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 inter stitialis (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 ru.le, however, the canes and roots, although often 



