DISEASES OF SHADE AXD FOREST TREES. 103 



diseases in various parts of the country, but without success. 

 Then- jnv no such treatments for diseases of this character 

 known ro -cience, and the authors of these secret methods 

 freely acknowledge that their treatments are not recognized 

 by seinitiric workers. The public is cautioned against 

 patronizing these people. 



WHITE PINE BLISTER RUST. 



The blister rust (Pcridennium strobi Klebahn* ) of the 

 white pine, a European disease which has been introduced 

 into this country and apparently stamped out, but which may 

 be introduced again at any time, causes a spindle shaped, or 

 -ometinies irregular warty swelling on the 



Symptoms. 



trunks oi seedlings and young trees and upon 



the young branches of older trees. (Fiii- : ^> ) Those 

 -well ings do not occur until one or more years after the in- 

 fection. which makes it impossible to detect the disease in 

 ir> earliest stages. As these swellings approach maturity 

 they form 011 the surface rounded or elongated bodies measur- 

 ing oiie-eigbth to one-half inch across. The bodies have deli- 

 cate, whitish membrane coverings beneath which may be seen 

 masses of orange-colored spores. This membrane ruptures, 

 allowing the spores to escape (April to June), but may per- 

 sist for some time after the spores have been carried aw T ay. 

 If the spores are carried* to gooseberries or cur- Alternating 

 rants th< y attack the foliage and young shoots ho * ts - 

 and cause the "velvet rust" which produces two kinds of 

 spores, one kind by which the fungus can spread on the 

 L:< " seberries and currants and another by which It is returned 

 to the white pines. The disease is of very little importance 

 on the gooseberries and currants, but is very destructive on 

 the white and other of the five-leaved pines. It attacks none 

 of those with two or three needles. 



*Pcri<lerm'unn *tn>1)i Klobahn of the white and other five-leaved pinos is the 

 same as Croiiui-tiuii' i ibicola Diet, of the currant and gooseberry. 



