136 FUNGI AND FUXGICTDES 



lateral bodies, known as sporidia. These germinate, 

 and when falling on the proper host, j^roduce the aecid- 

 ium stage, thus completing the cycle of the year." 



Treatment. — The development of the disease upon 

 seed beets, where alone, according to some authorities, 

 the first stage is passed, may probably be preyented by 

 spraying with some of the copper fungicides — the Bor- 

 deaux mixture, for examjDle. The removal and burning 

 of affected leaves is also recommended. 



Literature. — A good account of this disease, with 

 figures of the spores, may be found in the United States 

 Department of Agriculture report for 1887 (pp. 350-353). 

 It has also been discussed by Dr. Hals ted, in the Bui- 

 letin of the Iowa Agricultural College for 1888 ; and by 

 Professor Pammel, in Bulletin Xo. 15 of the Iowa Ex- 

 periment Station (pp. 235-23G). 



The Beet Leaf=spot Disease 



Cercospora beticola 



This disease appears to be more widely prevalent in 

 America than the leaf-rust. It first appears on either 

 the upper or lower surfaces of the leaf, or on both, in 

 the shape of small pale brown, more or less circular 

 spots, with lighter colored margins. At first these 

 spots may be no larger than a pin-head, but they grad- 

 ually increase in size, and often run together and form 

 large discolored patches. As the spots grow older they 

 become darker colored. AVhen the attack is serious 

 much injury may be accomplished in lessening the size 

 of the crop. This disease attacks both the sugar beets 

 and the ordinary varieties of cultivated beets. It has 

 also been found upon various varieties of mangolds. 



The affected tissues are shrunken by the action of 

 the fungus. By the aid of a lens one can see, here and 

 there on the diseased surfaces, the long, slender, cylin- 



