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Disease Note

Occurrence of Procerum Root Disease Caused by Leptographium procerum on White Pine in Connecticut. V. L. Smith, Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven 06504. Plant Dis. 75:431. Accepted for publication 17 October 1990. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0431D.

White pine (Pinus strobus L.) in a commercial Christmas tree plantation in central Connecticut showed reduced shoot elongation, wilting and red-brown discoloration of the needles, resin soaking of the trunk, and dark brown cambial discoloration. Symptomatic trees were associated with poorly drained soil and were not infested with weevils or bark beetles. Leptographium procerum (Kendrick) M.J. Wingfield was consistently isolated from discolored wood tissue. Koch's postulates were completed on 1-yr-old white pine seedlings in the greenhouse. Seedlings were inoculated by placing actively growing mycelium in a stem cut, then were incubated for approximately 4 wk. Selective medium (2) was used to reisolate L. procerum from symptomatic seedlings. Although L. procerum has been shown to be transmitted by weevils and bark beetles (1), disease in this instance appeared to be related to poor site drainage rather than insect infestation. This is believed to be the first report of Procerum root disease on white pine in Connecticut.

References: (1) K. J. Lewis and S. A. Alexander. Can. J. For. Res. 16:1330, 1986. (2) K. A. McCall and W. Merrill. Plant Dis. 64:277, 1980.