4() 
Coi.oKADo Experiment Station 
The spores are scattered to healthy plants by wind and rain and 
irrigation water whei*e they germinate to produce new spots. 
On the stems the spots are similar to those on the leaves often 
occurring in clusters, uniting to form larger spots which may cover 
the greater portion of the stem. Such infected stalks soon turn 
brown and soft, finally dying and drying up. 
Late blight can be controlled by spraying with Bordeaux mix- 
ture (5-6-50). The first spray should be applied to the seed bed at 
the rate of thirty gallons per acre. If the disease is prevalent it 
would be advisable to spray the seed bed at least twice. After the 
Late blight of cefjsry. (After Coons and Levin.) 
plants are transplanted to the field, spraying should begin at the 
first appearance of blight. Spray once a month thereafter until the 
danger is past. In the field 50 to 100 gallons to the acre should be 
applied according to the size of the plants. Effective control de- 
pends upon the thoroughness with which the spraying is done. 
Early Blight (Cercospora apii) — This is also a leaf-spot disease 
but is not as serious as the late blight. Large irregular dead spots 
are formed on the leaves earliei* in the season. On account of the 
slight losses from early blight spraying is not considered profitable. 
Root-Rot (Rhizoctonia sp.) — Celery is often destroyed by a root 
rotting fungus which attacks the root at an early stage of develop- 
ment, causing them to decay with a moist soft rot. 
Crop rotation and the avoidance of over irrigation tend to reduce 
the amount of the trouble. 
