no Diseases of Truck Crops 



White Rot 

 Caused by Sclerotinia libertiana FcM. 



White rot, although fairly destructive, attacks only 

 isolated individual plants. It is prevalent in New 

 York, Ohio, Michigan, and Wisconsin. The same 

 disease also attacks cucionibers and numerous other 

 crops later mentioned. 



Symptoms. The disease usually appears during 

 continuous damp weather. It attacks the plant at 

 its stem end near the soil line. The infected part 

 becomes soft, watersoaked, bleached, and overrun by 

 a white weft of mycelial growth on the surface of the 

 epidermis. Later sclerotia or dark masses of fungal 

 threads appear irregularly within the pith and on the 

 surface of the diseased crown. Infected plants wUt, 

 topple over, and collapse. For a description of the 

 causal organisms, see lettuce, p. 143. 



Control. Spraying will not control this disease. 

 Whetzel and Rosenbaum' suggest that the soil be well 

 drained, and that plenty of ventilation be given the 

 shacks. The disease may also be eradicated in the 

 same manner as prescribed for lettuce drop, p. 144. 



Black Rot 



Caused by Sclerotinia panacis Rank. 



Black rot is not as prevalent as white rot above 



mentioned. The disease was named and described 



by Rankin. = 



' Whetzel, H. H., and Rosenbaum, J., U. S. Dept. of Agr., Bur. 

 of PI. Ind., Bui. 250 : 7-44, 1912. 



» Rankin, W. H., Phytopath. 2 : 28-31, 1,912. 



