New York Agricultural Experlmext Station. 201 



now grown cliiefly by topgrafting on varieties not subject to 

 sunseald. 



Cytospora. — Plum trunks and branches affected by sunseald 

 are almost invariably infested by a species of Cytospora. In the 

 case of a recent injury where the bark is not yet loosened the 

 Cytospora is usually found in the sclerotium-like stage described 

 on page 194. The Cytospora i)imples are very abundant and often 

 oecur within half an inch of the living bark. This condition is 

 best O'beerved on the larger branches where the affected areas are 

 depressed and the boundary between the living and dead bark 

 plainly marked. Such areas on the branches usually have open 

 connection with the sunseald injury on the trunk although occa- 

 sionally an isolated one is found; but in nearly all cases they are 

 covered with Cytospora. On injuries of longer standing the 

 Cytospora pimples have white tops and are more likely to be 

 found fruiting. In the older injuries there are also occasionally 

 found perithecia of Talsa, the mature form of Cytospora. 



The branches of Japan plums sometimes show isolated areas a 

 few inches long on which the bark is dead and shrunken to the 

 wood. If the branch is a small one it is likely to be slightly 

 enlarged at the point of injury. Such injuries are often called 

 cankers. They generally bear Cytospora pimples. 



From a canker on Japan plum we obtained a pure culture of 

 the Cytospora and inoculated it into six branches of Japan plum 

 — three one-year-old branches and three of the present season's 

 growth. They were inoeulated by first abrading the bark, insert- 

 ing a bit of fungus in the wound and finally covering the point 

 of inoeulation with grafting wax. The inoculations were made 

 July 6 and at the same time two checks were prepared on one- 

 year-old branches. In a few days gum began to exude from the 

 inoculations and by the close of the season there were good can- 

 kers at all six points of inoculation, while on the checks there 

 was nothing abnormal, not even an exudation of gum. 



On July 21 the same Cytospora was inoculated into five peach 

 shoots (variety Foster) of the present season's growth in the 

 same manner that the plum branches were inoculated. There 



