TOXICITY OF VARIOUS NITRATES TO MONILIA SITOPHILA 629 
When sodium nitrate at a concentration of 0.533 molar was 
combined with the starch medium no germination occurred. 
When the concentration was 0.400 molar a small amount of 
growth was obtained. In still lower concentrations enough 
mycelium was produced to be easily visible to the naked eye. It 
was found that growth was much retarded in media containing 
the higher concentrations of sodium nitrate. This shows that 
near the limit concentration the rate of growth of Monilia, de- 
creases as the amount of sodium nitrate is increased. 
Barium nitrate in the starch medium at a concentration of 
0.187 molar inhibits the germination of the spores. At a con- 
centration between 0.156 molar and 0.094 molar, the spores 
germinate but produce such a small amount of mycelium that it 
is not visible except under the microscope. At a concentration 
of 0.062 molar or less, good growth was obtained. 
When the concentration of urea nitrate in the starch medium 
Was 0.125 molar, the spores were unable to germinate. When the 
concentration was reduced to 0.063 molar, the spores germinated 
but produced such a small amount of mycelium that it was not 
visible to the naked eye. Good growth was obtained when the 
concentration of urea nitrate was 0.05 molar or less. 
In starch media containing ammonium nitrate at a concen- 
tration of 0.05 molar none of the spores germinated, but when the 
concentration was 0.038 molar, they germinated and produced 
microscopic growth. When the concentration was reduced to 
0.025 molar or less, abundant growth occurred. 
Aluminum nitrate in starch media at a concentration of 0.0025 
molar inhibits the germination of the spores. At a concentration 
of 0.0013 molar the spores germinate and produce microscopic 
mycelia, while at concentrations of 0.0006 molar or less, good 
growth is obtained. 
Ferric nitrate in starch media is quite toxic to the spores of 
Monilia. In concentrations of 0.00027 molar or less, good gr owth 
was obtained, but in more concentrated media little or no growth 
occurred. 
Silver nitrate is even more toxic than ferric nitrate; when its 
concentration was 0.00027 molar, the spores germinated, but 
Produced only microscopic mycelia. In more concentrated media 
no germination took place. 
