damage to the susceptible oaks in Spain, Portugal, and the western 
half of France maybe very materially hastened. 
49. Chestnut blight can be kept under control in small isolated 
orchards of European chestnut under conditions such as exist in 
the central part of California, U.S.A. There is an extensive 
European chestnut orchard established there, and in 1934 the blight 
was found in several of the orchards. Immediate steps were taken 
for inspection and eradication of the infected trees, and though the 
blight still continues to appear there each year on a limited num- 
ber of trees, it has been kept under control. It is difficult to find 
all of the new infections before they have time to produce spores 
and cause additional infections. The chestnut orchards in Califor- 
nia are growing in an area of low rainfall and are mostly irrigated, 
producing heavy yields of nuts. 
50. The chestnut blight infections in the states of Oregon and 
Washington were eradicated and no additional infections have been 
reported in these two States in recent years. These trees were 
growing in areas with heavier rainfall under quite different climatic 
conditions from those in California where European chestnuts are 
growing. A number of advance spot infections of the chestnut blight 
were successfully eradicated in native American chestnut growth 
in eastern United States but very thorough and careful work is 
required to eradicate and control such infections. 
51. From experience with conditions in the United States, it is 
thought that small spot infections which appear long distances 
ahead of the main areas of spread of the disease can be success- 
fully eradicated or kept under control.It is also possible to cut out 
and treat individual infections on the trunks of the trees and in this 
way save the trees. 
52. Extensive studies on the spread of the chestnut blight into 
new territory have shown that, spot infections occur long distances 
ahead of the main infection sometimes as much as 100 to 500 miles. 
The disease spreads around these spots in all directions. It may 
be 10 to 20 years before the main heavy infections of blight the 
blight has advanced into the territory where the spot infections 
have been steadily enlarging. We know that by eradicating these 
early spot infections progress of the disease over a watershed, 
valley, or other area can be greatly delayed, even though ultimately 
the blight is going to sweep over such areas. 
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