Trees and Timber 397 



Ribes telial stage of the rust may infect pines on which they 

 fall. The first external evidence of disease appears one to 

 several years later. The bark thickens and later pycnia 

 develop. In the spring, secia, numerous or few, mature on the 

 swollen bark and free their orange-colored spores. These 

 spores falling on Ribes produce the next stage of the rust, 

 though they cannot directly infect pine. The rust is peren- 

 nial in the pine, the cankers enlarging year after year. Trees 

 attacked when young, c. g., under 25 years of age, are liable 

 to be killed. Older trees may merely lose branches or the 

 central, top shoot. The damage to white pines is very 

 serious. In 1909 the value of standing white pine was esti- 

 mated at $600,000,000, the sugar pine at $120,000,000. A 

 loss of even 1 per cent of this, which is a low estimate, is 

 significant. 



In 1912 laws were enacted to prevent entry into the United 

 States of foreign stock likely to harbor and introduce dan- 

 gerous fungi and insect pests. Rigid Federal and state 

 inspection is now exercised to prevent further spread of this 

 disease. Imported Ribes and white pine must be kept well 

 separated. If the disease is present, all Ribes should be 

 removed from the vicinity. At the present time, $530,448 

 of Federal appropriations and $267,300 of state funds have 

 been used to combat this disease. 



Bluing''-^ (Ceratostomella jnlijera (Fr.) Wint.). — The 

 characteristic symptom, bluing of the sapwood, begins in 

 August and September after the trees have been attacked 

 by beetles. The blue color starts near the base of the tree 

 and gradually spreads upward until the entire sapwood be- 

 comes blue. The presence of the mycelium of the above- 

 named fungus, which gains entrance through openings made 

 by the beetle and is initiated by spores carried by the beetle 

 is responsible for the color phenomenon. Blue wood is as 

 strong as normal, green wood, is tougher, and when dry, it 

 will last as long; but when wet, it rots rapidly. 



Leaf-cast {Hyyoderma) . — The needles die from the tips 

 toward the bases, becoming first reddish, then gray. Black 



