86 STATE POMOLOGICAL SOCIETY. 



although we have searched for it in widely separated localities. 

 However, the fact that we have not found this disease does not 

 necessarily mean that it does not occur. 



The black-rot fungus, Sphacropsis malonim Pk, which is very 

 common here and is known to cause canker in other states has 

 been tested as to its effect on apple trees under Maine condi- 

 tions and has been found capable of doing great damage as it 

 spreads and kills the bark of regions several inches in length in 

 one season. The results with this fungus have been of value 

 also for use in comparison with some other fungi which have 

 been studied which have not been reported as causing disease in 

 other places. 



The bitter-rot fungus, Glomorella fructigena (Clinton) Sacc. 

 has been found in Maine for the first time. First in a decaying 

 apple which Professor Gardner secured at the Pomological meet- 

 ing last year and later from both apples and cankers from an 

 orchard in Oono. This fungus which does so much damage 

 in some of the great apple growing regions has not been found 

 to do very much damage here so far as we have been able to 

 determine. There are two forms of the .fungus, northern and 

 southern, which in some of their characters are quite distinct 

 and it seems from our study that the northern form is not so 

 active a parasite as the southern form. 



Besides these two which are usually regarded as the chief 

 fungi which cause canker, in the eastern part of the United 

 States, 8 other fungi have been used in making inoculations. In 

 making these inoculations small incisions have been made in the 

 branches of apple trees with a sterilized knife and then material 

 of the fungus from pure cultures has been placed in the in- 

 cisions. 



If the fungus which is used in making the inoculations is a 

 parasite, the mycelium grows and spreads rather rapidly, killing 

 the bark and in some cases girdling and killing the branch. The 

 bitter rot fungus and the black rot fungus are capable of killing 

 small branches in 3 or 4 weeks and may kill large branches in 

 a longer time. 



Of the other 8 fungi with which I have inoculated apple trees 

 during the past summer 2 have been found to be parasites. 

 When branches of young apple trees or small branches of large 

 trees, are inoculated with either of these fungi, the fungus 



