1916-17 DEPAKTMENT OF LANDS, FORESTS AND MINES. 157 



The plants mentioned are secondary hosts of the White Pine Blister Rust and 

 are, undoubtedly, one of the channels by which the disease is distributed. In order 

 to prevent the development of further areas of infection in the main white pine 

 districts it is considered necessary to prevent the distribution of such stock through 

 such districts. 



5. That restrictions be placed on the movement of Ribes and Grossularia from 

 nurBeries in the I'rovinces of Ontario and Quebec to other provinces. 



The distribution of such stock from nurseries in affected districts in the Pro- 

 vinces of Ontario and (Quebec might spread the disease rapidly and nullify efforts 

 for its control made by other means. This is specially necessary to protect the 

 white pines of the Pacific coast. While the eastern white pine area is by far the 

 most important on the continent a numl)er of five-needle white pines, which are 

 known to be susceptible to the disease, are present on the Pacific coast, covering 

 areas of such magnitude that their freedom from the disease would be a matter of 

 extreme importance. There is no record as yet of the presence of the disease in 

 British Columbia or the western states, and it is considered by foresters and path- 

 ologists as extremely desirable that the disease should be kept from these areas. 

 The measures necessary to attain this end would involve a quarantine to prevent 

 the shipment of nursery pines and currants from the eastern infected districts into 

 areas not yet reached by the rust. 



6. The only hope of growing white pine in the future depends on our ability 

 to keep it free from this disease. It is Avell recognized that in order to do this all 

 plants of the genera Ribes and Grossularia (curraiits and gooseberries) must be 

 removed from and around the ])inc area. It is impossible with our present know- 

 ledge to state the exact distance at which pines may be safely grown and a great deal 

 of observation and experiment will be necessary in order to ascertain this distance. 

 Control areas for this purpose have already been established in several of the New 

 England states, and it is highly advisable that similar control areas should be 

 established under Canadian conditions. If these control areas are begun im- 

 mediately we shall have obtained in a few years definite information on the most 

 critical arid vital point in regard to this disease. Unless definite information of 

 this kind can be secured shortly the encouragement of pine growing or the e-^tablish- 

 ment of new pine areas will be a very uncertain project. There is still needed a 

 great deal of investigation which can only be carried out by the plant pathologist. 

 Some work has already been done in Canada along this line, but there are so many 

 questions in regard to the disease which need immediate investigation that it is 

 felt that special attention should be given to such investigation for a number of 

 years to come. 



7. The problem in its extent no longer concerns one department or government 

 alone. It is no longer entirely a plant pathological question, but necessitates co- 

 operative action between departments and governments, and with foresters, lumber- 

 men, nurserymen, fruit growers, and other interests. Unless all combine in the 

 support of necessary measures it will be impossible to carry out the work success- 

 fully as it cannot be done by government action alone. 



8. That in order to ensure full co-operation and concentration of effort it is 

 considered advisable that a commivssion, having executive authority to direct the 

 necessary work to control the White Pine Blister Rust in Canada, should be formed 

 and duly empowered by the governments and associations concerned, such coni- 

 mission to consist of representatives of the following bodies : 



