Disease Note

Colletotrichum gloeosporioides on Clivia in South Africa. V. H. Whitlock, Department of Microbiology, University of the Witwatersrand, Johannesburg 2001, South Africa. Plant Dis. 70:800. Accepted for publication 26 March 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-800f.

Colletotrichum gloeosporioides (Penz.) Sacc. is a widespread pathogen in South Africa but has not been reported as a pathogen on bulbous ornamentals in that country. In February 1985, a number of Clivia miniata Regel from several home gardens in the Johannesburg area were affected with a destructive disease. Leaf symptoms were characteristic concentric necrotic rings, many with prominent yellow halos, that rapidly spread over the leaf. The bulbs remained symptomless. Infected plants invariably died. C. gloeosporioides was consistently isolated from lesions. Identification was based on culture and conidial morphology. The fungus was grown in the laboratory, and a conidial suspension (about 4.2 × 10⁵ conidia per milliliter) was sprayed onto the leaves of six C. miniata plants in the greenhouse. Symptoms identical to the field symptoms appeared after 14–19 days.