492 INSECTS AFFECTING VEGETATION 



above the injury suddenly wilt and die. By the time this happens, 

 the cane at the point of attack is dead throughout a section which is 

 usually from two to four inches in length. Both above and below 

 this dead section of the cane itself may be normal, with nothing to in- 

 dicate the cause of the sudden wilting of the leaves. However, a 

 cane may bear several of these dead sections of various sizes. If the 

 point of attack is near the ground the whole cane dies ; if higher up, 

 only a part of it. When part of a cane dies while the remainder con- 

 tinues alive, the point of attack is to be sought at the boundary be- 

 tween the dead and living portions. Usually, the seat of the difficulty 

 may be located by the color of the bark, which is somewhat different 

 from that on the rest of the cane. For the most part it is lighter 

 colored and smutty, with smoke-colored patches of exuded spores. 

 In many cases numerous minute pimples, the pycnidia of the 

 fungus, are visible. By cutting into the cane with a knife the 

 matter may be decided at once. Where the cane is diseased the wood 

 is strongly discolored. A marked characteristic of cane blight is the 

 brittleness of the cane at the point of attack. 



While it is common, both with black caps and red varieties, for 

 the disease to be confined to one or more definite areas of infection on 

 the cane there are also many instances in which the disease pervades 

 a large portion of the cane before death occurs. In such cases it is 

 common for the affected wood to crack and the bark to peel off, par- 

 ticularly on the lower portion of the cane. 



Fruiting canes affected with cane blight may die at any time. 

 Almost as soon as the leaves unfold in the spring branches commence 

 to die. As the season advances the disease increases in virulence and 

 reaches the maximum during the ripening of the fruit. Canes loaded 

 with ripening fruit suddenly wilt, either wholly or in part, and dry 

 up. The disease does not spread from an initial center, but canes 

 die here and there all through the plantation. Thrifty, well-cared- 

 for plantations suffer as well as neglected ones. 



So far as observed, only the canes are affected. The disease 

 certainly does not attack the leaves, and the fact that new canes in 

 badly diseased plantations make as good a growth as those in healthy 

 plantations, indicates that the roots are not affected. 



In August and September the new canes of red raspberries often 

 show bluish-black or brown areas from two to four inches in length 

 and extending nearly or quite around the cane. These discolored 

 areas are very conspicuous and at one time were mistaken for the 

 early stage of cane blight. Probably they have nothing to do with 

 cane blight. (K Y. [Geneva] E. S. B. 226.) 



Raspberry Yellows. The Marlboro red raspberry, a once 

 popular variety, is said by fruit growers to be running out. In 

 Ulster County particularly its culture is said to be no longer profit- 

 able; and throughout the Hudson Valley one frequently hears of 

 the ravages of the Marlboro disease. The foliage and fruit dry 

 up sometimes gradually, sometimes suddenly. There has been 

 much speculation concerning the cause of the trouble. 



