232 



It is difficult to control, and measures must be thoroughly and con- 

 scientiously carried out if the desired results are to be obtained. Lime- 

 sulfur is applied as a spray before growth starts (25/2 gallons lime-sulfur 

 to 50 gallons water) and again just before blossoming. New plants 

 should be free from anthracnose when set. In the patch clean cultiva- 

 tion is essential, as the shade and moisture provided by rank weeds are 

 extremely favorable to infection. 



Cane Blight 

 Caused by Leptosphaeria coniothyrium Sacc. 



Cane blight is known only on the raspberry. Both red and black 

 varieties are subject to attack. This, like anthracnose, is primarily a 

 disease of the canes. The first sign of its presence is a wilting of 

 branches about the time the berries start to ripen. On the canes, below 

 the wilted branches, there may be found at this time diseased areas usual- 

 ly several inches long in which the bark is light-colored and the wood 

 dead and discolored. On diseased bark there appear small black dots, 

 which are often surrounded by smoky halos. 



Damage from this disease results first from its direct effect upon 

 the fruit of wilted branches and second from its injurious effects upon 

 the plant itself. The crop loss from it in Illinois is estimated at about 

 0.5 per cent annually. 



The earliest report we have of cane blight in Illinois is one by Bur- 

 rill, mentioning its occurrence during 1912 in Kane and Randolph coun- 

 ties. These two occurrences, one in the extreme north and one in the 

 extreme south of the state, indicate that at that time it may have been 

 much more widely distributed over the state than was supposed. 



Its present known occurrence in the state is shown on Map So. It 

 has been found in 36 counties, and has a wide though irregular distribu- 

 tion, reaching both the southern and the northern borders of the state. 

 Southward, its occurrence is only occasional, as shown by the few coun- 

 ties in which it has been found, and the limited number of times it has 

 been seen. The northern third of the state appears to be an area of con- 

 centrated occurrence, from which more than 60 per cent of our speci- 

 mens and reports have come. 



Control of cane blight can be attained in some measure through the 

 use of resistant varieties. The Columbian is reported to be very resist- 

 ant, and the Cuthbert most susceptible. Sprays applied for other dis- 

 eases are helpful but do not prove satisfactory alone. The nature of 

 the disease and its life history suggest that new plants should be free 

 from it when set, that old canes should be cut out and burned as soon 

 as possible, and that care should be taken in cultivation to avoid injuring 

 canes and thus providing points of entrance for the fungus. 



