6 BULLETIN 4116, U. S. DEPARTMENT OF AGRICULTURE. 
Alternaria producing the seedling leaf-spot and seed injury in 
Louisiana. 
Rice infected with the various forms of fungi which produce fleck- 
ing and decay germinates very poorly as compared with uninfected 
seed. The germ often is killed by the invading parasite (Pls. IT and 
III, A). Wet soils, which tend to check the normal germination and 
development of seedlings, seem to favor the growth of the fungus, 
and the seed may be destroyed and a poor stand result. Seed treat- 
ment before sowing would not eliminate injury done by these fungi 
previously, but might prevent further injury and prevent the spread 
of these organisms. Seed of Honduras rice obtained from California, 
where seed-infesting fungi are rare, and sown in Louisiana germinated 
better than seed of the same variety grown in Louisiana (Tables 2 
and 4). The difference in the percentages of germination is an 
indication, perhaps, of the extent of damage commonly caused to 
seed rice in Louisiana. Of course, if the number of these fungi 
which may be carried in the soil was considered, the damage might be 
ereater. Treated seed from the same lot germinated almost 2 per 
cent better than untreated seed. The soil where this seed was 
sown was in very good condition. The seed was sown late and had 
almost ideal conditions for germination. This gave the untreated 
seed an opportunity to germinate before much injury could be done 
by the fungi carried internally. 
SEED TREATMENT. 
Upon undertaking a seed treatment it was soon found that sur- 
face sterilization was of no value. Seeds were dehulled and treated 
for 3 minutes in 50 to 70 per cent alcohol and then soaked for 10 
minutes in bichlorid of mercury solution (1 to 1,000) with no effect 
(Pls. IV, A; V; and VI, A). Godfrey® treated dehulled seed by the 
Jensen modified hot-water method and found that the sclerotial form 
was killed. Dehulling the seed, of course, would not be at all prac- 
ticable, so an attempt was made to find out to what extent, if at all, 
hot water could be used for treating rice in the hull. It was found 
that practically all the fungi in .the seed could be killed without 
injury to the seed germ if care was exercised in carrying out the 
treatment. 
Rice, which has close-fitting, tough glumes, requires a much longer 
presoaking in tepid water and a more extended soaking in hot water 
than the other small grains. The best method found was to pre- 
soak the seed overnight in water which was somewhat warm to 
begin with, and hence more effective than cold water, and then, 
subsequently, to treat the seed with hot water. Before beginning 

5 Godfrey, G.H. Op.cit. 1920. 


, ow 
