214 



W. V. AGR. EXPERIMENT STATION [Bulletin 137 



dency to remain on the tree for some time. The burs on in- 

 fected branches usually remain on the tree during the winter 

 following its girdling. 



Diseased trees very frequently produce sprouts or "suck- 

 ers" in considerable numbers. These may appear on the 

 trunk or near the base of the tree. Such sprouts soon become 

 infected, however, and very few survive more than two or 

 three years. 



FIG. 5. Young tree showing postules on smooth bark, and sprouts. (See also 



Fig. 11, page 221.) 



A closer examination reveals the diseased band near the 

 base of the affected portion. It is especially conspicuous on 

 smooth bark, causing a reddish brown discoloration and pro- 

 ducing numerous little pustules which break through the bark 

 and set free vast numbers of spores. These spore masses are 

 orange colored but vary considerably in appearance accord- 

 ing to climatic conditions. During warm, moist weather they 

 are especially prominent and sometimes may be seen as long, 

 curly, yellow threads issuing from the pustule (figure 6). 



