XIII, A, 4 Reinking: Philippine Economic-Plant Diseases 173 



fungus has not been prevalent enough to cause any serious 

 damage (Plate XIV, fig. 1). It has not been identified. 



Steirochaete ananassae Sacc. and Diplodia ananassae Sacc. 

 are found on dead leaves. 



ANDROPOGON SORGHUM LINN. (SORGHUM VULGARE PERS.) . 

 SORGHUMS, KAFFIRS, MILOS 



GRAIN mold: helminthosporium caryopsidum saccardo 



Symptoms. — Grains are frequently covered with a dense black 



or sometimes dark greeijish mold. Generally little damage is 



done, but in severe cases of infection seeds may be destroyed. 

 Catisal organism. — The mold is made up of mycelium, coni- 



diophores, and the many-celled, curved brownish conidia. 



Control. — The seeds should be carefully dried and stored in 



a well-ventilated dry place. 



KERNEL smut: USTILAGO SORGHI (LK.) PASSAEINI 



Symptoms. — This disease though not serious is, however, 

 occasionally present. Individual grains of the panicle are 

 affected. Diseased heads appear normal except for the infected 

 grains. Smutted grains are much enlarged and have a black 

 smutty mass of spores protruding between the glumes (Plate I, 

 fig. 3). 



Caitsal organism. — The smutty mass is composed of round, 

 smooth, brownish smut spores. These spores germinate by the 

 production of a promycelium, from which are produced hyaline 

 sporidia. 



Control. — Only seeds free from smut should be planted. All 

 diseased heads should be collected and burned. Crop rotation 

 will check the disease. 



LEAF spot: PHYLLACHORA sorghi v. hohnel 



Sym/ptom^. — Leaves are badly attacked by this fungus, which 

 produces thickly scattered black spots over the surface. Spots 

 are small, 1 to 4 millimeters in diameter, roundish, sometimes 

 elongated, raised, extending through the leaf on both surfaces, 

 and are made up of hard stromatic masses of the fungus (Plate 

 I, fig. 1). These black stromatic masses may be surrounded 

 by a dark reddish or yellowish ring, produced by the discolora- 

 tion of leaf tissue. The reddish spots frequently run together, 

 producing a much-reddened leaf. The disease is often serious 

 enough to destroy leaves for use as fodder, as well as to lower the 

 \dtality of plants. 



Causal organism. — Within the stromata are produced usually 

 one or two perithecia, which contain numerous asci, ascospores, 



