1903.] PUBLIC DOCUMENT — No. 33. 27 



EEPOKT OF THE . BOTANISTS. 



GEORGE E. STONE, RALPH E. SMITH. 



Plant Diseases in 1902. 

 Diseases affecting cultivated plants have, as usual, caused 

 more or less damage during the past season. The following 

 pages describe briefly the occurrence of the most important. 



Peach-leaf Ourl {Exoascus deformans) . 

 This fungus was rather more prevalent than usual early in 

 the season. Its effects were most noticeable upon young 

 trees, particularly upon Elberta and Crosby, these varieties 

 being; attacked to the exclusion of others in the same orchards. 

 Though very destructive in many portions of the country, it 

 is not commonly a serious one in Massachusetts. 



Apple-leaf Spot. 

 One of the most noticeable troubles of the season has 

 been the injury to apple foliage caused by frost, which is 

 described elsewhere in this report.' Many trees, after the 

 spotting and yellowing of the leaves early in the season, 

 were quite denuded by midsummer. Well-cared-for trees 

 were not often affected, so that the actual damage from this 

 source was probably very slight. 



Sycamore Bliglit {Glceosporium nervisequum) . 

 This disease was, as usual, verj^ severe, causing the fall 

 of almost all the leaves on sycamore trees during .Tune and 

 July. 



Strawberry Root Rot. 



This apparently new trouble of the strawberry plant (see 

 p. 34) was much complained of in new beds set out this 

 season. 



