910 
Journal of Agricultural Research 
Vol. XXVIII, No. 9 
STUDIES ON CONIDIA 
In the present investigations Fusarium moniliforme has been found very com¬ 
monly associated with corn. Extensive isolations have been made from various 
parts of plants taken from cooperative experimental plots of the United States 
Department of Agriculture at Bloomington, Ill., and Madison, Wis., at three 
different times since the fall of 1919, by Helen Johann and the writer. In all, 
about 350 plants have been studied, and F. moniliforme has appeared very 
frequently. 
Some of the cultures of Fusarium moniliforme obtained in this way have been 
kept in the laboratory for observation. The total number isolated was so large 
as to make it impracticable 
to keep all of them. Cul¬ 
tures received from other 
States, namely, Indiana, 
Delaware, Maryland, North 
Carolina, California, Iowa, 
and Kentucky, have been 
added to the number. At 
present the stock includes 
about twenty-five strains. 
It was noticed from time 
to time that these cultures 
differed from each other 
somewhat, and that some of 
them departed from Shel¬ 
don’s description along cer¬ 
tain lines. The production 
of sporodochia was one of 
the most noticeable of these 
points of difference. Some 
cultures developed them 
abundantly, in contrast with 
others where they were pro¬ 
duced rarely or not at all, 
and in the true sporodochia 
a large number of 5-septate 
conidia was found with a 
corresponding maximum 
length greater than that 
given by Sheldon. All of 
them, however, had the ca- 
tenulate microconidia of Fusarium moniliforme (fig. 1) and were confined to the 
same color range. They showed an early vacuolization and degeneration of 
macroconidia and mycelium, suggestive of the Section Roseum. 
A detailed description of two of these cultures or strains, Y 15 and Y 29, will 
serve to illustrate some of the variations. Moreover, these two strains are of 
basic importance in the present discussion. 
Descriptions are based on cultures grown at room temperature and on oat 
agar made according to the formula of Sherbakoff (#4, p- 105) unless there is 
some statement to the contrary. Use of oat agar, potato-dextrose agar, potato- 
dextrose agar acidified, rye agar, bean agar, steamed rice, potato tuber plugs, 
Melilotus stems, sterilized wheat heads, sterilized corn stalks, and corn agar for 
these Fusaria has indicated that there is little to be gained from the variety, 
and that, in general, the oat agar is most satisfactory. 
Fig. 1.—Microconidia of Fusarium moniliforme Sheldon. Typical 
of all strains observed. X 1733 
