24 U.S. DEPT. OF AGRICULTURE MISC. PUB. 939 



Alberta, ground and aerial surveys of dwarfmistletoes on lodgepole 

 pine were initiated in 1960 to improve the methods of survey and 

 assessment of damage. 



Compilations of the pathogens of Pinus, Quercus, and Populus have 

 been completed. Six regional reports distributed earlier this year 

 summarize the findings for the extensive regions of Canada covered 

 by each, presentation. These data will be collated and revised in one 

 publication. In addition, a comprehensive report on the diseases of 

 Pinus with detailed annotations on each pathogen is in an advanced 

 stage of preparation. This will be the first in a planned series of de- 

 tailed annotated compilations of the diseases of native and exotic trees 

 and should prove of interest to workers in other countries. A series 

 of descriptive publications covering the diseases of major tree species 

 is envisaged and the first of these dealing with lodgepole pine is in 

 preparation. 



Test Plantations of Exotic Trees 



Numerous species of exotic hardwoods and conifers have been estab- 

 lished in plantations throughout Canada during recent years by indus- 

 tries and by provincial and federal governments. Unfortunately, no 

 central agency has the responsibility to collate and ensure the most 

 effective development of these plantings. Also, these plantations have 

 not been grown specifically to determine susceptibility to native dis- 

 eases. As a result, many plantations may not have been located in 

 the environment most favorable for tree growth and resistance to 

 native diseases. Nevertheless, many of these plantations are yielding 

 data on diseases that are recorded in the Annual Report of the Forest 

 Insect and Disease Survey (3) . 



In British Columbia a central registry for all introduced trees and 

 test plantations in the Province has been set up by the Forest En- 

 tomology and Pathology Laboratory, Victoria, and by the B.C. Forest 

 Service (7). This development recognizes the dangers involved in 

 the introduction of exotic trees and the objectives are to register all 

 plantations, appraise disease conditions periodically, assess species 

 suitability, and to prevent the introduction of damaging foreign 

 diseases. The exotic plantations under observation now total 168 and 

 are generally of recent origin. The 1960 Survey report (3 ) provides 

 a progress statement on the condition of these plantations. New 

 host-fungus records are tabulated and unfavorable site conditions are 

 suggested to have precipitated a 75-percent incidence of basal canker 

 by Armillaria meJlea in a plantation of "Robusta" and "Grandis" 

 poplar hybrids (6). 



In British Columbia, Ontario, and Quebec various studies on the 

 biology and host-parasite relationships of pathogens of hybrid pop- 

 lars (particularly in the section Leuce) include fungous species in 

 the genera Cytospora, Didymosphaeria, Dothichiza, Gloeosporium, 

 Melampsora. Pollaccia. Septoria, Hypoxylon. and others. In Ontario 

 and Quebec, special surveys are being conducted in test plantations 

 particularly of hybrid poplars established by provincial govern- 

 ments and industries, and reliable inoculation methods are under con- 

 sideration in the assessment of host susceptibility. Standardization 

 of inoculation procedures and host material is needed so that results 

 will be meaningful to all countries. In Ontario and British Colum- 

 bia resistance testing of white pines to white pine blister rust has been 



