364 



FUNGOUS DISEASES OF PLANTS 



or distorted. This disease is not likely to be serious where proper 

 ventilation and subirrigation are provided for. 



Septoria Chrysanthemi Cav. may become a serious pest upon 

 the maturing leaves of the cultivated chrysanthemum. 



LII. CURRANT CANE BLIGHT 



Dothiorella 



This disease appears to be most abundant in the Hudson 

 Valley in New York. It has, however, been found in other 

 sections, though not destructive. The affected canes are wilted 

 and killed during midsummer. The disease is probably more 



easily seen during a dry period on ac- 

 count of the fact that when the water 

 supply is abundant, it may not be 

 noticeable during the growing season. 

 The fungus producing this disease has 

 been isolated from both the diseased 

 wood and pith, and upon infection is 

 capable of reproducing the disease. Sev- 

 eral fruiting stages have been found, at 

 least one of which is unquestionably a 

 stage in the life cycle of this fungus. It 

 has been difficult to identify all of the 

 spore forms with certainty, but the pyc- 

 nidial stage would be considered a species 

 of Dothiorella (Fig. 182). Successful 

 infection experiments with mycelium 

 obtained from germinating pycnospores 

 have been made. The relationship of 

 this fungus to an ascogenous stage 

 sometimes associated with it, or follow- 

 ing it, upon the dead canes has been 

 under careful study, but has not yet 

 been reported. The fungus grows read- 

 ily upon any of the solid nutrient media, 

 - .ellaon Producing a considerable gray-green 

 Currant Canes mycelium. 



