BLACKBERRY DISEASES 165 



Within a few hours after the opening of a flower-bud, the 

 ovaries become more or less whitish, due to the presence of 

 mycelium and spores which develop abundantly thereon. Spores 

 may be produced within forty-eight hours after a flower-bud 

 opens. These are carried chiefly by the wind ; it is believed 

 that the clothing of man, tools of various kinds, and insects are 

 also important carriers of the spores. 



The spores perchance alight on young buds that are being 

 formed for the following year. In the presence of moisture the 

 spores germinate and produce mycelium which lies dormant 

 in the buds throughout the winter. In the spring growth is 

 again resumed. 



Control. 



Spraying has not proved to be a satisfactory means of com- 

 bating this disease. The spores are produced at flowering and 

 during the period of growth of the fruit. Spraying at blossom- 

 ing might be objectionable, and any spraying done later in the 

 summer must not result in injury to, nor discoloration of, the 

 fruit. 



Handpicking deformed buds seems to be satisfactory. The 

 operation should begin as soon as the buds begin to open. As a 

 precautionary measure these buds should be destroyed, pref- 

 erably by fire. This method is very effective, on account of 

 the fact that the fungus does not go beyond the bud. The 

 grower cannot hope to completely eradicate the double-blossom 

 pathogene, yet the operation is said to be profitable. 



In southern regions all canes are cut at the ground immedi- 

 ately after the crop is harvested. This is considered an im- 

 portant operation in dewberry-culture on account of its value 

 in the control of anthracnose and double-blossom. 



REFERENCES 



Cook, M. T. The double blossom of the dewberry. Delaware Agr. 

 Exp. Sta. Bui. 93 : 1-12. 1911. 



