190 



DISEASES OF ECONOMIC PLANTS 



Foot rot, mal-di-gomma (Fusarium Limonis Briosi). — 

 The first symptoms of the disease are abundant exuda- 

 tions of gum upon the trunk of the tree ; at the same time 

 the bark becomes brownish in patches, which are thrown 

 off and other patches come. The tree appears as though it 

 does not secure sufficient nourishment, the leaves becoming 

 yellow, scanty, and smaller than usual. 



Though the trees bear considerable fruit, the amount 

 of damage in Florida is estimated at $100,000 annually. 

 No treatment has proved satisfactory. 



FIG 



Fruit rot {C olletotrichum Carica S. & H.). — This disease 



was first described in 1909 by the authors. A rot due 

 to an undescribed species of 

 Collectotrichum, and possibly 

 identical with this, was re- 

 ported from Louisiana in 

 1907. 



Fruit rot is easily recog- 

 nized by the sunken, rotten, 

 more or less circular fruit 

 spots, nearly always covered 

 with a white mass of fungous 

 mycelium. As they grow 

 older they produce numerous 



pustules of the salmon-pink color characteristic of the 



spores. 



The amount of damage caused is very great by reason 



of premature falling of the fruit, at times destroying the 



whole of the crop. 



Fig. 83. — Fig in well-advanced stage 

 of fruit rot. Original. 



