Sept. 15, 1925 
Oladosporium Leaf Mold of Tomato 
537 
drying, these fragments were not easily dislodged. Likewise, 
Oladosporium spores from infected sepals might lodge on the surface 
of the seed. The likelihood of seedling infection from the seed-borne 
fungus depends upon a number of factors, some of which have been 
studied. 
The viability of the fungus in and on the seeds has been proved 
and its behavior determined by incubating the seeds on moist filter 
paper in damp chambers. Sporulation occurred on both the actually 
infected and the contaminated seeds. In some cases spores formed 
in abundance after four days at room temperature. Eleven seeds 
with infected hila were incubated at 27° C., and sporulation occurred 
on 6 at the end of 13 days. Thirty seeds bearing blackened tissue 
fragments were similarly incubated, and sporulation occurred on the 
blackened fragments of 3 of them after 13 days. Many of the spores 
germinated in the saturated atmosphere of the damp chamber. 
With regard to the longevity of the fungus in and on the seeds, it 
should be noted that the seeds in the two tests just mentioned had 
been dried only 10 days, while later tests proved the fungus alive 
after one montn. It would seem that the dense mycelial aggregates 
within and upon the seed coat were excellent adaptations for the sur¬ 
vival of long periods of desiccation. Savelli (IS) and later Makemson 
(8, p. 335) found that the spores endured desiccation for six months 
and the latter found that some spores a year old were viable. 
It is important to note that the moisture and temperature con¬ 
ditions conducive to germination of the seed are likewise conducive 
to sporulation as well as to spore germination, particularly if the seed 
lies upon the surface of the soil or if the seed coat is carried up by the 
cotyledons, a very common occurrence among tomato seedlings. It 
is to the advantage of the parasite that the infected or contaminated 
seed should germinate and carry the seed coat up above ground. 
The germinability of the seeds bearing tissue fragments obviously 
will be unharmed. Of the 30 seeds of this type tested on moist filter 
papers as already mentioned, 27 germinated and 14 carried the testa 
up an the cotyledons. In. one of these latter cases the fungus was 
sporulating on the tissue fragment. Of the seedlings grown in sand 
or greenhouse soil, however, a lower percentage carry up the seed 
coat. Of the 11 seeds with infected hila which were similarly tested, 
8 germinated and one carried up its seed coat (pi. 5, C), in which 
case the the fungus was found sporulating on the infected tissue of 
the hilum. In another test, 9 out of 10 infected seeds germinated. 
Thus, apparently, the invasion of the seeds by Oladosporium fulvum 
does not materially reduce their germinability, and such seeds, as 
well as those bearing infected tissue fragments, will germinate and in 
certain cases carry the seed coat up into the air. 
The tests just noted show that, by means of infected or contamin¬ 
ated seeds, the parasite might be introduced into the seed bed and 
be carried above ground in a sporulating condition and that spore 
infection of near-by seedlings might very easily occur, whether the 
offending seedlings were themselves infected or not. 
However, in the case of hilum infection, there is ample oppor¬ 
tunity for the seedling itself to become infected, because both radicle 
and cotyledons emerge from the seed coat directly through the 
infected region (pi. 5, C). Observation of a specific instance where 
a radicle, in contact with an abundance of the spores and mycelium 
