CHAPTER IX 



Diseases of Celery 



IN the production of a small quantity of celery for 

 home use, plant diseases are not liable to cause 

 serious difficulty, but on a large scale where many 

 thousands of plants are grown together the chance 

 of infection is greater. In the commercial produc- 

 tion of celery it is necessary to observe every possi- 

 ble precaution to avoid loss from disease. Climatic 

 conditions play an important part in the control of 

 celery diseases. Owing to prevailing atmospheric 

 conditions, which favor the spread and development 

 of diseases, certain localities are not suited to the 

 production of celery, although the soil and market- 

 ing facilities may be ideal. In regions where celery 

 can ordinarily be grown without loss from diseases 

 there will occasionally be a season during which a 

 large portion of the crop will be affected. A warm, 

 humid atmosphere with sultry nights is liable to 

 develop diseases, but cool nights with clear atmos- 

 phere and bright sunshine during the day furnishes 

 ideal conditions for holding diseases in check. The 

 self-blanching varieties are more subject to the 

 attacks of diseases than the stronger-growing green 

 kinds. 



Damping. Immediately after the seedlings ap- 

 pear they are subject to attack from the disease 

 known as "damping," which causes the stem and 



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