PLANT DISEASES IN I908. 19- 



in the crotches and showed conspicuous dead areas on the hmbs 

 and smaller portions of the trunks. In the Woods orchard a 

 solid acre of Spys about 8 years old which were perfectly 

 healthy in the fall showed in the spring every tree, either killed 

 or so badly injured that they put forth a few leaves and then 

 died. Crotch injury and frost patches were a very constant 

 occurrence on these trees. An adjoining acre of trees 15 or 

 more years old, largely Mildings with some Russian varieties 

 and a few pear trees, lost only a comparatively small number, 

 but here again the crotch injury was very prevalent, more so 

 than frost patches on the limbs. A very noticeable fact was 

 that in this part of the orchard whole limbs or parts of the tree 

 were killed only on the northwest side of the trees where most 

 exposed to the cold winds. The bark on the northwest side 

 of the trunks on nearly all of the trees in the northern row was 

 entirely killed, while only a few like instances could be found 

 in the remainder of this block of trees. 



Repeated attempts to isolate B. amylovorus from the injured 

 crotches or limb patches only resulted in failure. Neither was 

 there any constant association of a fungus with the patches, 

 although various fungi, largely sapophytes, began to appear in 

 the injured areas as the season progressed. The writer is per- 

 fectly familiar with the appearance of bacterial blight of the 

 pear, but after spending two and one-half years in Maine, has 

 yet to see a case of pear blight in the State, and no specimens 

 of this disease have been sent in to the Station during that time. 

 This indicates that while the disease without doubt occurs in the 

 State it is by no means common. 



At Orono all pear trees were killed by the winter but at Dov r 

 there were several living pear trees growing along side of the 

 crotch-injured trees. These showed no bacterial blight during 

 the past two seasons which would not have been the case had 

 the organism been present in sufficient quantities to cause the 

 amount of crotch injury which appeared in the apple orchard. 



Since the crotch injury was coincident and almost invariably 

 associated with the winter-killing resulting from the severe 

 winter of 1906-07 and since it would seem that all other prob- 

 able causes are eliminated it is fair to assume that it was in 

 some way brought about by the same adverse weather condi- 



