Plant Diseases of 1901 . 
9 
an abundance is promised the Mesa for the coming season, it is not 
likely that this disease will be very injurious on soils that are of suf¬ 
ficient depth to make suitable orchard land. 
APPLE INJURY FROM SPRAYING WITH BORDEAUX 
MIXTURE. 
Complaints were received from correspondents at Canon City 
and Montrose that spraying with Bordeaux mixture had seriously 
injured the fruit of certain varieties of apple trees. The injury pro¬ 
duced is well shown in the illustration in Plate VIII., Fig. 3, which is 
from a photograph of a Ben Davis apple that is so disfigured as to be 
unsalable. This variety appears to be very susceptible to such 
injury, though a number of other kinds were injured more or less. 
All degree of disfigurement occurred, from a slight russeting of the 
skin to the malformation shown in the figure. 
That the corrosive action of Bordeaux mixture is responsible for 
this condition there can be no doubt. The subject has attracted con¬ 
siderable attention in the Eastern States, where it has been found 
that such injuries are much more common in some seasons than in 
others. Just what the conditions are that favor this action of the 
mixture have not been determined and the subject is still in an 
experimental stage. This is particularly true of the arid regions, 
since fungicides are just beginning to be used here on fruit trees. 
In the light of our present knowledge, it can only be recom¬ 
mended that great care be taken to see that the mixture is properly 
made. The formula on a subsequent page has been found to be suf¬ 
ficiently strong for combating fruit-tree diseases as they occur in other 
States. Further experience with spraying in Colorado may show 
the necessity of modifying the formula to suit our conditions. And, 
finally, Bordeaux mixture should not be used unless it is needed. 
In the vicinity of Canon City it is said that the bitter rot of apples 
is abundant and the orchardists sprayed their trees with the mixture 
for the purpose of combating this disease. But in the majority of 
the fruit growing districts apple trees are not yet affected to any 
extent by such plant diseases as can be controlled with Bordeaux 
mixture. 
BLACKBERRY ROOT DISEASE. 
( Rhizoctonia . Sp.) 
% 
There was a noticeable amount-of light green or yellowish foli¬ 
age on the blackberry and raspberry plants in the College plantation 
last spring, which did not regain its normal color. Later in the 
season leaves on occasional plants began to curl and shrivel as 
though suffering for moisture, and some of the plants died. Appar- 
