246 



REPORT OF THE 



No. 3 



types of rots, of the extent of their ravages, and the age at which the tree species 

 become susceptible to them. Studies on the rate of progress of deterioration are 

 also planned, information of essential importance in the rectifying of working 

 plans on a sustained yield basis, and of value in determining when a given stand 

 should be harvested. 



Owing to the fact that the identity of the fungi responsible for many of the 

 heart and butt rots is unknown, intensive laboratory research has been carried 

 on in this subject by C. W. Fritz, M.Sc, through the co-operation of the Univer- 

 sity of Toronto; investigations on fifteen forms have been completed and an 

 account of them will shortly be published. 



Fig. 6. — Type II: Butt rot of balsam. 



As an extension of the work on butt and heart rots some time has been 

 given to the question of their relation to the dying of balsam following bud 

 worm attack. 



(d) Rusts of balsam. — As a part of the preparation of a monograph on the 

 diseases of balsam, attention has been given to needle diseases. The rusts are 

 among the more important causes of such; they are essentially leaf parasites, 

 though in some cases the stems and branches may be involved. This special 

 group has been investigated by Dr. H. P. Bell, of Dalhousie University, Halifax, 

 who was associated with me in the field, and to whom a working place was granted 

 in the field laboratory through the courtesy of the Forest Branch. Many in- 

 teresting facts have been brought to light and two new species of rusts on balsam 

 discovered. Dr. Bell's paper on one set of these rusts has been accepted for 

 publication in the Botanical Gazette. 



(e) Collections. (1) Fungus diseases. — Many additions have been made 

 to our reference collections in pathology, including contributions from corres- 

 pondents in various states and provinces. 



