Inoculum availability and infection patterns of Fusarium mangiferae, the causal agent of mango malformation in South Africa

Abstract

Mango malformation, caused by Fusarium mangiferae, is a serious disease of mango in South Africa, causing severe economic losses annually. The occurrence of conidia of F. mangiferae on malformed inflorescences and leaves and the timing of airborne infections were studied during 2013–2015 in a ‘Sensation’ orchard at Nelspruit and a ‘Kent’ orchard at Hoedspuit. At Nelspruit, a peak in conidia numbers on malformed inflorescences was detected in November in all three seasons. At Hoedspruit, a peak in conidia numbers on malformed inflorescences was detected in October 2014 and August 2015. The presence of conidia on the leaves coincided with the detection of high numbers of spores on malformed panicles at both locations. Airborne infections of vegetative branches at Nelspruit and Hoedspruit corresponded with high numbers of conidia on malformed inflorescences. Knowledge of periods when inoculum is available and critical periods for infection provided essential information for timely and more effective application of management strategies to control mango malformation in South Africa.