272 Bulletin 145. 



and Virginia, and pear leaves from Alabama show spots characteristic 

 of this disease, although the immature condition of the fungus renders 

 a definite determination difficult. Nevertheless, from the above we 

 are assured of its general distribution in the eastern states, and in 

 many places it is the most abundant leaf fungus of the pear. 



3. Occurrence in Orchards. 



By far the majority of observations as to distribution were made 

 upoji orchard trees, since these are generally mure accessible. For- 

 tunately, there is no evidence to show that this disease ever attacks 

 the fruit, so that there is little danger of losing a growing crop. The 

 foliage of susceptible varieties, however, is often greatly injured by 

 midsummer, and many trees are partially defoliated in August, At 

 Black Hook I observed a number of yard pear trees more than half 

 defoliated on June 1 7. At Cayuga large blocks of several varieties were 

 considerably defoliated by the latter part of August, but during the 

 midsummer the leaves were only spotted and somewhat discolored. 

 Under ordinary circumstances, a number of varieties are so slightly 

 injured that the defoliation is scarcely evident before the appearance 

 of frost, unless there are adjacent resistant varieties for comparison. At 

 any rate, many varieties suffer more or less, and even though affected 

 leaves should adhere until after the summer pears are gathered, the 

 injury to the leaf throughout the summer and its fall a month or more 

 before the normal time are sufficient injuries to demand our attention. 

 We must assume that the vigor of the tree is thus reduced for the per- 

 fection of its product another year. Only a series of experiments 

 through a period of years could determine accurately the extent of such 

 injuries. 



There has been collected a considerable amount of data as to varie- 

 ties affected, but mostly in small orchards. Such matters are also liable 

 to great variation, and I present a general account merely for the sug- 

 gestion it may give. In this connection notes on a single orchard are 

 valuable for the comparison of varieties, as far as they go. In the 

 orchard of Mr. H. S. Coleman, of Geneva, no spraying was done 

 during '96. In round numbers there were about one thousand trees, 

 distributed as to number in yariety as mentioned below, In order of 



