47 
Fungous 
DiSHASiis 01-' Colorado Crop Plants 
(4) Spores of the fungus may be carried from field to field 
and even from farm to farm by soil or mud sticking to cultivating 
implements, horses’ feet, or -workmen’s shoes. 
Fruit Rot—Blossom End Rot. —This disease usually ap¬ 
pears on half-grown to full-grown tomatoes. It starts in at the 
blossom end as a slightly sunken, dry spot, which enlarges, darkens, 
and becomes rotted. The blossom end rot of tomato is considered 
to be a non-infectious disease. 
Control .— (i) The application of fungicides is not effective. 
(2) I'he appearance and progress of disease are favored by dry 
soil conditions. Keep an abundant and regular supply of moisture 
in the soil. 
SOME INJURIES NOT DUE TO FUNGI 
Sun Scald. —Sun scalding may be developed on the fruit or 
body O'f the tree, usually the latter. Cankers are produced on the 
body. The southwest side of the tree is most frequently injured. 
Young trees may be killed outright or much weakened. The sun’s 
rays may injure the trees either directly or by reflection from the 
hot dry soil, or water in irrigation ditches that are placed near the 
tree. Cankers produced in this manner may easily be mistaken for 
fungous troubles. 
Control .— (i) Newly planted trees should be headed low. 
(2) Protect trunks of newly planted trees. 
(a) By wrapping the trunks with burlap, paper, straw, wood 
veneer or wire netting. 
(b) By shading the trunk with a board placed on the south¬ 
west side. 
Frost Injury (Plate XVII). —Late spring frosts often in¬ 
jure the developing fruit and leaves. Frosted fruits become rus- 
seted either at the blossom or stem end, or very often in bands 
about the middle. Injured fruits may be deformed. “Frost blis¬ 
ters” may be produced on the leaves. Such leaves are crinkled, or 
have blisters produced by a separation of upper and lower sur¬ 
faces. The lo'wer surface of injured leaves usually has numerous 
cracks. Cankers may be produced on the southwest exposure of 
the tree, due to a freezing of sap and consequent killing of tissue. 
Such cankers may be mistaken for fungous troubles. 
Spray Injury. —Both foliage and fruit may be affected. In¬ 
jured fruits may be russeted or spotted. Leaf injury may be in the 
form of irregular, scattered, light brown spots, or the margin of 
the leaf may be browned, or in severe cases the entire leaf may be 
