Wetwood of Elms 



J. CEDRIC CARTER 



THE investigation of wetwood 

 reported in this paper is the out- 

 growth of studies of an unusual 

 wilt observed on a large number of 

 American elms in the Village of Hinsdale, 



Assistant Professor of Bacteriology at the 

 University of Illinois, made many helpful 

 suggestions in connection with the identi- 

 fication of the bacterium associated with 

 wetwood. Preliminary analyses of sap 



Illinois, in July and August, 1939. As from wetwood-affected elms were run by 

 studies of the wilt progressed, it became Dr. F. F. Weinard, Associate Professor 

 apparent that this wilt was a secondary of Floricultural Physiology at the Univer- 



manifestation of disease intimately related 

 to slime flux, a chronic bleeding at crotches 

 and wounds, to abnormally high sap 

 pressure in the trunk, and to wetwood, a 

 water-soaked, darkly discolored condition 

 of the heartwood. The investigation has 

 shown that all of these conditions — wilt- 



sity of Illinois. Mr. O. T. Lay, in charge 

 of the city office of the United States 

 Department of Commerce Weather Bu- 

 reau at Chicago, furnished the monthly 

 meteorological summaries for Chicago. 

 Photographic illustrations for the frontis- 

 piece and for figs. 19, 20, 21 and 22 were 



ing, high sap pressure and water-soaked, prepared by Mr. Ray R. Hamm, Manager 



discolored wood — are phases of the wet- 

 wood disease, and that a bacterium, 

 described as a new species, can cause 

 wetwood in elms. 



Acknowledgments 



The author wishes to express his sincere 

 appreciation to all those who have assisted 

 in any way during the course of this in- 

 I'estigation. Special recognition is given 

 to the Village of Hinsdale foresters — 

 Mr. W. E. Rose through 1941 and Mr. 

 J. F. Shafer since 1942 — for their assist- 

 ance with the portion of the investigation 

 that was carried out at Hinsdale. Elms 

 affected with wetwood on Hinsdale park- 

 ways were used in parts of this investiga- 

 tion. Permission to use these trees was 

 arranged with the government of the 

 V^illage of Hinsdale through Mr. Robert 

 S. Hopkins, Commissioner of Public 

 Works, and much of the labor, equipment 

 and material used in treating and examin- 

 ing them was furnished by the Village. 

 Dr. O. W. Rees and Dr. G. C. Finger, 

 chemists of the Illinois State Geological 

 Survey, gave many suggestions in regard 

 to methods of analyzing sap and gas taken 

 from affected elms. Some gas samples 

 were analyzed by Mr. C. D. Lewis, 

 Assistant Chemist of the Illinois State 

 Geological Survey. Dr. F. M, Clark, 



of the University of Illinois photographic 

 and blueprinting laboratory. Mrs. Lucile 

 Rogers Carter assisted in many ways in 

 the preparation of this manuscript. The 

 author is indebted to Dr. L. R. Tehon, 

 head of the Section of Applied Botany and 

 Plant Pathology of the Illinois Natural 

 History Survey, for suggestions made 

 during the course of this investigation. 



Review of Literature 



A bacterial vascular disease of Lom- 

 bardy poplar, Populus nigra italica 

 Muenchh., was described by Hartley & 

 Crandall (1935). Crandall, Hartley & 

 Davidson (1937) called this disease wet- 

 wood and described it as "a water-soaked 

 condition of the central wood." They 

 reported wetwood in species of Abies, 

 Morus. Platanus, Populus, Prosopis, Pru- 

 nus, Quercus, Salix, Tsuga and JJlmus, 

 and also Elaeagnus cuttings. 



Crandall, Hartley & Davidson (1937) 

 mentioned that slime flux, in several 

 species, appeared to be a pathological phe- 

 nomenon of wetwood. Dodge (1937), in 

 a discussion of slime flux, stated, "A tree 

 should not be diagnosed as suffering from 

 slime flux unless there is a 'wet wood' 

 condition of the heartwood and unless the 

 bleeding of moisture from the tree issues 

 from this heartwood." He pointed out 



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