Leaf Curl and Plum Pockets. 349 



with the fungus on the leaves of P. serotina I,, which I have re- 

 ferred to E. varius n. sp. I would therefore provisionally refer 

 it to that species. 



CONCLUSIONS. 



It is to be regretted that definite and conclusive experiments 

 have not yet been made concerning the treatment and control of 

 the diseases caused by the various species of the Exoascece, so 

 that this information, which is most desired by fruit growers could 

 be here confidently placed before them. It is hoped, however, 

 that this contribution will give those interested a greater familiar- 

 ity with the characteristics of the deformed leaves, fruits, and 

 branches caused by this group of parasitic fungi and that this will 

 lead to a more intelligent line of experimentation. 



It should be remembered that the species possess a perennial 

 mycelium which lives in the buds or branches of the trees, during 

 the winter months, of plants which once have become infected. 

 That a tree once affected is likely to show the disease more or less 

 every year. Climatic conditions probably influence a greater or 

 less injury from year to year, so that in some years little of the 

 trouble may be observed when in other years it is more common. 

 This has led some to suppose that the fungi are not perennial, 

 but that a fresh infection each year is caused by the spores only. 

 This is a mistake. There is abundant evidence from the results 

 of several investigators to show that the mycelium is perennial, 

 for it has been found during the winter months, and in the spring 

 has been traced as it grows from the buds or branches into the 

 young leaves or fruits. It is quite possible that one source of the 

 original infection of trees is from the attacks of spores. I have 

 several times attempted to inoculate healthy peach trees, or un- 

 affected ones, from the spores taken from freshly mature specimens 

 on affected trees. This I attempted at Auburn, Ala. Not only 

 were spores sown on the young leaves and buds, but pieces of 

 the leaves containing mature spores, and others containing the 

 mycelium only were inserted into a slit in young buds and in the 

 young branches near buds. In no case did any sign of the dis- 

 ease appear even after three years. Several of these incisions 



