70 
Diseases at the Hamden Plantation.—As has often been declared 
by plant pathologists, winter injury (in the strictest sense, itself a 
disease) 1s the worst of all tree diseases. For, by killing or weak- 
ening some of the plant tissue, it furnishes the start or foothold 
for many a destructive disease induced by parasites. The truth of 
this statement 1s borne out by the situation at our plantation. The 
very severe winters of 1933-4 and 1934-5 killed outright or in 
part many of our trees. When only a part of the tree was killed, 
a way was left open for the entrance of the chestnut blight fungus 
for other fungi.* “The Spanish chestnuts were particularly 
or 
affected by the cold, most of the Japanese forest type were con- 
siderably set back, and we find now that some of the highly cher- 
ished Chinese, that we thought extremely hardy, suffered from 
winter injury at the bases and consequently were attacked last 
year at these points by the blight. The Americans, however, evi- 
dently since they are descendants of a race which has been ac- 
customed to such cold spells for many millions of years, proved to 
be extremely hardy, showing not the slightest sign of winter 
injury. The same is true of the Japanese-American hybrids, 
which apparently inherit (in most of our specimens, at least) the 
hardiness of the American parent. 
Bhight—In a few cases Japanese-American hybrids were 
alfected with the blight. This is, of course, to be expected, since, 
naturally, some of the crosses would inherit the susceptibility of 
the American parent. As we said in a former report, we are not 
trying to keep the blight away from any of our trees. Whether 
or not an individual is susceptible, is one of the facts we are striv- 
ing to obtain. It is fortunate, therefore, that in the woods sur- 
rounding the plantation (formerly the home of many fine native 
chestnuts) there are many diseased chestnut shoots, so that the air 
l supplied with /:ndothia spores. 
— 
of the plantation must be we 
Thus the plantation is continually subjected to what may be 
termed a “ passive” test. Later it may be advisable to subject 
active ’’ quantitative test, i.e. by means of inocula- 
is 
each tree to an 
tion of the living bark with the fungus. 
* It must not be inferred that chestnut blight dev ea only as a result of 
winter injury: the fungus may enter through any dying or dead tissue, or 
any wound in the bark caused in any way ee 
