43 6 CONNECTICUT EXPERIMENT STATION REPORT, IQI2. 



the wounds inoculated with E. gyrosa, sometimes this injured 

 bark was a little more extensive than with the checks, which 

 indicated a slight but futile attempt at parasitism. Occasionally, 

 on this dead bark and exposed wood, a slight fruiting growth 

 of the fungus as a saprophyte was formed. 



With var. parasitica, however, the bark was gradually killed 

 in an increasing area surrounding the point of inoculation, and 

 this had a more or less irregular outline, spreading faster in 

 some directions than in otners. Eventually the whole stem or 

 limb was encircled, if the inoculation was made early in the 

 season (see Plate XXV a). At the inoculation point a callus of 

 young tissue often developed, and the vitality of this was greater 

 than that of the older tissues, since it often remained healthy, 

 until, being entirely surrounded by dead tissues, it died as much 

 from adverse nutritive conditions as from the direct action of 

 the fungus (Plate XXV b). 



After the cankers attained some size, their reddish dead 

 bark often became cracked, and the Cytospora fruiting stage 

 appeared in more or less abundance. An examination of the 

 inoculations as late as the last of December, however, failed 

 to show that the asco-stage had developed on any of them. 

 Whether this means that ordinarily the mature fruiting stage 

 does not appear until the second season, we do not know, but 

 it shows that sometimes this is the case. The inoculations made 

 early in May on the chestnut sprouts one to two inches in 

 diameter entirely girdled these for six to eight inches, forming 

 very evident cankers, but not always with a conspicuous develop- 

 ment of conidial spores. 



Hosts Inoculated. In the inoculation tests we used seedlings 

 and sprouts of both chestnuts and oaks. Considering first only 

 the chestnut hosts, we found that, as a rule, the variety para- 

 sitica could be more easily inoculated into the sprouts than into 

 the seedlings, and that on the sprouts the blight made a larger 

 growth in the same length of time. This greater development 

 might in part be due to the larger size of the sprouts, which 

 varied from about one-half to one and one-half inches in 

 diameter, while the seedlings were only about one-quarter to 

 three-quarters of an inch in diameter. Out of a total of 177 

 inoculations with cultures originally from chestnut made on 

 chestnut seedlings, 91, or 51 per cent., took, as compared with 



