l88 MAINE AGRICULTURAIv ElXPERIME^NT STATION. I909. 



were placed in the incision. These places were then wrapped 

 in moist absorbent cotton to prevent drying out. 



One week after the time of inoculation, it could be noted that 

 there was some evidence of growth and at the end of 10 days 

 there was a region of dead sunken bark around each of the 

 inoculated places. The fungus continued to invade the healthy 

 tissue to such an extent that May 20, 16 days after the inocula- 

 tion, the branches were almost girdled in some places and com- 

 pletely girdled in others. The regions injured by the fungus 

 were 2 to 7 cm. in lengths The leaves on the, girdled 

 branches were wilted while those on uninoculated branches were 

 green as shown in Fig. 18. Fig. 19 shows two of the cankers 

 enlarged. On the dead bark little black pustules were observed 

 which on examination proved to be the fruiting pustules of 

 Coryneum foliicolum. Sections through these pustules were 

 prepared • from which Figs. 28 and 29 were taken. 



A piece of one canker was cut ofif and placed in i-iooo cor- 

 rosive sublimate for two minutes after which it was thoroughly 

 washed with sterile distilled water. Eight pieces were cut from 

 this canker at various places with a sterile scalpel amd placed 

 in plates of prune agar. After one week, the plates were 

 examined and it was found that pure cultures of- Coryneum had 

 grown from 5 of the pieces while the others showed Coryneum 

 which was accompanied in one case by Alternaria, in another 

 by Coniofhyrium pirina (Sacc.) Sheldon and in the third by 

 what is probably a species of Torula. 



Two of the one-year-old trees in the greenhouse were inocu- 

 lated at 4 places each May 13, and two others in 4 places each 

 May 18, the same method being followed that was used in the 

 first set of inoculations. One check incision was made in each 

 of the 4 trees. All of the places which were inoculated devel- 

 oped well marked cankers. The small branches were girdled 

 and killed in from 2 to 4 weeks but inoculations on the main 

 stem did not girdle and kill the tree in either case although 

 considerable areas of bark were killed. The check incisions to 

 which no fungus was added soon began to heal over by the 

 formation of callus. 



For comparison, inoculations were made May 13, with 

 Sphceropsis malorum on 5 trees which were kept under the same 

 conditions as those which were used for Coryneum foliicolum. 



