SMALL FRUITS ^s 



BLACKBERRY, DEWBERRY, RASPBERRY 



The disease of these three crops, of the genus Rubus, are 

 so nearly identical that they may be treated under one 

 caption. 



Anthracnose 'i^-i^o, 150 [Plectodiscella veneta Burk., GIobo- 

 sporium) . — The anthracnose, on both blackberries and 

 raspberries, is one of the most serious and widely distributed 

 diseases of these crops. The first publication in America 

 regarding it seems to have been made in 1882 by Burrill. 

 Since then numerous papers from many sections attest its 

 importance. In 1907 it was estimated to have injured one- 

 third of the crop in Nebraska, one-half in Wisconsin, and 

 even more in Illinois. The chief seat of attack is the cane, 

 especially upon young stalks, though the disease appears 

 also upon both petioles and leaves. 



The fungus often appears upon young canes before they 

 are 25 cm. high, making small, purplish spots, which soon 

 become grayish or dirty white in the centers. The borders of 

 the spots are purplish and slightly raised. Later as the spots 

 enlarge they coalesce, making irregular blotches 2 cm. or 

 more long, which often encircle the cane. The stalk then 

 withers and dies from lack of sap supply. Badly diseased 

 canes present a bark of rough, scabby appearance due to the 

 efforts of the cane to heal the wound. Canes occasionally 

 crack from this disease. The chief injury is to the cambium 

 layer or the sappy outer wood. The leaves on affected canes 

 are dwarfed, the fruit ripens prematurely, is undersized, and 

 often dries up. 



Upon the petioles of the older leaves the disease appears 

 early, spreading thence along the ribs to the leaf. Owing 

 to the one-sided attack upon the veins and petioles, the 

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