DISEASES OF THE CHESTNUT AND OTHER TREES 91 



two infections on the two sections taken from the stem were the 

 only breaks in the bark found by the spores last summer. They 

 show very well the characteristic appearance of the bark at this 

 €arly stage of the disease. 



At the top of the tree where the disease is older the bark is 

 sunken and reddish-brown in color and broken up by the pustules 

 or small eruptions from which the spores escape; but on the two 

 later infections of the trunk started last summer by the washing 

 down of the spores the bark is not yet sunken, is of a dull orange 

 or flame color, and has not pushed up pustules. If these diseased 

 places are cut into with a knife the dark brown part shows the 

 dead bark and the light brown part the mycelium of the fungus 

 itself. This part filled with the mycelium of the fungus is practi- 

 cally the same as the "spawn" we buy for our mushroom beds. 

 A small bit of it transferred to a break in the bark of a healthy 

 chestnut tree will produce the chestnut bark disease. Rains wash 

 the disease down the trunk of an infected tree but woodpeckers, 

 squirrels, and insects are the chief means of carrying the disease 

 from one tree to another. 



Following a question which Dr. Metcalf answered regarding 

 the difficulty of detecting the disease, Mr. Curtis stated that 

 there are bulletins published by Dr. Metcalf and also recently 

 by Prof. Rane, the State Forester, containing excellent photographs 

 of various stages of the disease. These can be had for the asking 

 and are a great help in detecting the disease. 



The question was asked, " How is Mr. Curtis fighting the disease 

 in the Arboretum? 



Mr. Curtis replied, "The first thing is to become familiar with 

 the disease. Our first case was discovered in December, 1909. 

 I do not say that this was the first authentic case in Massachusetts 

 but it was the first case in this part of the State. Fortunately 

 this was only a few days before the Boston Meeting of the American 

 Association for the Advancement of Science. Dr. Metcalf was 

 present at this meeting and took some of our material for examina- 

 tion. As soon as the disease was definitely determined, we notified 

 Prof. Rane, the State Forester, Mr. Pettigrew, the Boston Park 

 Superintendent, the several Metropolitan Park Superintendents, 

 and all others whom we thought might be interested in the disease. 



