CURRANT DISEASES 211 
of transition from active elongation-growth to that of the 
maturation-stages. Within a week or two after the spores 
of the fungus are deposited upon the currant, signs of dis- 
ease appear. The bark, wood and pith are invaded by the 
mycelium. Sometimes the leaves also are attacked. The 
mycelium may be observed in the pith as a fine, whitish, 
webby growth. 
Shortly after early infection occurs, the fungus forms a simple 
spore-stage on the withering tips. This is known to patholo- 
gists as the Macrophoma-form. Following the development 
of this stage, from midsummer to autumn, a stromatic form 
appears ; this is called the Dothiorella-stage. This form shows 
as small, globose, sclerotic bodies on the shoots which have 
been killed in the earlier part of the season. Toward the end 
of the summer the stromata of the second or Dothiorella-type, 
instead of forming pycnidia, develop perithecia. In this condi- 
tion the fungus passes the winter. The following May and 
June pycnospores are formed. They are discharged the latter 
part of June or in early July. At the same time ascospores 
develop within the perithecia already mentioned. Thus 
pycnidia and perithecia may be found on old dead canes to- 
gether. 
Control. 
At the present time there is no method of treatment for 
currant cane-blight which can be confidently recommended. 
It has been shown that summer pruning, that is, the syste- 
matic removal of all diseased canes at frequent intervals 
during the spring and summer, is of no value so far as the 
control of cane-blight is concerned. Winter pruning is also 
inefficient, owing to the difficulty of recognizing affected canes 
while the plants are devoid of foliage. The careless piling 
of pruned canes along fences should be avoided. Such brush 
should be burned before the end of May, in order to destro 
the fungus. 
