XIII, A, 5 Reinking: Philippine Economic-Plant Diseases 



251 



and during damp weather. Dis- 

 eased ears may be entirely 

 covered with the fungus growth 

 or only partially covered in 

 blotches. Infected kernels do 

 not mature, and the starch is 

 partially consumed and becomes 

 powdery. 



Causal organism. — No spores 

 are developed. A sterile mass 

 of mycelium covers the grain. 

 The fungus grows readily in 

 pure culture, producing a thick 

 woolly mass. 



Control. — The disease is only 

 severe during damp, hot weather. 

 Corn should not be planted too 

 closely, so as to allow for plenty 

 of aeration. 



H elininthoHporium inconspicuuin 

 C. et. E. a, group of conidio- 

 phores (X 320) ; b, conidium 

 from tassel of com (X 320) ; e, 

 conidia from leaf of corn ( X 

 320). 



LEAF SPOT: HELMINTHOSPORIUM INCONSPICUUM COOKE ET ELLIS 



Symptoms. — This is a common disease in the Philippines, 

 which at times may be extremely destructive. At the College 



of Agriculture entire plots of 

 field and sweet corn have been 

 destroyed. The disease is es- 

 pecially severe on newly intro- 

 duced corn that is not accli- 

 mated and is in a weakened 

 condition. It is present on the 

 native corn, but generally does 

 little damage. Leaves and tas- 

 sels are attacked. On the leaves 

 are produced at first minute, 

 roundish brown spots, which 

 gradually increase in size, be- 

 coming somewhat oval, the long 

 axis of the spot being parallel 

 with the veins (Plate XX, fig. 

 1 ) . Spots may increase in size, 

 elongating into stripes, or may 

 Heiminthosporium inconspicuum Yxxxi together, coverlng large 



C. et E. a. germinating coni- sUrfaCeS of the leaf. Old SpotS 

 diophores (X 320) ; 6, germi- i , . , i- i 3 , 



nating conidia (X 320). aud stnpes have a lighter yel- 



