CEREAL INVESTIGATIONS 
Oct. 15,1925 Leaf spot of Maize Caused by Ophiobolus heterostrophus 709 
In the foregoing, attention has been confined to leafspot and leaf 
blight of maize, and the congeneric causal organisms responsible 
for them, without reference to the occurrence of Helminthosporium 
infection of the male inflorescence of maize, mentioned in several 
publications based on studies in the Tropics. Reinking in his 
discussion of H. inconspicuum {10), states that: “A black mold is 
produced on the tassel * * *. Helminthosporium curvulum Sacc. 
has been reported from the tassels of corn.” In another paper {11) 
the same matter is restated as follows: “A black mold is also pro¬ 
duced on the tassel. Saccardo has determined this fungus as Hel¬ 
minthosporium curvulum Sacc.; however, it produces a disease identi¬ 
cal with the earlier described disease caused by Helminthosporium 
inconspicuum .” In a host index of Philippine economic fungi, 
H . curvulum is enumerated among the fungi on corn as u tassel 
mold.” 
Mitra, in his description of maize blight, states that— 
In the male inflorescence the disease assumes a blackish mold-like appear¬ 
ance on the surface of the glumes of male spikelets. The attack is not extensive 
and scattered spikelets here and there are infected. The mycelium ramifies 
within the tissues of the paleae and the stamens. 
* * * Conidia of the fungus from the glumes of male spikelets are a little 
longer and more curved than those of the leaf fungus and has been named 
H. curvulum Sacc. In the Philippines it is described by this name but here in 
cultures it resembles the strain from the leaf and, when inoculated on the leaves, 
produces the same kind of spots as the leaf strain. 
To these references may be added a passage from the writer’s ac¬ 
count {2, p. 716) of Helminthosporium turcicum , regarding the conidia 
obtained from affected maize tassels collected in the Philippines by 
W. H. Weston, jr.: 
Preparations made from the fructifications on the tassel, however, showed 
conidia which, while of the same color and approximate maximum length, were 
perceptibly inferior in diameter, measuring approximately 11 to 14 y. in this 
dimension; more abundantly septate, 12 transverse walls being not uncommon; 
usually quite distinctly curved; and evidently similar to those figured by Rein¬ 
king (10, pi. 20, B, C). * * * If the forms on the leaves and on the tassels 
should indeed prove to be identical, the morphology of Helminthosporium turcicum 
as generally understood would stand in considerable need of revision. 
Subsequent to the discovery of the leaf-spot disease, the writer took 
occasion to examine two packets of affected maize tassels deposited 
in the herbarium of the Office of Pathological Collections by C. F. 
Baker under the label: 
“ Fungi malayana No. 239 Helminthosporium curvulum Sacc. n. sp. on Zea 
mays. Mount Maquiling, near Los Banos, Province Laguna, Philippines. Det. 
by Saccardo. Date Aug., 1914.” 
In general appearance the specimens closely resembled those collected 
by Weston, tne fructifications where best developed being crowded 
on the scales as a velvety layer (fig. 3, F) very similar to the growth 
of Helminthosporium oryzae B. de H. on the inflorescence of rice. 
Microscopic examination revealed two species of Helminthosporium, 
one with relatively small sporophores (4 to 6 by 100 to 225 p) and 
small 3-to-4 septate, curved conidia, measuring 9 to 14 p in diameter 
by 20 to 30 p in length, the middle cell of which was considerably 
smaller and darker than the other segments (fig. 3 Ba to Bf, Ca to Cm). 
The other fungus was apparently identical with the one found on 
Weston’s material, the conidiophores measuring usually from 4.5 
73704—261-2 
