Notes on Certain Diseases of Plants 237 



properly and in June of the same year, when this photograph 

 was taken, the death of the tree was evidently imminent. 

 Below ground there are no signs of galls accompanying this 

 trouble, but just above the surface the trunk is swollen, often 

 to twice its normal size, and the bark is rough and cracked. 

 The wood of this portion is soft, almost spongy in places, and 

 more or less decayed, so that the trunk is greatly weakened 

 and frequently breaks under the force of the wind. Imme- 

 diately below the swollen portion the trunk is contracted, 

 forming a sort of collar, and it is here that the break occurs. 

 A tree which still appears fairly vigorous may sometimes be 

 broken off at this point merely by a strong push. 



It is a peculiarly sporadic disease; that is, one orchard may 

 show scores of trees affected with it, while an adjoining orchard 

 exhibits no trace of it. Even in the same orchard the diseased 

 area may be distinctly limited, although nearly every tree in 

 that area has succumbed. In one orchard which I visited the 

 remains of an old stone wall divided the diseased trees from 

 the healthy ones. The trees were all of the same age and 

 variety and had received the same culture, yet on one side of 

 the wall hardly a tree was standing, while on the other not a 

 single tree was affected. Practically nothing has yet been 

 done toward determining the nature and cause of this disease. 

 Certain facts indicate that it may be due to an organism identi- 

 cal with or similar to that which induces crown -gall. Diseased 

 material has been preserved for study, but meanwhile it is of 

 the utmost importance that peach -growers should watch for 

 the first signs of this new trouble and report its appearance at 

 once to the Experiment Station or to me personally. The total 

 destruction of the diseased trees by fire is the only safe proceed- 

 ing at present. 



Cane-Gall of Raspberry. — This disease, figured in Plate 

 4, has been sent in to me from several localities in the 

 state during the past year. The illustration shows admirably 

 the characteristic symptoms of the disease, — rough, whitish 

 masses of tissue of a cheesy consistency bursting through the 

 bark. It is unlike any disease of raspberries with which I am 

 acquainted, but the general character of the diseased tissue 

 recalls that of the galls formed sometimes on the roots of 



