STEM END ROT DISEASES OF TROPICAL FRUIT - MODE OF INFECTION IN MANGO, AND PROSPECTS FOR CONTROL
In mango, postharvest losses do not result from infection at flowering or fruit set-fruitlets infected at this time are aborted. Natural infections by Dothiorella spp. reappear in stem end tissue (10% affected) of fruit 11 weeks after full flowering and are more prevalent in the peduncle 60% affected) at that time.
All fungi which cause stem end rots of mango (Dothiorella dominicana, Petrak & Cif. D. Mangiferae Syd. & But., D. 'long', P.mangiferae, L. theobromae, Cytosphaeria mangiferae Died and Pestalotiopsis sp.) were found as endophytes associated with healthy stem tissue prior to inflorescence emergence. Some of these fungi progressively colonised the inflorescence tissue, and were present in the pedicel tissue of some fruit 8 weeks after flowing.
Our results suggest that stem end rot pathogens are endophytes occurring widely on mature branches of mango trees. Mycelia of the fungi colonise inflorescence tissue as it matures and in certain conditions, reach the stem end of fruit. Infections then remain latent until after harvest or, until the unharvested fruit senesce.
In the future, control of this disease may be achieved by slowing down the colonisation process so that the fungi do not reach the stem end of fruit before harvest. Factors which may affect colonisation include watering regimes, defoliation and pruning practices.