range of fungicides was tested in vitro for their effect on mycelial inhibition. Selected products showing potential for disease control were then further tested under field conditions. The most effective fungicides in the in vitro tests were tebuconazole, benomyl, prochloraz mc, iprodione and fenarimol. In field trials, a 25-85% reduction in the occurrence of stem cankers caused by Botryosphaeria protearum was achieved if fungicides were applied or sanitation pruning was implemented. The best control was obtained with treatments of prochloraz mc alternated with mancozeb. Applications of bitertanol and fenarimol also significantly reduced the occurrence of cankers.