8 
Colorado Agricultural College 
Panicum Millets (Panicum niiliaceum) 
The smut in Panicum millets, such as Proso or Red Hog varie¬ 
ties, is especially characteristic in appearance. Here the heads are 
always empty and fully destroyed. They are noticeably shorter than 
normal ones, frequently exposed but very little beyond the leaf sheath. 
The smutted ovaries of the grain are massed together, enclosed by a 
whiteish membrane, the whole resembling a thickened or an elongated 
boil. Smutted heads (panicles) appear in much contrast to the nor 
mal spreading ones and are therefore readily recognized, even at a 
distance. Usually the smut masses are ruptured or broken before 
liarvest time and the black, powdery mass is scattered by wind and 
insects to the healthy grain of other plants. Certain insects feed upon 
millet smut, more or less, and break open the enveloping glumes, ex¬ 
posing the dark spore masses and thereby rendering the affected heads 
more conspicious and easily recognizable. (Figs. 9 and 10.) 
DESCRIPTION OF CASUAL ORGANISMS OF SMUT 
It should be generally recognized that all the smut diseases, as 
well as fungus diseases in general, are caused by minute and parasitic 
forms of plant life, so small in fact that the individuals cannot be seen 
with the naked eye. Such disease-causing organisms are collectively 
referred to the group known as “fungi”, while an individual of the 
group is called a “fungus”. 
Obviously, the fungi are very simple plants, the plant body itself 
consisting of miuute threads (mycelium) which penetrate and destroy 
living plants and thereby give rise to some form of disease. In the 
case of the smut diseases, the fungus becomes evident in the grain 
generally, and is represented by the masses of black, powdery spores 
which constitute the reproductive bodies of the fungus. From the 
standpoint of their role in perpetuating the disease, the spores may be 
likened to the kernels of corn in which lies the power of producing 
new corn plants. Similarly, the smut spores are the bodies which 
carry the disease to new plants, resulting in the continued increase of 
smut, year after year. 
The spores of the millet smut fungi are rounded and very small, 
the individual spores being visible only under high-power magnifi¬ 
cation. If placed side by side, it would require 20 spores to measure 
the width of one human hair. (Fig. ii.) Owing to the small size 
and light weight of spores, they are readily disseminated by air cur¬ 
rents, rain, and insects, and upon coming in contact with healthy 
grains, readily find lodgment under the scales or any protective parts 
of the grain. 
