CHERRY DISEASES 



189 



killing, of the affected parts (Fig. 51). Infected branches be- 

 come more numerous and are more or less elongated (Fig. 51). 

 Authorities disagree on the matter of whether affected twigs 

 are thickened. In some cases the twigs become so numerous 

 that they are not able to bear their own weight, and as a result 

 the abnormal portion of the 

 tree droops. In such cases 

 the tips of the branches usu- 

 ally turn upward (Fig. 51). 

 The over-production of 

 branches at a local region 

 results in a broom-like 

 growth. Some of the brooms 

 are large enough and so con- 

 spicuous that they are very 

 noticeable from a distance. 

 This is especially true when 

 the tree is bare of leaves. 

 These broom-like growths are 

 also conspicuous at blossom- 

 ing-time ; for they bear few 

 or no flowers, hence the af- 

 fected portion stands out 

 in bold contrast to the 

 remaining blossoming- 

 branches. Leaves also come 

 out on brooms before they 

 do on healthy branches. 



Affected leaves take on a crinkled shape and a reddish dis- 

 coloration. The disease on leaves is usually referred to as leaf- 

 curl, and the abnormalities exhibited are very much like those 

 of the peach leaf-curl (see page 277). Affected leaves fall 

 prematurely and later new foliage appears. On their lower 

 surfaces a whitish coat may be found prior to defoliation. 



FIG. 51. Witches'-broom on cherry. 



