CONTROL OF THE CHESTNUT BARK DISEASE. 19 
the edges of the cut-out areas. Except in the early spring this is 
not difficult after a little experience in manipulating the gouge and 
mallet, provided the gouge is kept sharp. 
Small branches which have become infected should be cut off, the 
cut being made well back of the disease—at least 2 or 3 inches, if 
possible. 
All cut-out areas and all the cut ends of stubs should be carefully 
and completely painted with coal tar. A good grade of paint has 
been recommended by some authorities as superior to tar, but it is 
more expensive. If the tar is very thick, the addition of a little creo- 
sote will improve it for antiseptic purposes as well as for ease in 
applying. If the first coat is thin, a second one of fairly thick tar 
should be applied within a few weeks or months. Other coats should 
be applied later whenever it becomes necessary. 
The entire tree should be carefully examined for diseased spots and 
every one thoroughly cut out and treated in the way already de- 
scribed. In case of suspicious looking spots a portion of the outer 
bark can be cut out with the sharp gouge as a test. If this cut shows 
the characteristically discolored bark the spot can be considered as 
diseased and cut out accordingly; if the cut shows healthy bark, it 
need merely be treated with tar or paint, as other cuts are treated. 
In examining a tree for diseased spots it is always best to begin at 
the base of the trunk and work up, for if the trunk is girdled at the 
base it is useless to work anywhere on the tree. 
When the spores of the fungus are present, especially in the form 
of threads, or “horns,” they are readily washed down the branches 
and trunk by every rain, and are thus carried down to or toward 
the base of the tree. As a result the base of a tree, the crotches, and 
other places which afford easy lodgment for the spores are particu- 
larly subject to infection. 
Although spraying with any of the standard fungicides appears 
to have no effect whatever in stopping the progress of the disease 
after it has once started in the inner or middle bark, there is little 
doubt that it is of use in preventing infection from spores washed 
down by rain from the upper part of a tree or from spores which 
have been transported from other trees. For this reason the spray- 
ing, after each rain, of the parts of a tree below a spore-bearing 
lesion is recommended, but only on an experimental basis. If no 
spore-bearing lesions occur on the tree, there is less apparent reason 
for spraying. The scattering of slaked lime about the base of a tree 
and the whitewashing of the trunk and larger limbs have shown 
apparently beneficial results in preventing infections and perhaps 
also depredations of borers. 
A tree which is being treated for individual infections must be 
carefully watched and the diseased spots promptly cut. out as they 
appear. For this purpose each tree should be examined very care- 
fully two or three times at least during the growing season. 
467 
