30 CEANBERRY DISEASES. 



the exception of the short neck, which protrncles above the surface 

 of the mycelial subiculum (PL III, fig. 13) . The fungus grows best at 

 ordinary laboratory temperatures, varying from 20° to 26° C, and 

 the mature perithecia are produced in from fourteen to thirty -days. 

 As in the case of Guignardia, and for the same reasons, we have been 

 unable to determine yet at what time infection of fruit and vines 

 takes place. Ajjjjressoria have not been observed on diseased berries, 

 but, as already stated, they have been found on leaves, with the germ 

 tube penetrating the tissue. The fungus is found in a fruiting condi- 

 tion on the cranberry bogs soon after the water is removed from the 

 vines in the spring. It is therefore probable tha't infection of the 

 young leaves begins about this time. 



This fungus also evidently has the power of remaining in a dor- 

 mant or inactive condition in the leaves and fruits, as is show^n by the 

 development of the fungus in apparently normal and healthy leaves 

 and fruits wdiich have been disinfected and kept in moist chambers in 

 the laboratory. That the original infection is from external sources 

 is shown by the presence of appressoria on the leaves, the germ tubes 

 of which have been found entering the tissue (PI. Ill, fig, 22). 



TREATMENT. 



What has been said in regard to the treatment of cranberry scald 

 applies equally well to the rot. The two diseases almost always occur 

 together, and Bordeaux mixture applied in the same manner as for 

 scald has given satisfactory results. 



ANTHRACNOSE. 



Anthracnose is a disease not heretofore reported as affecting the 

 cranberry. As is the case in most other diseases to which this name 

 is applied, it is due to one of the fungi which have been called Gloeo- 

 sporium. The ascogenous stage of the fungus having been produced, 

 it is found to belong to the genus Glomerella and has been named 

 Glomerella riifomacnlans vaccinii Shear."^ Like the scald and rot, 

 this disease is at all times difficult, and usually impossible, to diag- 

 nose by a macroscopic examination of the diseased berries. The 

 berries from which Ave have isolated the fungus which causes this 

 disease have not been uniform in appearance. In one case the berry 

 was very soft and light colored, while in other cases the fungus did 

 not seem to have developed so rapidly and the portion of the fruit 

 a^ffected by the disease w^as not so soft. Acervuli sometimes develop 

 on the diseased berry, but usually they do not. Judging from the 

 infrequency of occurrence of this fungus in cultures made from 

 affected berries, the disease is much less injurious than the rot or 



110 



