70 



TENTH BIENNIAL REPORT 



portion of the life of this disease of course is spent upon the pine, 

 producing large cankers, which eventually kill young growth and 

 maim and disfigure old trees by shutting off the supply of sap. In 



IP 9li5tepif)g drop5 

 on pioe barK 



FuDcjua threads 

 growin<^ 117 

 pine t'SriC /o' 



orange-Yellow 

 blisters or? 

 p\ne borK 



fungus 

 Tbreads 

 wbicb sprout 

 troiT? the spores 

 lo tbe cclomoo 



In 

 oranqc -Yellow 

 pustules on tbe 

 L/pder .sidt of 

 currant aod qooi>t;berrY 

 leaves 



Figure 1. 

 of the Bureau of Plant 



In 

 bair-liKe colorwos 

 on The under side of 

 current and t^oo&eberrv -leaves 



Life cycle of the White Pine Blister Rust. (Loaned by the courtesy 

 ndustry, U. S. Department of Agriculture.) 



(f- 



time there appear along the swelling of these cankers numerous white 

 blisters' which eventually break, disseminating orange-colored spores 

 of a powdery nature. (See Fig. 2). These may be noticed from 

 April to the middle of June. The spores are blown far and wide by 



