190 Maine; agriculturai, e;xpe;rime;nt station. 1909. 



tion two weeks later, showed that of the 20 places inoculated, 

 in all except 2, which seemed doubtful, the fungus was grow- 

 ing and invading the uninjured tissue giving the bark a brown 

 color and a somewhat sunken appearance. Observations from 

 time to time through the summer showed that cankers were 

 developing. The bark was killed in regions 3 to 5 cm. in length 

 which in some cases had almost girdled the branch by Septem- 

 ber I. The fungus began to fruit on the dead bark in 3 to 4 

 weeks after the inoculations. The cankers shown in Fig. 20 

 were removed September i. The bark on the affected region 

 has a sunken appearance which comes about through the death 

 of the cambium cells so that the wood and bark cease to grow. 

 There was no dying of bark nor cankered appearance from 

 check incisions nor from inoculations made with Coniothyrium 

 pirina. 



June 24, 1909, inoculations were made on large branches of 

 Ben Davis and Baldwin trees. Coryneum, Sphcsropsis and 

 Phoma were used. 16 inoculations were made with Coryneum, 

 6 with Sphceropsis, and 11 with Phoma. 6 check incisions were 

 made. When these trees were examined September 30, it was 

 found that the checks were almost healed over by callus so 

 that the appearance was healthy. Sphceropsis had spread into 

 the uninjured tissue and had formed well marked cankers in 

 each case. Coryneum had spread to some extent in 14 of the 

 16 places but had almost healed over in the other 2. The 

 places inoculated with Phoma showed about the same as has 

 been described for Coryneum, one place was almost healed over 

 and the others had spread to some extent. One point of 

 importance which remains to be determined is the extent to 

 which these cankers caused by Coryneum will spread from year 

 to year. It is intended to keep some of this year's cankers 

 under observation so that this question may be answered. 



The results of the study of Coryneum foUicolum by means of 

 inoculations of living apple trees show that this fungus is a 

 parasite which is capable of doing great damage to young trees 

 and the small branches of older trees. It has also proved able 

 to keep wounds on larger branches from healing but it will be 

 necessary to keep such branches under observation for a longer 

 time to determine the extent of the injury. 



