STRAWBERRY DISEASES 427 



BOTRYTIS-ROT 

 Caused by Botrytis sp. 



This disease is especially common and destructive in rainy 

 seasons. It appears to have an extensive range over the 

 country, occurring as far south as Louisiana and throughout 

 the northern strawberry-growing sections. It was especially 

 destructive over its entire range during the seasons of 1914, 

 1915 and 1916. It is reported as having caused a loss of 

 millions of dollars in the States of Mississippi and Louisiana 

 alone in 1914. Much of this loss resulted from the develop- 

 ment of the disease during shipment, though it was prevalent 

 and destructive in the field. 



Symptoms. 



All the above-ground parts are subject to the disease, but 

 the fruit and fruit-pedicels usually suffer most. Small green 

 fruits as well as mature and ripening berries may be affected. 

 The lesions usually appear first on the fruit as small, brown, 

 rotten spots. These rapidly involve the entire berry, from 

 which the fruit-pedicels become affected. Leaves and leaf- 

 petioles may show lesions, especially where they touch rotten 

 fruits. The injury is a dry, brown rot. The fruit shrivels 

 slightly, but retains its form. No exuding of juice is evident. 

 The diseased tissue turns brown, but remains firm. The berry 

 is finally coated with a dense growth of the spore stalks of the 

 pathogene, giving it a grayish brown, moldy appearance. 



Cause. 



The fungus responsible for this disease is a species of Botrytis, 

 possibly Botrytis cinerea. Another fungus Rhizopus nigricans( ?) 

 is also known to cause a rot of strawberry fruits which differs 

 strikingly from the Botrytis-rot in that there is a rapid loss of 

 juice from the fruit, giving it the name of " leak." This is accom- 

 panied by a collapse or flattening of the fruit. The Rhizopus 

 rot appears more commonly on berries in transportation. 



