ASCOMYCETES 



225 



Following a moist early summer I have found the perithecia abun- 

 dant on old leaves in the shade during a very dry period in late 

 summer (Fig. 90). 



Control. Thorough dusting with flowers of sulfur every ten days 

 is often sufficient. Ammoniacal copper carbonate is also effective. 



FIG. 90. ROSE MILDEW, PERITHECIA PRESENT 



Sulfuric acid i to 1000 has recently been recommended. No ex- 

 periments have been reported respecting the use of the " self- 

 cooked " lime-sulfur for the rose mildew, but there is reason to 

 believe that it may be far more effective than sulfur in this case. 



