HYPERTROPHY. 35 



but the exact time and manner lias not yet been determined for want 

 of plants known to be entirely free from disease. 



TREATMENT. 



From the beneficial results of spraying cranberries ^Yhere this dis- 

 ease was known to be present and also from the success obtained in 

 preventing other diseases caused by similar fungi, such as the bitter- 

 rot fungus of the a])ple.^" it appears probable that thoi'ough spray- 

 ing Avith r>or(leaux mixture will i)r()ve a satisfactory treatment. 

 The disease so far as now known is always associated Avith scald or 

 rot, and the treatment reconnnended for those diseases will be suffi- 

 cient for this. 



HYPERTROPHY. 



The fungus {Exohasidium oxycocci Kostr.) causing hypertrophy is 

 only known at present from Massachusetts. In IDOG it destroyed a 

 considerable part of the croj) on several cranberry meadows in that 

 State and caused considerable alarm. It is apparently somewhat 

 erratic in its behavior. On one meadow it attacked almost every 

 plant on a part of the bog, while some other portions were almost free 

 from it. The variety known as Matthews seemed to be especially 

 susceptible to the disease. 



The disease first makes its appearance on flooded bogs soon after 

 the water has been removed in the spring, Avhich is usually about the 

 middle of May or a little later. The axillary leaf buds, which usually 

 remain dormant, are attacked by the disease and produce short shoots 

 with rather close, enlarged, swollen, and distorted leaves which are 

 pink or light rose colored (PI. VII, C and D). The colored hyper- 

 trophied leaves, being close together, bear a slight superficial resem- 

 blance to a flower of some sort. This appearance has led some per- 

 sons to call these diseased shoots " false blossoms." This is mislead- 

 ing, as it suggests some reference to the flowers of the cranberry, 

 which are not included in this peculiar malformation. 



Most of the affected plants are attacked before the blossoms have 

 developed, thus preventing the production of fruit. Shoots Avhose 

 buds are attacked later in the season after the blossoms have opened 

 or fallen (PI. VII, D) also usually fail to develop fruit, as the vital- 

 ity of the shoot is apparently exhausted by the fungus. Besides the 

 fruit-bearing shoots, ordinary vegetative shoots or runners are also 

 affected in the same manner (PI. VII, C). 



No opportunity has been afforded to examine plants which had 

 suffered from this disease the previous year, but the injury to the 

 affected plants and the lowering of their vitality are so evident that 

 the production of fruit the succeeding season would probably be far 

 below normal even though the disease did not recur upon the plants. 



110 



