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The Philippine Journal of Science 



to the portion between the larger veins. These spots enlarge 

 lengthwise and may advance over the larger veins producing 

 more or less of a blotch. Older diseased portions may be 4 milli- 

 meters wide and from 2 to 20 centimeters long. These stripes 

 still have a watery appearance, but change to a light brown. 

 Amber-colored droplets of bacteria ooze from these diseased 

 portions. As the leaf dries out these droplets of bacteria harden 

 producing small roundish amber-colored beads. The disease 

 appears to be most prevalent on succulent plants. 



Causal organism. — Microscopic examination and cultures in- 

 dicate that the disease is due to bacteria. Under the micro- 

 scope, bacteria can be observed to stream from the vascular 

 bundles. A detailed study is now in progress. 



Control. — No control can be given until the disease has been 

 carefully studied. 



FALSE SMUT OR LUMP SMUT: USTILAGINOIDEA VIRENS (CKE.) TAKAHASHI 



Symptoms. — This conspicuous disease is found in practically 

 all rice-growing sections. Only a few grains in each panicle 

 are attacked. Diseased grains are characterized by the pro- 

 duction of large masses of sclerotia. Infected grains are en- 

 larged, oval to spherical, from 2 to 6 millimeters in shortest 

 diameter. The enlargement is due to the production of a sclero- 

 tial mass, which in its early stages has a bright yellow covering, 

 but later is coated with a dark green powder (Plate VIII, fig. 2) . 



During damp weather the dis- 

 ease may be severe and seems to 

 be more prevalent on certain 

 varieties of rice. 



Causal organism. — This dark 

 green powder is composed of 

 spores. No perithecia or asco- 

 spores have been observed in the 

 sclerotial mass. The spores are 

 small and brown and covered 

 with short stout spines or echinu- 

 lations. Germination takes 

 place by the production of a 

 germ tube with an enlarged 

 knoblike end (fig. 25). 

 Control. — The disease may become epidemic, due to the ac- 

 cumulation of sclerotial bodies that are allowed to fall upon 

 the ground. All diseased heads should be collected and burned. 

 Crop rotation should be practiced. 



Vstilaginoidea virens (Cke. ) Tak. 

 a, spores (X 1,800) ; 6, ger- 

 minating spores (X 1,800). 



