428 MANUAL OF FRUIT DISEASES 



The spores produced in great abundance from the spore 

 stalks on diseased fruits are scattered through the berry patch 

 or field, and many fruits become inoculated. When moisture 

 is abundant and retained on the plants through the day, the 

 spores readily germinate. Whether the germtubes can pene- 

 trate the uninjured surface of fruits is not certain, though this 

 is probable. The mycelium spreads rapidly and profusely 

 throughout the tissues of the fruit, between and through the 

 cells, which are rapidly killed. The fungus feeds upon the 

 substance of the invaded tissues and soon sends forth great 

 numbers of brown stalks, branched at the tips and bearing 

 thereon many grape-like bunches of oval thin- walled spores. 

 These spores are readily scattered by the wind and cause new 

 infections. How this fungus winters is not certain, though 

 probably by means of sclerotia. Sclerotia are black tuber-like 

 bodies of densely interwoven mycelium which are formed 

 by all species of Botrytis, in dead host-debris. They pass 

 the winter in a dormant condition, and germinate the following 

 spring, producing tufts of spore stalks bearing spores like those 

 already described. These spores initiate new infections. 



Control. 



Little definite information based upon experimental data 

 or experience can be offered. Losses in shipment may be re- 

 duced by careful sorting out of all diseased or injured berries. 

 Discarded fruit should not be allowed to accumulate about the 

 packing house, but should be burned or buried daily. Field 

 losses will be much reduced by growing the plants well apart 

 in order to afford a maximum of light and air. 



REFERENCES 



Stevens, F. L. A destructive strawberry disease. Science n. s. 



39 : 949-950. 1914. 

 Stevens, N. E. Pathological histology of strawberries affected by 



species of Botrytis and Rhizopus. Jour. Agr. Res. 6 : 361-366. 



1916. 



