556 



Sclerotium Disease. 



[dec, 



owing to decay of the host-plant, they fall to the ground and 

 produce spores which infect a new crop. 



The fruit produced by sclerotia may either be of the Botrytiz 



Eig. i. — Portion of a potato haulm with the Bolrylis form of fruit starting fromi 

 the ground line. 



Fig. 2. — Portion of a potato haulm split open, showing black sclerotia inside. 

 Eig. 3. — An onion with sclerotia attached to the scales. 

 Fig. 4. — The two forms of fruit growing from sclerotia. 



form, or less frequently resemble a slender, long-stalked wine- 

 glass of a clear brown colour, 



Rotting of turnips and swedes, and " yellow blight " of potatoes 

 are instances of the injury caused by this disease. 



In bulbous plants the sclerotia are formed in the bulb. 



The great prevalence of this disease is due to plants con- 

 taining sclerotia being left on the land. Placing such diseased 



