ROOT DISEASES AND INJURIES 



79 



ondary part. The fungus is so prevalent as a saprophyte that 

 its occurrence as a wound parasite and root-rotting fungus on 

 trees is not surprising. 



Symptoms. 



The bark and wood of the roots are affected and the living 

 tissues destroved. The deca^■ ma\- also extend up into the 



bark and sapwood of the lower 

 part cf the trunk (Fig. 6). 

 Trees with the root system 

 partially destroyed display 

 general symptoms of decline 

 and poor health, such as dead 

 limbs, scanty and light green 

 foliage, and but little annual 

 growth. In conifers a large 

 amount of resin exudes from 

 the base of the tree and ac- 

 cumulates as a hard cake (Fig. 

 6). The time from the first 

 signs of decline to final death 

 may extend over a period of 

 three or four or more years. 

 There are many diagnostic 

 symptoms by which this root- 

 rot may be identified. The 

 mycelium of the causal fungus 

 when growing in the soil out- 

 side the roots is bound to- 

 gether in long round, black 

 strands somewhat resembling 

 shoe-strings. These black strands may be found growing 

 attached to the bark of the roots and trunk or running 

 through the soil for long distances away from the affected 



Fig. 6.- 



■ White pine killed by shoe- 

 string root-rot. 



