Mango malformation in South Africa: occurrence of conidia of Fusarium mangiferae on malformed panicles and leaves
Mango malformation caused by Fusarium mangiferae is a serious disease in South Africa, causing severe economic losses annually. The aim of this study was to determine the occurrence of conidia of F. mangiferae on malformed panicles and leaves in a 'Sensation' mango orchard at the Agricultural Research CouncilRSQUOs Institute for Tropical and Subtropical Crops (ARC-ITSC) in Nelspruit, Mpumalanga, South Africa, in order to optimise disease control. Malformed panicles and leaves were collected weekly during 2013 and 2014, spores washed off from panicles and leaves respectively and plated onto a semi-selective medium for Fusarium to determine spore concentrations. The average number of conidia per gram panicles and gram leaves were calculated for each sampling date. Results showed that low levels of conidia were detected on malformed panicles in the first three months of flowering (July to September). Spore numbers increased slowly through the following month (October), jumped dramatically the next month (November) and decreased thereafter. An increase in conidial number coincided with drying out of individual flowers on the malformed panicles. The presence of spores on the leaves coincided with the detection of high numbers of spores on malformed panicles. This is also the time when infection of terminal buds takes place. Spraying of fungicides should be focused on when inoculum is available to keep inoculum levels as low as possible and to protect the terminal buds from infection.
Schoeman, M.H., Zulu, N.B. and Botha, F.A. (2017). Mango malformation in South Africa: occurrence of conidia of Fusarium mangiferae on malformed panicles and leaves. Acta Hortic. 1183, 239-244
Mangifera indica L., 'Sensation', disease, spores, spray programme, fungicide