Fungous Diseases oe Colorado Crop Plants 17 
Control .— (i) Use seed from healthy pods only, preferably 
those grown on fields known to be free of the disease. 
(2) Burn infected material. 
(3) Rotation of crops is important. 
(4) Spray with 4-5-50 Bordeaux first, as soon as the plants 
are up, then about ten to fourteen days later, and again when the 
pods are forming. 
BEET. 
Root Rot {Rhizoctonia ).—The outer leaves are first attacked 
at the base, turn black and droop. The disease spreads into the 
crown of the beet, which turns brown, cracks, and in time may rot 
away. The trouble spreads rapidly from plant to plant. Young 
plants are also frequently attacked by the root rot fungus. 
Control .— (i) Keep soil Avell aired by good cultivation, 
(2) Rotate crops. 
Sort Rot. —This is a bacterial disease. The lower end of the 
root decays, the rotted portion being honeycombed. The cavities of 
this portion are filled with a rather sticky, colorless, sour-smelling 
liquid. The upper part of the root, the crown, and leaves, are not 
affected, and hence the plant maintains a normal color and form 
above ground. Young plants are not attacked seriously. 
Control .— (i) It is useless to spray. 
(2) A wet, poorly drained soil favors the development of dis¬ 
ease. Improve soil conditions. 
Lear Spot. —This disease attacks the outer, older leaves first. 
The youngest leaves in the center rarely show the spots, and the 
beet plant is seldom killed. At first the spots are tiny white points 
scattered over the leaf surface. They gradually increase in size, 
become round, show a distinct line between diseased and healthy 
portion, and assume a brown color frequently tinged with a red- 
brown or purple. Still older spots assume an ash-gray center. 
They are usually distinct, but may become numerous enough to 
cover the entire leaf. Such a leaf blackens and dies. As the older 
leaves die, new leaves are formed at the center of the crown. Hence, 
there is formed an elongated crown with tufts of small green leaves 
at the top. 
Control .— (i) Deep fall plowing and crop rotation is the most 
satisfactory method of control. 
2. Spraying with Bordeaux mixture, 4-5-50 formula, will 
almost perfectly control the disease, but it is seldom practical. The 
time for spraying is indicated by the first appearance of the disease. 
The leaves must be covered thoroughly on both sides. 
