126 Diseases of Greenhouse Crops 



On potatoes a liberal growth is produced with no 

 odor and no browning of substance. 



Control. Before planting, cauliflower seed should 

 be disinfected for fifteen minutes in a solution of 

 ^ pint of pure (40%) formaldehyde diluted in 

 seven gallons of water. In making the seed bed, 

 manure known to be free from cabbage refuse should 

 be used. All insect pests should be kept in check 

 by spraying with arsenate of lead. The disease can- 

 not be controlled by merely cutting off diseased 

 foliage. If anything, this operation aggravates the 

 trouble. Diseased plants should be pulled out and 

 destroyed. 



Soft Rot 



Caused by Bacillus caratovorus Jones. 



Soft rot, although a field trouble, causes consid- 

 erable damage to greenhouse cauliflower. 



Symptoms. The disease is characterized by a soft, 

 mushy to slimy decay of the entire plant. The dis- 

 ease works very rapidly under favorable conditions 

 of moisture and temperature. The causal organism 

 can gain entrance only through a wound or bruise. 



The Organism. Soft Rot is caused by a bacillus 

 that is rod-shaped, of varying length, and usually 

 formed in chains. It moves about by peritrichous 

 flagella. It completely liquefies gelatine in about 

 six days. Gas is produced with a majority of str^ns. 



Control. Diseased plants should be destroyed by 

 fire. To check further spread, water should be with- 

 held and plenty of ventilation allowed. During 



