162 MANUAL OF FRUIT DISEASES 
adhesive, and the soap will aid in the control of leaf-hoppers. 
(2) Spray two or three weeks after the petals fall, using bur- 
gundy mixture in place of bordeaux. This substitution is 
made in order that no precipitate will be apparent after the 
fungicide has dried on the berries; for coating the berries with 
a spray that shows at picking-time is objectionable. The 
burgundy mixture is made from the following formula: copper 
sulfate (blue vitriol) two pounds, sal soda (washing soda) three 
pounds, and water one hundred gallons. To this mixture is 
added one pound of soap to each fifty gallons. The soap should 
be dissolved and added to the mixture after the spray tank is 
filled. The mixture should be thoroughly agitated during the 
spraying operation. 
Under Washington conditions, profit from this measure of 
control is obtained through increased quality and quantity of 
healthy berries, and by the prevention of cane girdling. The 
practices of cane removal and spraying in the fall have been 
found to be unnecessary. 
(This disease is more fully discussed under Raspberry, page 
406.) 
REFERENCE 
Rees, H. L. Experimental spraying for blackberry anthracnose. 
Washington Agr. Exp. Sta. Monthly bul. 3:8:2-10. 1915. 
OranGE-Rust 
Caused by Gymnoconia interstitialis (Schlecht.) Lagerh. 
The leaves of blackberry are commonly affected with orange- 
rust. The disease appears in the early spring as large, bright, 
orange-colored patches on the lower surface. The affected 
leaves are dwarfed and rolled slightly, exposing their rusted 
lower surfaces. Sometimes the rust patches are found on the 
canes. As a rule, however, the canes and roots, although often 
