ustration: Fig. 1.]

Whenever chestnut trees are attacked by the blight fungus, suckers arise
below the lesion, and if the lesion is at or near the base of the tree,
as often happens, these suckers grow from the base of the tree, i.e. at
the root collar. It is then a simple matter to cut out the diseased bark
of the lesion with a sharp knife, paint over the wound, and graft the
tip of one or more of these suckers _above_ the lesion, into the healthy
bark. Of course the sucker must be long enough to reach the healthy part
of the bark above the lesion. It is measured roughly by the eye and then
cut off at a proper length, usually a little longer than seems
necessary. The tip is then sharpened into two beveled surfaces coming up
to a thin sharp transverse edge like a long wedge. (Fig. 1a.) The tip
edge must be very sharp in order to push up easily between the bark and
wood. Now, or rather, before trimming the sucker, in the healthy bark
above the blight lesion cut an inverted T, making the cut into the bark
as far as the wood and then cut a gradual slope from the surface of the
bark down to the horizontal part of the inverted T. Next, lift the bark
gently from the wood above the horizontal cut and insert the end of the
sucker. If the sucker, or scion, is slightly longer than the upper end
of the cut, it can be bent outward at the same time that the scion is
being inserted and thus a spring is secured making it easier to force
the scion up between bark and wood. I should add that if the lesion is
not at the base of the tree, suckers usually arise just below it in any
case, and these can be inarched in the same way as the basal shoots.

[Illustration: Fig. 2

Fig. 2 Showing inarching method of controlling the chestnut blight a
Chinese-Japanese hybrid chestnut, 13 yrs. old, infected toward base with
Chinese type of blight, i.e. in outer bark only. Right: sucker inarched
in spring of 1946; left, inarched spring of 1950. (The black figure
resembling an arrow, about half way up, is accidental, being a cluster
of labels.) b. Grafted tree (the large tree of Japanese-American
chestnut on Japanese stock); graft made in 1937 where finger is
pointing; left: inarch of 1947, itself inarched near base in 1950;
right, inarch of 1949. c. Japanese-American hybrid chestnut with
principal inarch made in 1943; other later inarchings showing in part.
All photos by Louis Buhle, Brooklyn Botanic Garden, and loaned courtesy
of the Garden.]

Th