Disease Note

Colletotrichum gloeosporioides/ Shoot Blight of Greenhouse-Grown Western Hemlock Seedlings in British Columbia. W. Lock, Canadian Forestry Service, Victoria, B.C. . J. R. Sutherland, J. J. Dennis, and J. C. Hopkins, Canadian Forestry Service, Victoria, B.C. Plant Dis. 68:628. Accepted for publication 19 March 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-628b.

Shoot blight caused by Colletotrichum gloeosporioides Penz., first observed on 22 June 1983, affected about 25,000 4-mo-old western hemlock (Tsuga heterophylla (Raf.) Sarg.) in a greenhouse near Vancouver. Symptoms progressed upward from the lower shoot and included crooking of lateral and terminal shoot tips and clearly defined stem and tan-brown needle lesions; acervuli formed on dead tissues. Losses were most severe in the center of benches. The fungus sporulated and produced typical cultures on malt extract agar; it was identified at the Commonwealth Mycological Institute. Pathogenicity was confirmed in a growth chamber. Benomyl-chlorothalonil sprays at label rates controlled the disease. This is the first report of C.gloeosporioides<> affecting a conifer.