90 



DISEASES OF ECONOMIC PLANTS 



Fig. 35. — Hypochnose, showing aclerotia 

 on twig at left and rhizomorphic strands 

 pn twig at right. Original. 



gether with the sclerotia 

 •and extending along the 

 twig longitudinally are 

 also found silvery, glis- 

 tening, thread-like, fun- 

 gous growths. 



This fungus hibernates 

 in the sclerotia on or near 

 the terminal bud and 

 thence invades the new 

 twigs as they develop, 

 reaching out upon each 

 leaf, spreading over its 

 under surface in almost 

 invisible thinness, and 

 causing it to droop, die, 

 and eventually to fall 

 away. Thus in early au- 

 tumn such trees are nearly 

 or quite defoliated. The 

 fruit may be also invaded 

 by the fungus. This an- 

 nual premature loss of leaf 

 is a serious injury to the 

 tree, hindering its proper 

 growth and preventing 

 proper fruitage. 



Hypochnose, first de- 

 scribed from Brazil, is 

 known from Maine to 

 Florida in the United 



