408 



MANUAL OF FRUIT DISEASES 



if formed at all, never reaches full maturity, but ripens pre- 

 maturely or dries up. 



The petioles of the oldest leaves are attacked soon after the 

 canes are affected. Purplish spots as described for the canes 



above are developed. The 

 affected tissue enlarges 

 along the petiole, finally 

 reaching the leaf proper. 

 On the leaf whitish, blister- 

 like lesions appear. The 

 leaves then become dis- 

 torted, their edges rolling 

 in toward the midrib. 

 Spots on the leaf-blade 

 are similar to those on 

 the canes, although smaller ; 

 they are one-twenty-fifth 

 of an inch or less in diam- 

 eter. They are closely dis- 

 tributed, but rarely coa- 

 lesce. Frequently the 

 diseased area, in which 

 most of the tissue is dead, 

 becomes separated from 

 the surrounding healthy 

 tissue and the leaf shows 

 a shot-hole effect. Leaves 

 on the laterals of new canes 

 do not ordinarily become 

 diseased. 



Anthracnose shows on 

 the fruit. The upper drupels are more commonly attacked. 

 Many fruits are affected while still green in color and 

 sometimes before they are larger than a pea. A small brown 



FIG. 119. Anthracnose on canes of 

 black raspberry. 



