one of the most serious problems with some
selections of the Chinese chestnut is the spoilage of the nuts. Marvin
E. Fowler made a study of this trouble at Savannah, Ga., and found that
most of the trouble in that restricted area was caused by a
Gleoesporium-like fungus that infects the nuts at the tip.[10] Because
spraying experiments did not give control, the more susceptible trees
have been removed. In most parts of the South, however, this fungus is
not the primary cause of nut spoilage and the limited work so far
carried out has not revealed the cause. Part of the trouble may be due
to physiological break-down. As individual trees vary greatly in
susceptibility to this deterioration of the nuts, orchardists are
advised to top work or eliminate the more susceptible trees. Some people
have believed that exposure of the nuts to the hot sun while in the bur
or on the ground may cause damage. The market for Chinese chestnuts can
be ruined by shipping nuts that are partly spoiled by the time they
reach the consumer.

[Footnote 10: Gravatt, G. F., and Marvin E. Fowler. Diseases of chestnut
trees and nuts. Northern Nut Growers Assoc. Rept. (1940) 31: 110-113.
1941.]

+Phytophthora Root Disease of Chestnut+

Phytophthora root disease, caused by _Phytophthora cinnamomi_, is
treated briefly here, and interested nut growers can consult the
detailed earlier article.[11] Briefly, this fungus is considered as
introduced into this country over a hundred years ago. It killed the
chestnut and chinkapin growth over large areas in the southern States.
Asiatic chestnuts are highly resistant to this disease, and when grown
on well-drained soils have not been damaged. Our test plantings of
Chinese chestnuts growing in the same soils where susceptible trees of
American and European chestnuts were killed, continue to make a vigorous
growth. The European and American chestnuts and their hybrids growing in
the western States are in danger from this fungus as it has now been
reported in the West. This same fungus sometimes kills thousands of
young nursery trees of the black walnut, but these epidemics are usually
brought on by unusual weather conditions. Poor soil aeration, induced by
excessive rainfall and poor drainage, makes ideal conditions for damage
to the walnut and other hosts by _Phytophthora_. Even the very resistant
Chinese chestnut roots are invaded by the fungus when the soil remains
waterlogged for extended periods.

+B