Occurrence, pathogenicity and survival of Macrophoma mangiferae in leaves, branches and stems of mango (Mangifera indica L.).
Okigbo R. N.
Author Affiliation: Department of Biological Sciences, Michael Okpara Federal University of Agriculture, Umudike, PMB 7267, Umuahia, Nigeria.
Plant Protection Science 37 : 138-144
Abstract : The frequency of occurrence and persistence of M. mangiferae on 4-year-old mango plants (Mangifera indica) growing under various conditions were investigated over two periods of 6 months (1994-95) in five locations in southeastern Nigeria (Umuahia, Enugu, Nsukka, Ojoto and Okigwe). Among the five locations studied, the frequency of occurrence of the disease was highest in Umuahia, with 65% for leaves and 41% for stems. The chances of the fungus to survive adverse conditions in mango tissues were higher in the stems and branches than in the leaves; more fungal colonies were recovered from the stems and branches than from the leaves. The fungus survived adverse conditions, forming structures such as chlamydospores and thick-walled hyphae under continuous light. In the dark, the fungus remained in the vegetative form and, hence, did not produce any sexual reproductive structure. When subjected to continuous light, the fungus produced pycnidia. Leaving dried leaves and fragments of dried stems and branches on the farms is likely to raise the level of primary inoculum for mango diseases.