18 CRANBERRY DISEASES. 



The fifth successful culture from diseased berries was made May 

 10, 1904. The berries Avere received from Cranmoor, Wis. They 

 were softened and shriveled and showed definite black spots 011 the 

 surface. After washing and soaking for three-fourths of an hour 

 in corrosive-sublimate solution, sections of the diseased portion, in- 

 cluding the skin, were transferred to large tubes of sterilized corn 

 meal. About one month later ascogenous perithecia of Guignardia 

 were found in this culture. Several other cultures made at the same 

 time upon the same culture medium and from fruit having the same 

 appearance produced only pycnidia. Transfers made from cultures 

 producing asci to sterile potato cylinders have produced the ascoge- 

 nous form as quickly and 'abundantly as when grown on corn meal. 



Besides the successful cultures just described, which have been made 

 from diseased berries, we have, in three instances, obtained from 

 cranberry leaves pure cultures bearing both pycnidia and asci. 



On March 23, 1905, cultures were made by placing in flasks of 

 sterile corn meal leaves which had been first soaked for about onp 

 hour in a 1 to 500 solution of corrosive sublimate and then cut in 

 two pieces. These leaves were taken from vines which had borne 

 very badly scalded fruit during the previous season. The vines were 

 collected on November 29, 1904, and kept in an ice box from that 

 time until the cultures were made. The leaves were of 1903 growth 

 and were to all external appearances healthy and free from fungi. 

 Leaves taken from this collection in March, 1906, still produced plenty 

 of good pycnidia and ascogenous perithecia. The course of develop- 

 ment of the fungus in these cultures was identical with that described 

 in the other cases. Pycnidia were produced in abundance in about 

 fifteen days, and at the end of twenty-nine days ascogenous perithecia 

 were found in three of the cultures. 



From these original cultures many others have been made by trans- 

 fer. Four generations have been grown in this way, producing both 

 pycnospores and ascospores in each. After this the fungus appeared 

 to have lost its vitality and did not grow well. In other cases it 

 developed both spore forms for one or two generations only. 



The fresh pycnospores of this fungus germinate and grow readily 

 in water, in a dilute solution of sugar and water, and in ordinary 

 culture media. Spores placed in a drop culture of sugar water in the 

 laboratory began to show signs of germination at the end of two days. 

 The germ tube usually arises from the side of the pycnospore, first 

 forming a slight enlargement, which rapidly elongates into a germ 

 tube and soon begins to branch (PL II, figs. 4 to 9). At the end of 

 four days many of the germ tubes have attained considerable length. 

 The tube occasionally arises from the basal end of the spore (PL II, 

 fig. 6), but we have never seen it arise from the apical end, where the 

 no 



