FIG 139 



Canker. This disease is due to the fungus Libertella 

 ulcerata, Massee, but is not severe except where figs 

 are grown under glass. The disease causes the forma- 

 tion of small radiating cracks which eventually form 

 large cankers, de- 

 stroying both bark 

 and cambium. If 

 the canker com- 

 pletely girdles the 

 tree or branch, all 

 that part beyond 

 the canker dies and 

 is soon covered with 

 the fruit of the 

 fungus, which oozes 

 out as numerous 

 hair-like processes. 

 These processes 

 consist of spores, 

 held together by a 

 gelatinous sub- 

 stance which dries 

 and becomes hard, 

 but softens in w r ater 

 and is readily scat- 

 tered. 



Another canker 

 has recently been 

 reported from 

 Louisiana, U.S.A., 



and described by FIG. 58. Twigs of fig affected with Tubercular ia fid. 

 -17 n /TV rr>\ (Photo by C. W. Edgerton.) 



Edgerton (Fig. 58) 



as due to Tuber cularia fid. Mr. Edgerton describes it 



as follows : 



The disease is characterised by the shrinking and drying 

 out of the tissue surrounding a fruit scar, accompanied by an 

 increased growth of the healthy surrounding tissue, and followed 

 later by a dropping out of the dead part, leaving an open 

 wound in the branch. The cankers are perfectly characterised 



