100 DISEASES OF TROPICAL PLANTS 



CH. 



disease of the joints of the stalk. Beginning as a very 

 small spot on the sheath-node (the thickened turgid 

 bright green ring at the base of every leaf-sheath, just 



FIG. 46. Rice affected with the blast disease. 



1, Diseased leaf; 2. diseased ear; 3, conidiophores and spores ; 4, germinating spores in water ; 

 5, formation of chlamidiospores. 



above the true joint of the stem), the tissue gradually 

 dies until the stalk at this point is partially 'or com- 

 pletely killed. A brownish coloration spreads up the 



