A STUDY OF THE WHITE HEART-ROT OF LOCUST, CAUSED BY 
TRA METES ROBINIOPHILA 
C. H. Kauffman and H. M. Kerber 
(Received for publication February 24, 1922) 
Introduction 
The actual distribution of the active mycehum during the process of 
decay in living trunks of various timber trees, and the process of such decay 
in the production of "heart-rots," is still poorly understood. If one ex- 
amines the literature on the subject, it soon becomes evident, however, that 
sufficient data are at hand to conclude that the relation of any specific 
heart-rotting fungus to a specific tree is either specific itself or belongs to 
one of a group of type reactions. We are far enough in the study to realize 
that generalizations on these reactions are impossible. 
In the study of a rot caused by Trametes robiniophila Murr., we paid 
little attention to the number of trees affected or to the question of the 
value of locust timber. The inroads of the locust borer, and, in the more 
southern distribution of the locust tree, the abundant heart-rot due to 
Fomes rimosus, both loom as so much more important enemies to be con- 
trolled before the locust tree can find its rightful place in lumber economy, 
that it seems futile to attempt to make an important case of the rot in 
question. 
Our attention was therefore directed to an analysis of one case: the 
macroscopic and microscopic characteristics of the rot ; its mode of advance ; 
the distribution of the mycelium in the various portions of the affected 
trunk; and its effect on the various elements of the wood. 
That the white heart-rot of Rohinia Pseiido- Acacia L. is quite frequent 
in southern Michigan there is no doubt. Its presence is not to be reckoned 
by the number of sporophores observed, since it appears to fruit sparsely, 
and when it does the sporophore rarely lasts more than one season or is 
soon attacked by insect enemies or disintegrated by wind and weather. 
The black-locust tree is found scattered along some of the Ann Arbor 
streets, and not a few show symptoms of heart-rot. From year to year 
sporophores may be noticed on some of them, and the tree selected for 
study had had a large yellowish sporophore on it the year before, and at 
the time of cutting had produced another from an old frost crack that had 
almost healed over; in addition, signs of several old scars left by former 
sporophores were still distinguishable on the trunk. Although the tree 
was suffering from both borer attacks and the heart-rot, as shown by a 
number of large dead branches and the straggly condition of the crown, 
493 
