32 
Colorado Experiment Station 
over-irrigation, and crowded condition of plants favor its develop¬ 
ment. 
Control .— (i) Bordeaux mixture readily controls it. It is sel¬ 
dom a practical remedy, however, as the disease is not often severe 
enough to warrant the expense. 
(2) Keep soil well-drained. 
(3) Do not overcrowd the plants. 
(4) Early crops are not as liable to attacks of fungus as late 
crops. 
PEACH. 
Scab.— The disease is found on fruit, leaves, and twigs. It is 
also known as “black spot” and “freckles.” Spots on the fruit are 
about of an inch or less in diameter, dark brown to blackish, and 
nearly circular. Diseased areas are found only on the surface and 
may be slightly depressed when many spots come together. Fre¬ 
quently, individual spots crack. If a mass of spots come together, 
producing a “smutty” or blackish appearance, the peach cracks open 
and shrivels. Infection is most abundant about the stem attachment 
and weather side of fruit. On the leaf the spots are nearly circular 
and are formed only on the surface. They are pale green in early 
stages and a yellow-brown or purple in later stages. Wood of the 
current season may be attacked. 
Control .— (i) The disease is very easily controlled by spray¬ 
ing. Spray with 8-8-50, self-boiled lime-sulfur, about one month 
after the petals drop and again three or four weeks later. 
Blight. —This disease occurs on fruit, leaves, and stem. The 
spots on fruit are irregularly oval to circular. At first, they are 
pink, but later become typically brown with a pink outer ring. 
These spots are slightly raised and found only on the surface 
Gumming is not abundant on diseased fruit. Badly infected fruit is 
shed early. On leaves the spots are irregularly circular and reddish 
to brown in color. Spots may fall out, causing shot-holing. In 
severe attacks, defoliation may take place. On twigs the spots are 
irregularly oval in shape. At first they are reddish, but later become 
brown to black, and often sunken. Gumming is generally conspicu¬ 
ous on diseased twigs. Buds on the fruiting wood are killed. 
Control .—Spray in the fall with Bordeaux mixture, 4-5-50 
formula. 
Powdery Mildew. —The leaves, twigs, and fruit are attacked. 
White irregular blotches are produced on the leaves, mostly along 
the midrib. In the shade, both leaf surfaces are affected. JThe 
leaves crinkle, curl, and in severe cases the younger ones near the 
tip fall. White blotches are formed on diseased twigs (Plate IX). 
