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Spur Blight 

 Caused by Mycosphacrclla ruhina (Pk.) Jacz. 



Spur blight, or "gray bark," is a disease of the red raspberry. It 

 appears on young canes as a brownish discoloration, located usually just 

 below the leaf stems on the lower parts of the canes. It can be seen 

 after about the middle of July. The diseased area then enlarges length- 

 wise of the stem for several inches above and below the nodes, and the 

 bark becomes dry and brown, and splits longitudinally. Later, usually 

 in September, tiny black spots appear on the diseased areas. 



The damage done by this disease is of the same nature as that done 

 by anthracnose and cane blight. Spur blight is, however, so uncommon 

 that the actual loss in the state is slight. 



The present known occurrence of spur blight in Illinois is shown on 

 Map 86. It has been found in six counties only, all of which are in north- 

 ern Illinois. 



Control is not usually necessary, but where desirable may be attained 

 by the application on young canes only of 3-2-50 Bordeaux mixture to 

 which has been added two pounds of rosin-fish-oil soap. Four applica- 

 tions should be made, at two-week intervals, beginning when the canes 

 are 8 to 12 inches high. 



Leaf Spot 



Caused by Mycosphacrclla rubi Roark 



Leaf spot, also known as Septoria leaf-spot, is the most common 

 of the bramble diseases. Red raspberry and dewberry are most suscep- 

 tible to it but it is unusually abundant on all the brambles. It begins to 

 appear early in June as small purplish spots on the leaves. These enlarge 

 somewhat, their centers turn gray or ash-color — on the blackberry tan 

 or brown — with a definite purple border. Eventually minute black dots 

 appear scattered over the spots. 



Injury from this disease is usually limited to the leaves, but canes 

 may sometimes be diseased. In favorable seasons infection may become 

 so severe as to cause early and damaging defoliation. 



The earliest record of this disease is a report of its occurrence in 

 Illinois in 1887 by G. Martin^ under the name of Rhabdospora. No 

 specific locality is given. Under the name of Septoria rubi West., it was 

 reported by l'>urrill in Champaign county in 1911 and in Champaign and 

 Union counties in 1912. 



It is now known to occur in Illinois as indicated on Map 87. It has 

 been found in 35 counties widely distributed over the state. Its distri- 

 bution is not uniform, however, and occurrence is rare northward. It 

 increases in frequency southward, until in the southern third of the state 

 it appears to be abundant everywhere. 



'Journ. Myc. 3: 90. 1887. 



