CHESTNUT BLIGHT IN MICHIGAN 17 
The majority of the older orchards and experimental plots in the United 
States, which contain the Chinese chestnut Castanea mollissima and the 
Japanese chestnut Castanea crenata are located in the East. Comparatively 
little can be said at this time regarding their suitability for planting in 
Michigan. The chestnut blight organism has been able to attack these trees 
in orchards in this country but, without doubt, many of these chestnuts 
exhibit considerable resistance. Undoubtedly, individual specimens of these 
foreign trees may attain large size in the Orient but the trees already planted 
in orchards in this country seem to indicate that this foreign stock generally 
exhibits a small spreading form and rarely grows over forty feet in 
height. The flavor of the Chinese chestnuts is said to be superior to the 
Japanese or European species. However, due to the dwarf nature of these 
trees, it is doubtful if they will ever be of value in forest planting work. 
Control and Recommendations 
All efforts to control the chestnut blight in the American forests, as well 
as in orchards where the stock is native, have failed. Many such practices 
have simply served to prolong the life of the affected trees. It is believed 
that native chestnut will largely disappear from the State. 
Although direct control is impracticable, hope has been expressed by many 
chestnut owners regarding the development of immunity to the blight by 
the native trees. Little evidence is to be had at present which supports this 
view. It seems that the immediate development of the native chestnut 
to a relatively high degree of resistance to this disease is very remote. 
A number of varieties and species of chestnut from China and Japan 
which have been planted in this country show different degrees of blight 
resistance. The Office of Forest Pathology, United States Department of 
Agriculture, has been making an extensive study of chestnut blight in Asiatic 
stock. This office has found that some of the trees are highly resistant and 
that the blight can be controlled by constantly pruning out the infections in 
the infected trees. 
Although it is not likely that such foreign stock will ever be planted 
extensively as forest trees under the present economic conditions, and be- 
cause of the dwarfed habits of the majority of these foreign trees, Asiatic 
stock may offer a solution of the problem for the orchardist. The nuts are 
inferior in quality to those of the American tree but it seems reasonable to 
expect the results from hybridization experiments to yield a highly resistant 
tree which produces nuts equal in flavor and size -to the Paragon and 
native chestnut tree. 
It is evident that native chestnut trees should not be planted in Michigan 
orchards and forest plantations. In orchards already established, a careful 
and frequent examination should be made of the trees. Slight infections 
should be pruned out arid burned in the effort to prolong the life of the 
tree. Although it is useless to try to save badly infected trees, such trees in 
the orchard are sources of infection and should be burned promptly. 
