SCALD. 13 



contrary to this theory. They concluded from their trials with 

 several fertilizers that the blight depended largely upon the vitality 

 of the vines. Plats treated with phosphates showed least blight. 

 In conclusion they say : " The agent of destruction of these blossoms 

 is probably a bacterial or fungus growth which takes place only 

 under a devitalized or weakened condition.'' Having had no oppor- 

 tunity to make a study of the blight, or blast, in Wisconsin, we are 

 unable to say how much of it may be due to Guignardia vaccinii, 

 which produces the blast, or blight, in the East. From the fact that 

 this fungus occurs in Wisconsin and destroys more or less of the 

 fruit, it is highly probable that some of the blight, or blast, is also 

 caused by it. The " blossom blight " is also mentioned by Whitson, 

 Sandsten, Haskins, and Ramsey. 10 They state that a treatment for 

 blight of three applications of Bordeaux mixture produced an 

 increase of 30 per cent in the crop of fruit over that on adjacent 

 vines not treated. This would seem to indicate that the disease is of 

 a fungous nature. 



SCALD. 



The term u scald " is one which has been in general use among 

 the New Jersey cranberry growers for a long time. It originated 

 as a result of a view previously held by many growers that the 

 softening of the diseased fruit was due to an actual scalding of the 

 berry, caused by the hot sunshine when the berries were wet. 



A condition somewhat resembling the effect of the fungus does 

 sometimes occur when berries have been overflowed and covered 

 with water for half a day or more during hot weather, but injury 

 of this kind is infrequent and unimportant. 



The first indication of the attack of the scald fungus upon the 

 cranberry is the appearance of a minute, light-colored, watery spot 

 upon its surface. This, under favorable conditions, rapidly spreads, 

 usually in a concentric manner, until finally the whole berry becomes 

 soft (PI. I). Frequently the diseased area is marked by con- 

 centric dark-colored rings. This, however, is not always the case, 

 and is not especially characteristic of this disease, as it sometimes 

 occurs in the case of the cranberry rot. In very rare instances only 

 a small, light-colored sunken spot is produced upon the berry, the 

 fungus by some unknown cause having been retarded or entirely pre- 

 vented from further development. In such cases we occasionally find 

 the pycnidia of the scald fungus present, as illustrated by Doctor Hal- 

 sted 10 in his work on cranberry scald. Ordinarily, however, there 

 is no indication on the surface of the fruit of the presence of a 

 fungus, except for occasional dark blotches or brownish zones, as 

 mentioned above. Berries which are attacked before they are half 

 grown usually shrivel up and become blackened and covered with 

 no 



