good crops of nuts.
Later, the Calhoun variety was grafted on some lower limbs, and has
remained healthy. The diseased Allen grafts are still in the tree, are
now 15 years old, and are more or less alive, but in very poor
condition, with the signs as found in what I call the latent form. In
1938, the McDermid Persian walnut was grafted into this same tree, and
its grafts produced good crops of nuts.
I wish to cite another instance of how little the Persian walnut is
affected, regardless of variety. In 1938 a large black walnut near the
house was grafted with Persian grafts, on stubs that had failed the
previous year. The tree had the second, or rapid growing form, of
brooming disease. I have pictures showing how badly the 1938 grafts took
the rapid growing form of growth; while two 1937 Persian grafts showed
no signs of trouble. The tree started to bear in 1941, and has made
remarkable growth. It is now one of the nicest Persian walnut trees I
have, bearing heavily every year. It is about 30 feet tall and 20 feet
broad, with no apparent signs that it was ever affected.
I feel we should recognize the fact that eradication of brooming disease
is impossible; but one should plant, or graft, those varieties known to
bear good crops in spite of this trouble. The Thomas and Grundy black
walnuts do very well here, as well as the two local nuts mentioned. I do
not know of any Persian varieties affected. I do not have any Persian
trees with the typical broomy bunch, as is so often seen in the Japanese
walnut, and its hybrids. The native black walnuts, when affected, seem
to fail to fill properly, are immature, and watery, black veined, and
worthless at harvest time, shriveling to a dark, hard, kernel when
cured.
I think this answers the oft-asked question, "Why do not my black
walnuts fill as they used to?" There is a strange relation to the
filling of the native black walnut and the days of 1934 and 1935, when
we had the great walnut caterpillar scourge!--when the trees were
stripped of all their leaves. Ever since, we have had the brooming
disease to contend with. One could jump to the conclusion that improper
filling and this trouble were caused by a lack of certain nutrients; but
seedlings in nursery rows are often affected, even where they are given
every care.
At one time this spring I thought I had found a new way of
"bench-grafting" walnuts. Seven grafts, on black root, were made in
December, and were planted di
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