Disease Note

First Report of Terminal Crook Disease, Caused by Colletotrichum acutatum, on Pinus radiata Seedlings in South Africa. J. E. Lundquist, Plant Protection Research Institute, Private Bag X5017, Stellenbosch 7600, South Africa. Plant Disease 68:732, 1984. Accepted for publication 16 April 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-732b.

In January 1983, symptoms of terminal crook disease, including severe stunting, abnormally thick stems, dead and brown terminal needle clusters, and crooked or multiple stems, were observed on seedlings of Pinus radiata D. Don at Kruisfontein State Forest in the southern Cape, South Africa.  Nearby seedlings of P. pinaster Ait. and P. elliottii Engelm. were unaffected.  An isolate of Colletotrichum acutatum Simmonds, which produced a carmine pigment in culture, was isolated from infected seedlings.  Pathogenicity tests confirmed the isolate to be the causal agent.  In September 1983, a survey of all pine nurseries in the southern and eastern Cape showed the disease to be confined to Kruisfontein State Forest.  This is the first report of the disease in South Africa.

Reference: Baxter, A. P., et al. S. Afr. J. Bot. 2:259, 1983.