272 MANUAL OF TREE DISEASES 



TwiG-BuGHT 



Caused by Cenangium ferruginosum Fries 



This disease is reported as common and destructive in Europe 

 on Scotch, Austrian and white pines and on European silver 

 fir. In this country very little mention of it has been made. 

 It is reported on white pine in Ohio and the causal fungus has 

 been found on long-leaf, western yellow and Monterey pine. 

 On these latter trees the fungus was not shown to be parasitic. 

 Mature trees are more often affected than younger ones and 

 the disease is unknown on trees less than five years old. In 

 Europe this disease is said to occur in epiphytotics which sweep 

 over large forest areas. 



Symptoms. 



The terminal buds of affected twigs die in the spring. Later 

 the older needles turn red and die from the base to the tip. 

 The dead needles fall and leave the twigs bare. 



Small fruiting-bodies are formed on the dead twigs and 

 branches. In wet weather the fruiting-bodies open and are cup- 

 shaped, measuring about one-eighth of an inch across. During 

 dry weather they close and are more or less globose. In this 

 condition they are dusty brown or black but when they are open 

 the inner surface of the cup is yellowish or dirty greenish yellow. 



Cause. 



This twig-blight of pine is supposed to be caused by the 

 fungus Cenangium ferruginosum. Asci containing ascospores 

 are borne on the yellowish inner surface of the fruiting-bodies. 

 The ascospores are forcibly ejected and borne by the wind for 

 long distances. Other types of fruiting-bodies, resembling 

 those described above, are also formed which produce simple 

 spores. These, however, are not known to play any important 

 part in the life history of the fungus. There is some question" 

 whether this fungus is primarily responsible for this disease. 



