Plant Diseases of 1901. 
17 
as the experiments indicate that the disease is most destructive when 
the plants are small. 
Third—As little water should be used in irrigating as can be 
gotten along with, since root fungi in general thrive best in a wet 
soil. 
Fourth—It is within the range of possibilities to secure a va¬ 
riety, or strain of some variety, of peas that will resist the attacks of 
this fungus. Recent reported advances made in plant breeding en¬ 
courages us to believe that such a strain may be secured, and we 
hope to undertake work of this nature the coming season. 
PLUM LEAF BLIGHT, OR SHOT-HOLE FUNGUS. 
A common disease of plum and cherry trees, known as leaf 
blight or shot-hole fungus, is illustrated in Plate IX., Fig. 1. A 
common effect of the fungus is to destroy small areas of leaf tissue, 
which drop out and leave circular holes, thus suggesting the name. 
When many of these holes run together the greater part of the leaf 
is destroyed. If the fungus is severe in its attack and the leaf sur¬ 
face is materially reduced during the active growing season great 
injury is done to the trees. 
Numerous experiments have proven that this leaf blight may 
be easily controlled by spraying with Bordeaux mixture. *Beach 
recommends that three sprayings be made as follows: The first 
about ten days after the blossoms have fallen; the second about 
three weeks after the first, and the third about four weeks after the 
second. 
This disease is reported as being quite abundant in some sea¬ 
sons in sections of Colorado. In such localities it will undoubtedly 
pay to give the treatment recommended a trial. 
POTATO DISEASES. 
Potato diseases are being made the subject of special investiga¬ 
tion at this Station, as mentioned on another page, and a report of prog¬ 
ress of the work is soon to be published in bulletin form. Whether 
the fungus that has been found to be so destructive to this crop can 
be entirely overcome has not been determined, but much good can 
be done by treating seed potatoes. 
It is our purpose merely to call attention to the subject at this 
time, and for the sake of convenience, formulas for disinfecting seed 
potatoes are given on the following page. 
♦Beach, S. A. Rep. N. Y. State Exp. Sta. 1896, p. 399. 
