. Bulletin of the Department of Agriculture. Agriculture; Agriculture. UNITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 722 Contribntion f^om the Bureau of Plant Indnatry WM. A. TAYLOR, Chief Washington, D. C. PROFESSIONAL PAPER October 22, 1918 , A STUDY OF HEART-ROT IN WESTERN HEMLOCK By JAMES R. WEIR, Forest Pathologist, and ERNEST E. HUBERT ScientilSc Assistant, Office of Investigations in Forest Pathology CONTENTS Introdaction .....^ 1 Present Status of Western Hemlock in the Trades 2 Echinodontium tinctorium 3 The Fungus and Its Hosts .... 3 Geographic Distribution ..... 5 The D
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. UNITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 722 Contribntion f^om the Bureau of Plant Indnatry WM. A. TAYLOR, Chief Washington, D. C. PROFESSIONAL PAPER October 22, 1918 , A STUDY OF HEART-ROT IN WESTERN HEMLOCK By JAMES R. WEIR, Forest Pathologist, and ERNEST E. HUBERT ScientilSc Assistant, Office of Investigations in Forest Pathology CONTENTS Introdaction .....^ 1 Present Status of Western Hemlock in the Trades 2 Echinodontium tinctorium 3 The Fungus and Its Hosts .... 3 Geographic Distribution ..... 5 The Disease Caused by Echinodontium tinctorium 6 Outward Signs of the Disease ... 6 General Characteristics of the Rot . 9 Areas Studied and Field Methods Used 11 Page Methods Used in Presenting Data ... 14 Infection Age ...-. 16 Relation of Decay to Sigte and to Age . IS Relation of Decay to Vigor, Croivn Rat- ing, Size, and Volume ....... 22 Relation of Decay to Injury and to Sporo- phores 24 Theory of Infection .,. 30 Discussion of Results ....... 31 Methods of Control . 34 Summary ............ 36. WASHINGTON GOVERNMENT PRINTING OFFICE 1918. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States. Dept. of Agriculture. [Washington, D. C. ?] : The Dept. : Supt. of Docs. , G. P. O.
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