Disease Note.

New Report on Rust on Kikuyu Grass in South Africa Caused by Phakopsora apoda. . R. Adendorff, Department of Microbiology and Plant Pathology, University of Natal, Private Bag XOI, Scottsville, 3209.. F. H. J. Rijkenberg, Department of Microbiology and Plant Pathology, University of Natal, Private Bag XOI, Scottsville, 3209. Plant Dis. 79:1187. Accepted for publication ll September 1995. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-1187B.

In 1986 an outbreak of rust on kikuyu grass (Pennisetum clandestinum Hochst. ex Chiov.) pastures was observed in Richmond, Natal, South Africa (2). The rust fungus, Phakopsora apoda (Har. & Pat.) Mains, has subsequently been found in other areas in the Natal midlands. Observations of symptoms, disease development, and fungal morphology correlate closely with those made by Gardner (1). Disease development is enhanced by cool, moist, shady conditions. A high incidence of rust develops in fall, but the disease is scarce over winter after host die-back from frosting and reduced rainfall. The uredinia are more abundant toward the distal portions of older leaves, causing chlorosis and eventually necrosis of these areas. Kikuyu grass is one of the most important pasture and lawn grasses in South Africa. Although the rust does not appear lo kill plants, infected leaves have a substantially reduced photosynthetic area. The identification of this fungus was confirmed by J. F. Hennen at the Arthur Herbarium, Purdue University, West Lafayette, Indiana.