16 THE JOURNAL 
to quarantine against the bark disease 
on chestnut nursery stock, and they 
should now take special care that no 
shipment, however small, escapes their 
rigid inspection. 
A PRACTICAL DIFFICULTY. 
The most serious practical difficulty 
in inspecting nursery stock for this, as 
for other fungous diseases, lies in the 
fact that virtually all State inspectors 
are entomologists and are usually not 
trained in recognizing the more obscure 
symptoms of fungous disease. Nursery 
trees affected by the bark disease rarely 
show it prominently at the time when 
they are shipped; the threads of conidia 
or the yellow or orange pustules are 
rarely present, and usually all the in- 
spector can find is a small, slightly 
depressed, dark-colored area of dead 
bark, usually near the ground, which is 
easily overlooked or mistaken for some 
insignificant injury. Upon cutting into 
such a spot the inner bark shows 
a most characteristic, disorganized, 
“pounky”’ appearance and characteristic 
“fans” of the yellow mycelium of the 
fungus. Occasionally a very characteris- 
tic yellowish brown or reddish band or 
blotch, either girdling or partly girdling 
the young tree, may be seen. 
If infected trees are set out they 
develop the disease with its characteris- 
tic symptoms the following spring. On 
account of their small size such trees are 
girdled and die before the end of the 
summer. Meanwhile they become a 
source of danger to neighboring orchard 
and forest trees. Orchardists and nur- 
serymen purchasing chestnut trees are 
therefore urged to watch them closely 
during the first season, no matter how 
rigidly they may have been inspected. 
In view of the uncertain future of the 
chestnut tree the planting of chestnuts 
anywhere east of Indiana, at least for 
the present, can hardly be advised. 
West of the natural range of the Ameri- 
can chestnut, however, the situation is 
quite different. Obviously the western 
chestnut orchardist has before him a 
great opportunity. No matter how 
successful efforts to limit -the bark 
disease may be, the nut crop will be 
reduced for some years, and the business 
oF HEREDITY 
of growing fine orchard chestnuts in 
the East will be depressed for the same 
length of time. There is no apparent 
reason why, with rigid inspection of 
purchased stock and of the orchards 
themselves, ali chestnut orchards and 
nurseries from Indiana to the Pacific 
coast can not be kept permanently free 
from the bark disease; therefore, all 
persons interested in growing the chest- 
nut in the West are earnestly advised to 
be sure that stock from any source is 
rigidly inspected, to watch continually 
and with the utmost care their own 
nurseries and orchards, and to destroy 
immediately by fire any trees that may 
be found diseased. The discovery of 
an infected orchard in British Columbia 
indicates that other chestnut orchards 
will probably be found on the Pacific 
coast which have become infected by 
direct importation from the Orient. 
BREEDING NECESSARY. 
Probably the most practical control 
resultsin the long run will be obtained by 
the breeding and propagation of varieties 
of chestnut that are immune or highly 
resistant to the bark disease. Else- 
where in this magazine Dr. W. Van 
Fleet has described his work in this 
line. It appears that so far no immune 
or even resistant individuals of the 
American chestnut have been found, in 
spite of strenuous search; so that we 
must largely depend on the Asiatic 
varieties. The slight resistance of the 
chinquapin, as observed in. the field, 
may be due only to its comparative 
freedom from bark insects. The species 
of Chinese chestnut upon which the 
disease occurs in China (fig. 1) is ap- 
parently resistant to the disease in 
that climate, but it remains to be seen 
to what extent this resistance will 
persist when the trees are grown in 
America. The Japanese chestnut is 
highly resistant, and certain strains 
apparently immune; these strains form 
at present the most hopeful basis for 
breeding. At present we do not know 
exactly what the Japanese chestnut is; 
most of the trees that pass under this 
name in the American market appear to 
be hybrids with the American or other 
varieties. 
