78 BOARD OF AGRICULTURE. [P. D. 4. 



observe the progress of the disease. In a letter dated November 

 27, 1916, he writes: — 



While we have not had the disease long enough in this country to 

 show what it may do in mature white pines, we do have in a few cases 

 very plain indications of what this disease will undoubtedly do either 

 in mature or immature trees. We have instances of young stands of 

 wliite pine up to twenty or twenty-five years of age where about 40 

 per cent of the total stand on quarter-acre plots is killed or has the main 

 stem girdled by the disease, which of course means the death of the 

 affected trees within a very few years. In these same cases 85 per cent 

 of the total stand was affected. In the case of one large tree wliich I 

 have had a chance to watch for several years, where a severe outbreak 

 of the disease was present within 200 feet, I have seen numerous branches 

 3 and 4 inches in diameter taken off in the effort to remove the diseased 

 parts of the tree. A disease which will do this sort of thing of course 

 may ultimately take every branch off from the tree, no matter how 

 large it may be or how healthy in other respects. There is no doubt 

 that where this disease is allowed to go unchecked it will very seriously 

 threaten the life of any white pines that may be in the vicinity, no matter 

 how large or how small. Furthermore, it certainly will, by killing the 

 branches, utterly destroy the beauty of valued ornamental trees by 

 making them unsightly and by destroying the regularity of their branches, 

 which is the great charm of this species. A large tree which once becomes 

 infected in its branches cannot be thoroughly inspected for the disease, 

 and for this reason efforts to cut out the diseased branches in a large 

 tree are not only futile but are foolish. The result in such cases is that 

 scattering infections remain in the top of the tree where spores are pro- 

 duced, which because of their height from the ground obtain a maxi- 

 mum distribution in the wind. Such trees are the most dangerous centers 

 for the disease that we have to contend with. The oldest outbreaks 

 of the disease of which we know in tliis country date back only some 

 twelve years so far as we can judge from what is left within those in- 

 fected areas. If within this time we may get dozens of 3 and 4 inch 

 branches taken out of a tree 50 to 60 feet in height, what may be ex- 

 pected after the disease has been in the locality twenty years ? 



Dr. J. F. Martin has had immediate supervision of the field 

 work on the rust in Massachusetts during the year, and from 

 his observations in the field presents the following statement: — 



While the disease has not been present in Massachusetts long enough 

 to kill mature trees, it has given plenty of evidence of what it can do 

 and what its ultimate effect upon such trees will be. At Lenox and 

 Ipswich several trees ranging from 1 to 2 feet in diameter at the base 



