34 



moil innni, down the trunk, and around the trunk. >Vlieu 

 these portions of the disease Avhioh go around the trunk meet on 

 the other side, we have a branch or a trunk Avliich we speak of as 

 girdled. Now a girdled branch, or a girdled twig, or a girdled 

 trunk, means the early death of all parts of the tree beyond the 

 girdled area. If it is a twig, it means the death of the twig be- 

 yond the girdled area. If it is the trunk, it means the death of 

 the whole tree at once, or soon after the girdling is completed; 

 not immediately, as a rule. Now I want to call your attention to 

 some of the obvious effects of this girdling upon the foliage of 

 the tree. When you are looking for this disease during the sea- 

 son of foliage, it can be detected oftentimes at a great distance. 

 I have myself detected diseased trees more than a mile away, or 

 trees supposed to be diseased, by the characteristics which I wiint 

 to call your attention to now. To be sure, you must bear in mind 

 that the coloration of the leaves to which I am going to call your 

 attention can at times be brought about by other things than this 

 disease; but Ave have in the coloration of the leaves, as Ave gener- 

 ally say, the "danger signal" which suggests Avhere to look for the 

 disease; for, if the disease has been going on very long, for a fcAv 

 months, or Aveeks even, in certain places, Ave shall get some of 

 these discolored leaves as the result of the girdling of some one 

 or more of the tAvigs or branches. I have shoAvn here a someAvhat 

 normal chestnut leaf. It is a little broader than the normal leaf; 

 this is intended to represent not, perhaps, a perfectly typical 

 chestnut leaf, because we have on the margin a little paler green 

 than in the portion in the centre. The pale green in the margin 

 of every leaf at times, is one of the first symptoms of discolora- 

 tion. It becomes a little pale. First of all, perhaps, the leaf 

 wilts a little, if you notice it carefully, and if this paleness of the 

 leaves is extended over the leaves of a whole branch, the effect as 

 a Avhole is quite noticeable. 



No. 16. Here is a greenhouse plant Avliich has been inoculated 

 with the disease. At the left Ave find some of the normal chest- 

 nut leaves; at the right a branch Avhich had been inoculated and 

 has been girdled Avay doAvn here. (Indicating). Now I do not 

 know about that particular specimen, but, if we Avere looking for 

 the disease on such a specimen as that, we should never look ui) 

 here for it, that is, not primarily. What is causing the trouble 



