276 Report of the Department of Botany of the 



of the disease from year to year and more vines were dead or nearly 

 so at the conclusion of the work in 1913. July 19, 1910, one of the 

 vines in this row showed a marked sunken area near the saw cut 

 which was covered with pycnidia. When placed in a moist chamber 

 for a few days spores oozed from the pycnidia and a pure culture 

 of Cryptosporella was readily obtained. 



Third series. — On July 12, 1909, thirty-five vines (Worden) 

 were inoculated as above, using spores and mycelium of the fungus 

 from pure culture (3229, isolated from a diseased Concord stem 

 July 1, 1909). On July 1, 1910, all the vines showed a copious flow 

 of gum at the point of inoculation but there was no other apparent 

 effect. June 27, 1911, the sunken areas at the point of inoculation 

 were conspicuous. One vine examined showed dead wood nearly 

 to the heart of the trunk. July 3, 1912, a number of the vines showed 

 marked symptoms of the disease and one vine was entirely dead. 

 July 10, 1913, eleven vines were dead or nearly so, five were in 

 fair condition and eighteen were still apparently healthy. July 19, 

 1910, one vine was cut off and examined. The extent of the infec- 

 tion is shown in Fig. 13. Direct transfers of diseased tissue to sterile 

 grape stems gave pure cultures of the fungus. A similar isolation 

 was made October 29, 1913, from another of these vines with the 

 same result. 



inoculation by incision on shoots. 



July 1, 1909, each bearing shoot on thirty vines was inoculated 

 by making a gash with a scalpel near the base and inserting mycelium 

 and spores of the fungus (3216, isolated July 23, 1908, from vine 

 23 of Table I, and in its fourth generation in culture). July 1, 

 1910, gumming was observed about the majority of the incisions. 

 One cane examined showed a blackening of the tissue for an inch or 

 more from the point of inoculation. In the case of incisions made 

 as a check a slight blackening may appear later, but does not extend 

 any considerable distance from the original point of incision. 



July 10, 1910, the fungus was readily recovered from two of the 

 inoculated canes. 



April 26, 1912, a number of the inoculated canes (now arms) were 

 removed and pure cultures of the fungus obtained by direct transfer 

 of diseased tissue. Later in the season, July 3, practically every 

 vine showed marked symptoms of the disease and three of the arms 

 trimmed and tied up were found to be dead. July 10, 1913, thirty- 



