358 MAINE AGRICULTURAL EXPERIMENT STATION. I9IO. 



fungus is of interest not so much on account of its economic im- 

 portance, but because it represents a genus new to America. 



Rhizopiis decay. A soft rot of over-ripe apples is sometimes 

 caused by black mold. This rot may be recognized by the fact 

 that the mycelium which grows out over the surface of the af- 

 fected apple is composed of thicker threads than are found in 

 other apple decay fungi. If apples attacked by the black molds 

 are kept in a warm, moist place the mycelium forms a thick 

 growth on the surface. The spores are borne in little capsules 

 on the ends of long stalks. When the spores are mature the 

 whole mass becomes black in color. 



The black molds are regarded as saprophytes as they are able 

 to attack only ripe apples. They may cause considerable loss, 

 however. To prevent this loss it is necessary to use the same 

 precautions that are taken in the case of blue mold. 



Other apple rots. In the course of the study of apple dis- 

 eases, fruit has been inoculated with a number of other fungi 

 isolated from wood, leaves, or fruit of the apple in order to deter- 

 mine whether these fungi are capable of causing decay. 

 Coryneiim foliicolum Fckl., and a species of Cytospora from 

 diseased wood, produced a small amount of decay ; Coniolhyrhim 

 pirina (Sacc.) Sheldon, Phyllosticta limit ata Pk.. Cladosporium 

 herbamm (Pers.) Link, and 3 undetermined species of 

 Aspergillus, showed a little growth at the points of inoculation 

 but did not spread to cause decay. One fungus which has been 

 determined as Dcmatium pulliilans DeBary has been found con- 

 stantly associated with diseased apple tissues not only of the fruit 

 but also of the leaves and wood. On account of the constant 

 association of this fungus with apple rots, it was tested by means 

 of inoculations but it did not cause decay. It may be possible, 

 however, that when associated with other fungi the decay is 

 hastened by its presence. 



DISEASES OF THE WOOD. 



Canker and Twig-blight. The term canker has become such 

 a general one as not to admit of easy definition. It is commonly 

 used to describe the condition of branches of trees in which an 

 area of bark has been killed and has broken away so that a por- 

 tion of the wood is laid bare or is covered only by cracked and 

 roughened bark which does not protect the wood. In the 



