2Q2 STRUCTURE AND LIFE HISTORIES 
This fungus is known as Albugo Candida, or more recently 
as Cystopus candidus. 
4. Downy mildew of grapes and cucumbers. 
FIG. 214. Witches' brooms on the hackberry (Celtis ocridenlalis) , 
caused by a gall-mite (Phytoptus sp.), or possibly by the mite in conjunc- 
tion with a powdery mildew (Sphcerotheca phytoptophyla) , which is usually 
found on the "brooms." 
5. Potato rot and "late blight," Phytophthora infestans 
(Mont.) DeBary. This disease was the cause of the 
failure of the potato crop and the consequent famine in 
