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smut, including that of wheat. It was Kiihn* again who, sixteen 
_ years after his first results were published, finally discovered the 
_ penetration of the mycelium of Corn smut into its host. He found 
~~ that mycelium from the germinating spores entered at the root node 
and the lowest joint of the stem, 2. e., at the most tender part, and © 
~ only when the corn was young; when it is old the smut apparently 
cannot getin. This may be turned to practical account in preventive 
~ - measures as described under remedies. 
(f) DISTRIBUTION AND SEVERITY, 
Prof. William Trelease has recently found Corn Smut growing upon 
Euchlena luzurians. With this exception it is confined to corn, so 
far as known, differing in this respect from Ustilago segetum, which 
grows on wheat, oats, barley, and various grasses. 
~ It is distributed throughout Europe and America. In the cooler 
~ . regions, what corn is cultivated is comparatively free from smut, but 
_ ‘in regions well adapted to the culture of corn, it is often very de- 
structive. In the valleys of the Rhine and Rhone it sometimes 
_ destroys nearly the whole crop. In the Rhine valley in 1880, the 
crop harvested scarcely replaced the corn used for seed. In the 
United States the extent of the injury is very variable. Mr. C. 
-. H. Peck records a case which occurred in 1868. He noticed a field 
of corn near Albany, N. Y., which just before flowering appeared 
as thrifty and promising as any in that county, but later almost 
. every hill was attacked by smut, and at least one out of every four ears. 
It was especially injurious to sweet corn about Washington, D. C., 
~ in'1886. 
Re Prot. B. D. Halsted + states that at Ames, Iowa, in 1886, the col- 
lege corn-field had sixty-two hundredths of 1 per cent. of the ears 
‘smutted. Prof. C. H. Bessey states that a destruction of 15 per cent. 
frequently occurs, and in one field he observed 66 per cent. of the corn 
smutty. : 
It is generally believed that wet weather is favorable to smut, and 
that corn is likely to be, and is, badly, damaged in a wet season. 
A correspondent of the Country Gentleman, in September, 1878, writes 
that a wet season has been accompanied by much smut. Tulasne 
states that in 1846, a dry season, the corn crop in the valley of the 
Rhone was partly destroyed, and says the smut may be very injuri- 
,. ous in very dry years. Prof. W. H. Henry states that the smut was 
very destructive about Madison, Wis., in 1881, causing a loss of 5 
to 25 per cent. of the whole crop, while in 1882 there was very little 
smut. The writer observed that corn was badly smutted in north- 
ern Illinois in the summer of 1881, which was very dry. 
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(g) NATURE OF INJURY CAUSED BY CORN SMUT. 
During nearly the whole growth of the corn the fungus is growing 
withinit. It produces little apparent effect until the time of fruiting, 
*Bot. Zeit., Vol. XXXII, p. 122. 
+ Bull. Iowa Agr. Col., Nov., 1886. Professor Halsted writes me, the summer 
of 1887, like that of 1886, was a very dry one at Ames, and that in 1887 the smut 
was very abundant. 
{In many corn-fields in Texas, as far west as El Paso, I observed more or less Corn 
Smut the past summer. The season was very dry.—F. L. 8. 
, AG 87 25 
