VIEW ARTICLE

Cytology and Histology

Histopathology of Root Disease Incited by Thielaviopsis basicola in Ilex crenata. Robert L. Wick, Research associate, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061; Laurence D. Moore, associate professor, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061. Phytopathology 73:561-564. Accepted for publication 17 November 1982. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-561.

Black root disease caused by Thielaviopsis basicola in Japanese holly cultivar Helleri was examined histologically. All primary root tissues were colonized, but the hypodermis, endodermis, and vascular system were partially resistant. Lesions expanded by the intracellular growth of thin-walled, hyaline hyphae that were constricted behind the hyphal tip. Subsequent hyphae were thick-walled and contained many cross-walls and constrictions. T. basicola was compartmentalized in the cortex 9- 14 days after inoculation.