78 



CELERY CULTURE 



root to decay near the surface of the soil. Damping 

 may be attributed to any of the following fungi : 

 Sclerotinia libcriiaiia, Rhizoctonia, and Fusarium. 

 The greatest liability of injury from this source is 

 during the first two weeks after the seedlings appear. 

 Plenty of light, care in watering, and thorough ven- 

 tilation are the only satisfactory methods of pre- 

 venting loss from damping. If the plant bed is in 

 the open ground it may be necessary to shelter it 

 from continuous rains, and a light dusting with dry 

 Bordeaux mixture may prove beneficial. As a pre- 

 caution against damping, seedlings that are in trays 

 may be subwatered by setting each tray for a few 

 minutes in a shallow trough, allowing the water to 

 enter the bottom of the tray through the drainage 

 holes and moistening the soil without wetting the 

 surface. 



Blight^ — The disease of celery known as "blight" 

 is caused by Ccrcospora apii, which attacks the 

 leaves of the plants, appearing as grayish spots 

 which turn brown or to a burned appearance within 

 a few days. The commercial celery crop is greatly 

 injured by the blight and the disease is liable to 

 appear at any time after the plants are set in the 

 open field. The blight generally appears first upon 

 the outside leaves and rapidly spreads until the 

 whole plant is infected. Warm days and nights 

 with a high degree of moisture in the atmosphere 

 are conditions suitable to the development of blight. 

 Cool nights and a dry atmosphere will generally 



lU. S. Dept. of Agr., Farmers' Bui. No. 148. 



