xiii, A, 5 Reinking: Philippine Economic-Plant Diseases 227 



GLUME spot: phyllosticta glumarum saccardo 



Symptoms. — Dead and weakened plants are subject to the 

 attacks of numerous fungi. Minute black specks on the glumes 

 are the pycnidia of this fungus. The fungus apparently attacks 

 the plant as a saprophyte and causes little damage. 



Other fungi found on dead glumes are Leptosphaeria {Leptos- 

 phaerella) oryzina Sacc, Calonectria perpusilla Sacc, Haplogra- 

 phium, chlorocephalwm (Fres.) Grove, Clasterosporium puncti- 

 form^e Sacc, Myrothecium. oryzae Sacc, Helminthosporium, and 

 Septoria miyakei Sacc. What relation, if any, these fungi have 

 to disease production has not been determined. 



leaf spot: cercospora 



SyTTiptoTTis. — Elongated brownish spots are frequently pro- 

 duced on the leaves (Plate VIII, fig. 5). These spots, when 

 older, have ashen-gray centers and yield Cercospora spores. 

 Little injury is caused. 



leap spot: phyllosticta miurai miyake 



Symptoms. — Dead and weakened leaves are frequently spotted 

 with the minute black pycnidia of this fungus. The fungus 

 appears to be saprophytic and consequently does little damage. 

 stem rot: rhizoctonia 



Symptoms. — The common soil Rhizoctonia may attack the base 

 and outer older leaf sheaths of upland rice plants. Under cer- 

 tain conditions, such as in thickly planted fields during damp hot 

 weather, severe injury may be produced. Severely attacked 

 plants may have the entire outer group of leaves killed. The 

 fungus mycelium can be seen on the dead leaves, which are 

 frequently cemeted together by the mycelial strands. Plants 

 attacked in this manner are stunted and bunchy due to the 

 abnormal production of stools. Heads produced by such plants 

 are frequently sterile. In less severe attacks spots are produced 

 on the outer older leaf sheaths. These spots are from 1 to 2 

 centimeters long by 1 centimeter wide. Often they run together 

 producing large blotches. Spots have straw-colored centers 

 with wide borders of dark brown. 



Catis'al organism,. — The organism producing this disease is 

 similar to that described under blight of soy beans and that 

 causing stem rots and damping off. No spores have been ob- 

 served. The mycelium spreads over and through the leaves and 

 in advanced stages produces brown sclerotial bodies on diseased 

 parts. 



