ETIOLOGY AND CONTROL OF SOME MANGO BLOSSOM DISEASES IN SOUTH AFRICA

Nattrassia mangiferae was consistently isolated from blighted mango inflorescences.
Isolates of N. mangiferae caused blossom blight when artificially inoculated on healthy panicles. Alternaria alternata and Colletotrichum gloeosporioides were found to cause small, dark, necrotic lesions on mango inflorescences.
Blossom blight seems to develop due to systemic infection by N. mangiferae. The incidence of blossom spot was positively correlated with rainfall. Oidium mangiferae infected once flowers had begun to open on the panicles(3 – 5 weeks after budbreak). Prior to this period and during fruit set, no significant O. mangiferae infection occurred.
Various fungicides, sprayed at fortnightly intervals during flowering, were screened for their efficacy in controlling blossom blight, blossom spot and powdery mildew.
Flusilazol or pyrazophos resulted in significant disease control and consistently increased fruit set and yield above the untreated control.

IV International Mango Symposium

J.H. Lonsdale, J.M. Kotzé

https://doi.org/10.17660/ActaHortic.1993.341.38