Hendersonula Dieback of Mango in Niger. P. Reckhaus, Deutsche Gesellschaft für Technische Zusammenarbeit. I. Adamou, Direction de la Protection des Végétaux, B.P. 10.115, Niamey, République du Niger. Plant Dis. 71:1045. Accepted for publication 15 July 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-1045D.
Since the early 1980s, a die back disease has caused severe damage on mango trees (Mangifera indica L.) in the Republic of Niger. The fungus most commonly isolated has been Hendersonula toruloidea Natt. (identified by Commonwealth Mycological Institute), a facultative, wound-invading pathogen with a broad host range. Symptoms, which develop only during periods of high relative humidity and high day and night temperatures, include sudden wilting of young shoots, twigs, or whole branches. Leaves turn bright red-brown but do not fall off. Cankers develop on infected branches and exude clear drops of gum. Internal tissue is dark brown to black. During the rainy season, black carbonaceous pycnidia occur containing hyaline to light green, ellipsoid pycnidiospores that are mostly one-celled and measure 11.1 X 4.4 µm. Wound inoculations of 2- to 3-mo-old mango seedlings and of twigs (1-1.5 cm diam.) of adult mango trees, using small disks of mycelium and arthrospores containing agar as inoculum, proved the pathogenicity of H. toruloidea; typical symptoms started to develop as early as 4 days after inoculation. We believe stress factors, mainly water stress, enhance severity of the disease.