264 The Spraying of Plants. 



BEAN, LIMA. 

 FUNGOUS DISEASES. 



Blight (Phytophthora Phaseoli, Thaxter). Description. This 

 fungus attacks the young leaves and stems, and also the pods. 

 Tt generally appears during August and September, and covers 

 the affected parts with a dense, white covering. 



Treatment. Spray the plants with some clear copper com- 

 pound before the season when the disease generally first appears. 

 Two or three applications should protect the vines. 



BEET. 



Leaf Spot (Cercospora beticola, Sacc.). Description. u The 

 common name well describes the general appearance of the beet 

 leaves infested with this Cercospora,ior they are at first more or 

 less covered with small light or ashy spots, which later often 

 become holes by the disappearance of the tissue previously 

 killed by the fungus. . . . Full-sized leaves often become 

 mutilated, and sometimes scarcely more than the framework 

 remains." * The spots are at first surrounded by a band of red 

 or purple (Fig. 47). The disease is more or less prevalent 

 throughout the summer months. 



Treatment. The trouble may be controlled by the use 1 of 

 fungicides, but as beet foliage is easily injured, the safest one 

 to use is the Bordeaux mixture. This may be used of the 

 normal strength, or even more dilute. The first applications 

 should be made about the middle of June or early in July, de- 

 pending upon the latitude and the season. The foliage should 

 thereafter be kept covered by the material. 



Root Rot (Phyllosticta, sp.). Description. The fungus caus- 

 ing root rot of beets is particularly serious after the roots are 

 stored. The affected parts shrink slightly, turn black, yet 

 remain quite firm. The leaves appear to be affected by the 

 same fungus, its presence causing the formation of circular 

 spots, sometimes half an inch in diameter. The diseased tissue 

 dies and soon cracks. 



Treatment. The foliage should be well protected by the Bor- 



1 Halsted, .2V. J. Agric. fijcp. Ma-. 1895, Bull. 107, 8. 



